Ofloxacin

Drug overview for OFLOXACIN (ofloxacin):

Generic name: OFLOXACIN (oh-FLOX-uh-sin)
Drug class: Quinolones
Therapeutic class: Anti-Infective Agents

Ofloxacin is a synthetic fluoroquinolone anti-infective agent.

No enhanced Uses information available for this drug.

DRUG IMAGES

OFLOXACIN 400 MG TABLET

The following indications for OFLOXACIN (ofloxacin) have been approved by the FDA:

Indications:
Bacterial urinary tract infection
Chlamydia cervicitis
Chlamydia trachomatis pelvic inflammatory disease
Chlamydia trachomatis urethritis
Citrobacter complicated UTI
Citrobacter cystitis
Complicated E. coli UTI
Complicated Proteus UTI
Complicated UTI with Pseudomonas aeruginosa
E. coli cystitis
E. coli prostatitis
Enterobacter cystitis
Gram-negative aerobic bacillary pneumonia
Haemophilus influenzae bronchitis
Haemophilus influenzae pneumonia
Klebsiella complicated UTI
Klebsiella cystitis
Lower respiratory infection
Nongonococcal urethritis
Pneumonia
Proteus cystitis
Pseudomonas aeruginosa cystitis
Skin and skin structure infection
Skin and skin structure Proteus infection
Skin and skin structure Streptococcus pyogenes infection
Staphylococcus aureus skin and skin structure infection
Streptococcal pneumonia
Streptococcus pneumoniae bronchitis

Professional Synonyms:
Bacterial infection of the prostate due to E. coli
Bronchitis due to Diplococcus pneumoniae
Bronchitis due to Fraenkel's Pneumococcus
Bronchitis due to Fraenkel-Weichselbaum Pneumococcus
Bronchitis due to H. flu
Bronchitis due to H. influenzae
Bronchitis due to Haemophilus influenzae
Bronchitis due to Hemophilus influenzae
Bronchitis due to influenzae Bacillus
Bronchitis due to Pfeiffer's Bacillus
Bronchitis due to Pneumococcus
Bronchitis due to Pneumonococcus
Bronchitis due to Streptococcus pneumoniae
Cervicitis due to Chlamydia trachomatis
Complicated Pseudomonas aeruginosa urinary tract infection
Complicated urinary tract infection due to Citrobacter
Complicated urinary tract infection due to Escherichia coli
Complicated urinary tract infection due to Klebsiella
Complicated urinary tract Proteus species infection
Complicated UTI due to Citrobacter species
Complicated UTI due to E. coli
Complicated UTI due to Klebsiella species
Complicated UTI due to Proteus species
Complicated UTI due to Pseudomonas aeruginosa
Cystitis due to Aerobacter species
Cystitis due to Citrobacter species
Cystitis due to E. coli
Cystitis due to Enterobacter species
Cystitis due to Escherichia coli
Cystitis due to Klebsiella species
Cystitis due to Proteus species
Cystitis due to Pseudomonas aeruginosa
H. flu pneumonia
H. influenzae pneumonia
Hemophilus influenzae pneumonia
Infection of skin and/or subcutaneous tissue
Influenza Bacillus pneumonia
Lower respiratory tract infection
NGU due to Chlamydia trachomatis
Nongonococcal urethritis due to Chlamydia trachomatis
Pelvic inflammatory disease due to Chlamydia trachomatis
Pfeiffer's Bacillus pneumonia
PID due to Chlamydia trachomatis
Pneumonia due to gram-negative organism
Pneumonia due to Haemophilus influenzae
Pneumonia due to Streptococcus species
Pneumonia due to Streptococcus spp.
Prostatitis due to E. coli
Prostatitis due to Escherichia coli
Skin & skin soft tissue Streptococcus pyogenes infection
Skin and skin soft tissue Proteus infection
Skin and skin soft tissue Staphylococcus aureus infection
Skin and soft tissue skin infection
Trachelitis due to Chlamydia trachomatis
Urethritis due to Chlamydia trachomatis
Urinary cystitis due to Citrobacter species
Urinary cystitis due to Enterobacter species
Urinary cystitis due to Escherichia coli
Urinary cystitis due to Klebsiella species
Urinary cystitis due to Proteus species
Urinary cystitis due to Pseudomonas aeruginosa

The following dosing information is available for OFLOXACIN (ofloxacin):

Dosing
Administration
OFLOXACIN
OFLOXACIN

The usual adult oral dosage of ofloxacin is 200-400 mg every 12 hours.

Ofloxacin is administered orally. Although ofloxacin also has been administered IV, a parenteral preparation of the drug is no longer commercially available in the US. While presence of food in the GI tract can decrease the rate and/or extent of absorption of ofloxacin, this is not usually considered clinically important and the manufacturer states that the drug can be given without regard to meals.

Milk and yogurt do not appear to affect GI absorption of ofloxacin. (See Pharmacokinetics: Absorption.) To minimize the possibility of interference with the GI absorption of ofloxacin, patients should be instructed not to ingest antacids containing calcium, magnesium, or aluminum, sucralfate, metal cations such as iron or zinc (including multivitamin preparations containing zinc), or buffered didanosine preparations concomitantly with or within 2 hours of an ofloxacin dose. (See Drug Interactions.) Patients receiving ofloxacin should be well hydrated and should be instructed to drink fluids liberally. (See Cautions: Precautions and Contraindications.)

Dosing information for OFLOXACIN
DRUG LABEL	DOSING TYPE	DOSING INSTRUCTIONS
OFLOXACIN 400 MG TABLET	Maintenance	Adults take 1 tablet (400 mg) by oral route every 12 hours
OFLOXACIN 300 MG TABLET	Maintenance	Adults take 1 tablet (300 mg) by oral route every 12 hours

Generic dosing information for OFLOXACIN
DRUG LABEL	DOSING TYPE	DOSING INSTRUCTIONS
OFLOXACIN 400 MG TABLET	Maintenance	Adults take 1 tablet (400 mg) by oral route every 12 hours
OFLOXACIN 300 MG TABLET	Maintenance	Adults take 1 tablet (300 mg) by oral route every 12 hours

The following drug interaction information is available for OFLOXACIN (ofloxacin):

Contraindicated
Severe
Moderate

There are 1 contraindications. These drug combinations generally should not be dispensed or administered to the same patient. A manufacturer label warning that indicates the contraindication warrants inclusion of a drug combination in this category, regardless of clinical evidence or lack of clinical evidence to support the contraindication.

Drug Interaction	Drug Names
Live Typhoid Vaccine/Antimicrobials SEVERITY LEVEL: 1-Contraindicated Drug Combination: This drug combination is contraindicated and generally should not be dispensed or administered to the same patient. MECHANISM OF ACTION: The antimicrobial may be active against the organism in the live-vaccine. Antimicrobial therapy may prevent the vaccine organism from replicating enough to trigger an immune response.(1) CLINICAL EFFECTS: Vaccination may be ineffective. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Do not give oral typhoid vaccine until 72 hours after the last dose of antimicrobial. If possible, to optimize vaccine effectiveness, do not start antibacterial drugs for 72 hours after the last dose of oral typhoid vaccine. A longer interval should be considered for long-acting antimicrobials, such as azithromycin.(3) DISCUSSION: Because antimicrobial therapy may prevent sufficient vaccine-organism replication to generate an immune response, the manufacturer of live-attenuated typhoid vaccine and the Centers for Disease Control (CDC) state that the vaccine should not be administered to patients receiving antimicrobial therapy.(1-3)	VIVOTIF

Drug Interaction

Drug Names

Live Typhoid Vaccine/Antimicrobials

SEVERITY LEVEL: 1-Contraindicated Drug Combination: This drug combination is contraindicated and generally should not be dispensed or administered to the same patient.

MECHANISM OF ACTION: The antimicrobial may be active against the organism in the live-vaccine. Antimicrobial therapy may prevent the vaccine organism from replicating enough to trigger an immune response.(1)

CLINICAL EFFECTS: Vaccination may be ineffective.

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: Do not give oral typhoid vaccine until 72 hours after the last dose of antimicrobial. If possible, to optimize vaccine effectiveness, do not start antibacterial drugs for 72 hours after the last dose of oral typhoid vaccine. A longer interval should be considered for long-acting antimicrobials, such as azithromycin.(3)

DISCUSSION: Because antimicrobial therapy may prevent sufficient vaccine-organism replication to generate an immune response, the manufacturer of live-attenuated typhoid vaccine and the Centers for Disease Control (CDC) state that the vaccine should not be administered to patients receiving antimicrobial therapy.(1-3)

VIVOTIF

There are 15 severe interactions. These drug interactions can produce serious consequences in most patients. Actions required for severe interactions include, but are not limited to, discontinuing one or both agents, adjusting dosage, altering administration scheduling, and providing additional patient monitoring. Review the full interaction monograph for more information.

Drug Interaction	Drug Names
Selected Anticoagulants (Vit K antagonists)/Quinolones SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: The exact mechanism is unknown. Some quinolones may affect the metabolism of anticoagulants or the infection process may be responsible for the changes seen. CLINICAL EFFECTS: Concurrent use of quinolones may be associated with an increase in hypoprothrombinemic effects of anticoagulants, which may result in an increased risk of bleeding. PREDISPOSING FACTORS: The risk for bleeding episodes may be greater in patients with disease-associated factors (e.g. thrombocytopenia). Drug associated risk factors include concurrent use of multiple drugs which inhibit anticoagulant/antiplatelet metabolism and/or have an inherent risk for bleeding (e.g. NSAIDs). PATIENT MANAGEMENT: If concurrent therapy is warranted, monitor patients receiving concurrent therapy for signs of blood loss, including decreased hemoglobin, hematocrit, fecal occult blood, and/or decreased blood pressure and promptly evaluate patients with any symptoms. A study suggested not preemptively reducing the dose of warfarin upon initiation of levofloxacin, but instead just a short-term INR follow-up appears reasonable.(33) When applicable, perform agent-specific laboratory test (e.g. INR, aPTT) to monitor efficacy and safety of anticoagulation. Discontinue anticoagulation in patients with active pathologic bleeding. Instruct patients to report any signs and symptoms of bleeding, such as unusual bleeding from the gums or nose; unusual bruising; red or black, tarry stools; red, pink or dark brown urine; acute abdominal or joint pain and/or swelling. The time of highest risk for a coumarin-type drug interaction is when the precipitant drug is initiated or discontinued. Contact the prescriber before initiating, altering the dose or discontinuing either drug. DISCUSSION: A large systematic review was performed on 72 warfarin drug-drug interactions studies that reported on bleeding, thromboembolic events, or death. Most studies were retrospective cohorts. A meta-analysis of 11 of those studies found a higher rate of clinically significant bleeding in patients on warfarin and antimicrobials (OR=1.63; 95% CI 1.45-1.83). Increased bleeding risk was also seen in subgroup analyses with fluoroquinolones (OR=1.68; 95% CI 1.34-2.11).(42) In a study in 16 patients stabilized on warfarin therapy, the addition of ciprofloxacin (500 mg twice daily for 10 days) had no significant effects on INR values and no patients experienced a bleeding event.(1) In a study in 36 patients stabilized on warfarin therapy, the addition of ciprofloxacin (750 mg twice daily for 12 days) had no effects on the amount of S-warfarin. Levels of R-warfarin increased 1.15-fold, concentrations of clotting factors decreased, and the mean PT ratio increased slightly. However, no patient required warfarin dosage adjustment and no bleeding episodes were reported.(2) In contrast to these studies, there have been several case reports of bleeding episodes following the addition of ciprofloxacin to warfarin therapy,(3-9) including 66 reports to the FDA from 1987 to 1997.(4) Of these 66 reports, 15 resulted in hospitalization, 25 in bleeding, and 1 in death.(4) As of January 14, 2004, Health Canada had received 10 case reports of interactions between warfarin and ciprofloxacin. Four of these patients died.(10) Another study showed that ciprofloxacin prolonged release (PR) concomitantly administered with warfarin does not alter the pharmacokinetics and pharmacodynamics of warfarin.(31) In a study in 6 healthy males, concurrent enoxacin did not affect the hypothrombinemic effects of warfarin, but did decrease the clearance of R-warfarin.(11) In a case report, enoxacin did interact with warfarin.(12) Gatifloxacin has been reported to interact with warfarin in a case report.(13) As of January 14, 2004, Health Canada had received 13 reports of interactions between warfarin and gatifloxacin. Two of these patients died.(10) In a study in 16 healthy subjects, the addition of grepafloxacin (600 mg daily for 14 days) had no effects on the pharmacodynamics of warfarin or the pharmacokinetics of grepafloxacin.(14) In a study in 6 patients stabilized on warfarin therapy, the addition of levofloxacin had no effect on INR values.(15) In a study in 16 healthy subjects, levofloxacin (500 mg twice daily for 6 days) had no effects on the pharmacokinetics or pharmacodynamics of a single dose of warfarin (30 mg).(16) In contrast, there are several case reports documenting an interaction between levofloxacin and warfarin.(17-19) As of January 14, 2004, Health Canada had received 16 reports of interactions between warfarin and levofloxacin. One of these patients died.(10) In a retrospective study, the addition of levofloxacin to warfarin therapy showed an increase in INR.(35) However, in another retrospective study, the addition of levofloxacin to long-term warfarin therapy showed no interaction.(34) An article on the pharmacokinetics of levofloxacin states that with warfarin there were no pharmacokinetic alterations detected for either the R- or S-enantiomers and there were no significant differences in prothrombin times.(32) There are several reports of an interaction between moxifloxacin and warfarin.(20-21) As of January 14, 2004, Health Canada had received 12 reports of interactions between warfarin and moxifloxacin.(10) According to the Institute of Clinical Pharmacology, moxifloxacin shows no pharmacokinetic interaction with warfarin.(38,39) According to moxifloxacin official package insert, warfarin did not significantly affect the pharmacokinetics of moxifloxacin because the in vitro studies suggest that moxifloxacin is unlikely to significantly alter the metabolic clearance of drugs metabolized by the cytochrome P450 system.(41) One case report, of an elderly female concomitantly administered moxifloxacin and warfarin, observed an INR increase from 2.3 to 5.1 and development of hemoperitoneum and left abdominal wall hematoma.(40) Another case report of an elderly female concomitantly administered warfarin and moxifloxacin observed a prolonged INR level despite withholding warfarin for 6 days; however, the INR did decrease after 2 days upon discontinuing moxifloxacin.(36,37) Two case reports show an interaction between moxifloxacin and warfarin due to evidence of elevated PT and INR following coadministration.(36) There are case reports documenting interactions between nalidixic acid and warfarin(22-24) and nicoumalone.(25) In a study in 10 healthy subjects, norfloxacin (400 mg twice daily for 6 days) had no effects on the pharmacokinetics or pharmacodynamics of a single dose of warfarin (30 mg).(26) In a case report, norfloxacin did interact with warfarin.(27) As of January 14, 2004, Health Canada had received 6 reports of interactions between warfarin and norfloxacin.(10) There are reports of an interaction between ofloxacin and warfarin.(28-29) In a study in 10 healthy subjects, temafloxacin (600 mg twice daily for 4 days) had no effects on prothrombin times.(30)	ANISINDIONE, DICUMAROL, JANTOVEN, WARFARIN SODIUM
Selected Quinolones/Class IA & III Antiarrhythmics SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Unknown. Possibly additive or synergistic effects on the QTc interval. Proposed mechanisms for this interaction may stem from quinolone inhibition of hepatic cytochromes and/or competitive inhibition of renal elimination via active tubular secretion. Ciprofloxacin and norfloxacin are moderate inhibitors of CYP3A4. Quinidine is metabolized by CYP3A4. CLINICAL EFFECTS: Increased QTc intervals which may result in potentially life-threatening arrhythmias such as torsades de pointes. PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(15) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(15) PATIENT MANAGEMENT: The manufacturers of ciprofloxacin,(1) gatifloxacin,(2) gemifloxacin,(3) levofloxacin,(4) lomefloxacin,(5), moxifloxacin,(6) nalidixic acid,(7) norfloxacin(8) and ofloxacin(9) state that these agents should be avoided in patients receiving Class IA and III antiarrhythmic agents. If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Ciprofloxacin,(1) gatifloxacin,(2) gemifloxacin,(3) levofloxacin,(4) lomefloxacin,(5), moxifloxacin,(6) nalidixic acid,(7) norfloxacin(8) and ofloxacin(9) have the potential to prolong the QTc interval. Torsades de pointes has been reported during post-marketing surveillance in patients receiving lomefloxacin.(5) There are reports of prolonged QTc intervals with levofloxacin and amiodarone(9) and ciprofloxacin(11) with amiodarone or sotalol. However, a randomized, crossover study evaluated seven healthy males in which quinidine sulfate (400 mg) were administered alone then crossed over with ciprofloxacin (750 mg b.i.d. for 5 days) pretreatment. No significant significant differences were found in the quinidine clearance, half-life, or or Cmax or in QRS or QTc prolongation.(10) Another randomized, crossover study was conducted to determine pharmacokinetic interactions between levofloxacin plus procainamide and ciprofloxacin with procainamide. Levofloxacin significantly decreased renal clearance and the renal clearance/creatinine clearance ratios of procainamide and N-acetylprocainamide (NAPA), the major metabolite of procainamide; however, ciprofloxacin only changed the renal clearance of procainamide and NAPA.(13) A pharmacokinetic and pharmacodynamic study evaluated the interaction between ofloxacin and procainamide. Nine healthy volunteers randomly received one dose of procainamide 1 G, including or excluding pretreatment with ofloxacin (400 mg b.i.d. for 5 doses). A 12-point EKG monitored for any pharmacodynamic abnormalities and blood urine samples evaluated for pharmacokinetic variations. The AUC and Cmax for procainamide were increased by 27% and 21% with clearance diminished by 22%.(14) One or more of the drug pairs linked to this monograph have been included in a list of interactions that should be considered "high-priority" for inclusion and should not be inactivated in EHR systems. This DDI subset was vetted by an expert panel commissioned by the U.S. Office of the National Coordinator (ONC) for Health Information Technology.	BETAPACE, BETAPACE AF, CORVERT, DOFETILIDE, IBUTILIDE FUMARATE, NUEDEXTA, PROCAINAMIDE HCL, QUINIDINE GLUCONATE, QUINIDINE SULFATE, SOTALOL, SOTALOL AF, SOTALOL HCL, SOTYLIZE, TIKOSYN
Pimozide/Possible QT Prolonging Agents SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Pimozide has shown to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of pimozide with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(3) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(3) PATIENT MANAGEMENT: The manufacturer of pimozide states that the use of pimozide is contraindicated in patients taking other drugs which prolong the QT interval.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Agents that are linked to this monograph may have been associated with torsades de pointes and/or QT prolongation but at this time lack substantial evidence for causing torsades de pointes.(2) One or more of the drug pairs linked to this monograph have been included in a list of interactions that should be considered "high-priority" for inclusion and should not be inactivated in EHR systems. This DDI subset was vetted by an expert panel commissioned by the U.S. Office of the National Coordinator (ONC) for Health Information Technology.	PIMOZIDE
Droperidol/Possible QT Prolonging Agents SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Droperidol has been shown to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of droperidol with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: Congestive heart failure, bradycardia, use of a diuretic, cardiac hypertrophy, hypokalemia, hypomagnesemia, age over 65 years, alcohol abuse, and the use of agents such as benzodiazepines, volatile anesthetics, and intravenous opiates may predispose patients to the development of prolonged QT syndrome.(1) The risk of QT prolongation or torsade de pointes may also be increased in patients with cardiovascular disease (e.g. myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypocalcemia, or female gender.(3) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(3) PATIENT MANAGEMENT: The manufacturer of droperidol states under precautions/drug interactions that drugs known to have the potential to prolong the QT interval should not be used together with droperidol.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Agents that are linked to this monograph may have been associated with torsades de pointes and/or QT prolongation but at this time lack substantial evidence for causing torsades de pointes.(2) One or more of the drug pairs linked to this monograph have been included in a list of interactions that should be considered "high-priority" for inclusion and should not be inactivated in EHR systems. This DDI subset was vetted by an expert panel commissioned by the U.S. Office of the National Coordinator (ONC) for Health Information Technology.	DROPERIDOL
Ziprasidone/Selected QT Prolonging Agents SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Ziprasidone has been shown to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of ziprasidone with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(1,3) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(3) PATIENT MANAGEMENT: The manufacturer of ziprasidone states under contraindications that ziprasidone should not be used with other drugs that prolong the QT interval such as dofetilide, sotalol, quinidine, other Class Ia and III anti-arrhythmics, mesoridazine, thioridazine, chlorpromazine, droperidol, pimozide, sparfloxacin, gatifloxacin, moxifloxacin, halofantrine, mefloquine, pentamidine, arsenic trioxide, levomethadyl acetate, dolasetron mesylate, probucol or tacrolimus.(1) It would be prudent to avoid the use of ziprasidone with medicines suspected of prolonging the QT interval. If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(2)	GEODON, ZIPRASIDONE HCL, ZIPRASIDONE MESYLATE
Live BCG/Selected Antimycobacterials SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Bacillus Calmette-Guerin (BCG) is a live, attenuated strain of Mycobacterium bovis (M.bovis) used to induce a granulomatous response in the treatment of localized bladder cancer and as a vaccine to prevent tuberculosis.(1-2) Co-treatment with antibacterial agents active against M.bovis may lead to an attenuation of the immune response associated with BCG administration.(1-2) CLINICAL EFFECTS: The effectiveness of chemotherapy may be impaired, or the vaccine may be ineffective. Agents linked to this monograph may have activity against M.bovis: amikacin, capreomycin, ciprofloxacin, clofazimine, cycloserine, ethambutol, ethionamide, gatifloxacin, isoniazid, kanamycin, levofloxacin, moxifloxacin, ofloxacin, rifabutin, rifampin, rifapentine, and streptomycin. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Intravesical instillation of BCG should be postponed during treatment with antibacterials which may decrease effectiveness.(2) Administration of BCG vaccine to patients receiving antibiotic therapy should only be done under close medical supervision.(1) If a patient develops a systemic BCG infection due to intravesicular or vaccine administration, treatment with multiple antimycobacterial agents may be required. DISCUSSION: Because antibiotic therapy may prevent sufficient vaccine-organism replication to generate an immune response, the manufacturer of BCG vaccine states that administration of BCG vaccine to patients receiving antibiotic therapy should only be done under close medical supervision.(1) Pyrazinamide is not included in this interaction as BCG is not sensitive to pyrazinamide.(2)	BCG (TICE STRAIN), BCG VACCINE (TICE STRAIN)
Artemether-Lumefantrine/Possible QT Prolonging Agents SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Concurrent use of artemether-lumefantrine and agents known to prolong the QT interval may result in additive or synergistic effects on the QTc interval.(1) CLINICAL EFFECTS: Concurrent administration may result in prolongation of the QTc interval and life-threatening cardiac arrhythmias, including torsades de pointes. PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(4) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, and/or renal/hepatic dysfunction).(4) PATIENT MANAGEMENT: The UK manufacturer of artemether-lumefantrine states that the use of artemether-lumefantrine in patients taking drugs that are known to prolong the QTc interval is contraindicated. These agents include class IA and III antiarrhythmics; neuroleptics; antidepressive agents; some macrolides, fluoroquinolones, imidazole and triazole antifungals; terfenadine; astemizole; and cisapride.(1) The US manufacturer of artemether-lumefantrine states that the use of artemether-lumefantrine should be avoided in patients taking drugs that are known to prolong the QTc interval. These agents include class IA and III antiarrhythmics; neuroleptics; antidepressive agents; some macrolides, fluoroquinolones, imidazole and triazole antifungals; terfenadine; astemizole; and cisapride.(2) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(3)	COARTEM
Anagrelide/Possible QT Prolonging Agents SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Concurrent use of anagrelide with agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of anagrelide with agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: The US manufacturer of anagrelide states that anagrelide should not be used in patients taking medications known to prolong the QT interval.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: In a thorough QT study, dose-related QT changes were observed with anagrelide. The maximum mean change in QTcI (95% CI) in comparison to placebo was 7.0 (9.8) ms and 13.0 (15.7) msec following doses of 0.5 mg and 2.5mg, respectively.(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(3) One or more of the drug pairs linked to this monograph have been included in a list of interactions that should be considered "high-priority" for inclusion and should not be inactivated in EHR systems. This DDI subset was vetted by an expert panel commissioned by the U.S. Office of the National Coordinator (ONC) for Health Information Technology.	AGRYLIN, ANAGRELIDE HCL
Selected Quinolones/Selected Class IA & III Antiarrhythmics SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Unknown. Possibly additive or synergistic effects on the QTc interval.(1-7) Proposed mechanisms for this interaction may stem from quinolone inhibition of hepatic cytochromes and/or competitive inhibition of renal elimination via active tubular secretion.(2-7) Norfloxacin is a moderate CYP3A4 inhibitor. Amiodarone, disopyramide, and dronedarone are CYP3A4 substrates. CLINICAL EFFECTS: Increased QTc intervals which may result in potentially life-threatening arrhythmias such as torsades de pointes. PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(1) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(1) PATIENT MANAGEMENT: The manufacturers of gatifloxacin,(2) gemifloxacin,(3) lomefloxacin,(4), norfloxacin(5) and ofloxacin(6) state that these agents should be avoided in patients receiving Class IA and III antiarrhythmic agents. If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Gatifloxacin,(2) gemifloxacin,(3) lomefloxacin,(4), norfloxacin(5) and ofloxacin(6) have the potential to prolong the QTc interval. Torsades de pointes has been reported during post-marketing surveillance in patients receiving lomefloxacin.(4) A pharmacokinetic and pharmacodynamic study evaluated the interaction between ofloxacin and procainamide. Nine healthy volunteers randomly received one dose of procainamide 1 G, including or excluding pretreatment with ofloxacin (400 mg b.i.d. for 5 doses). A 12-point EKG monitored for any pharmacodynamic abnormalities and blood urine samples evaluated for pharmacokinetic variations. The AUC and Cmax for procainamide were increased by 27% and 21% with clearance diminished by 22%.(7)	AMIODARONE HCL, AMIODARONE HCL-D5W, DISOPYRAMIDE PHOSPHATE, MULTAQ, NEXTERONE, NORPACE, NORPACE CR, PACERONE
Cholera Vaccine Live/Selected Antibiotics SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Antibiotics with activity against Vibrio cholerae may attenuate the immunization response to the live cholera vaccine.(1) CLINICAL EFFECTS: Concurrent or recent antibiotic use may make the cholera vaccine ineffective.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The manufacturer of live cholera vaccine states that it should not be administered to patients who have received antibiotics within 14 days prior to vaccination.(1) If antimalarial prophylaxis with chloroquine is required, administer the live cholera vaccine at least 10 days before beginning chloroquine.(1) Antibiotics linked to this monograph are: macrolides, quinolones, tetracyclines, ampicillin, cefprozil, chloramphenicol, furazolidone, sulfamethoxazole-trimethoprim, and sulfametrole-trimethoprim.(2,3) DISCUSSION: Antibiotics with activity against Vibrio cholerae may attenuate the immunization response to the live cholera vaccine, rendering the vaccine ineffective.	VAXCHORA ACTIVE COMPONENT, VAXCHORA VACCINE
Aminolevulinic Acid/Selected Photosensitizers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Aminolevulinic acid, anthralin, coal tar and derivatives, fluoroquinolones, griseofulvin, organic staining dyes (such as methylene blue, rose bengal, or toluidine blue), phenothiazines, selected NSAIDs (such as diclofenac, ketoprofen, nabumetone, naproxen, piroxicam, and tiaprofenic acid), St. John's wort, sulfonamides, sulfonylureas, tetracyclines, and thiazides are all known photosensitizers.(1) CLINICAL EFFECTS: Concurrent use of aminolevulinic acid in patients taking anthralin, coal tar and derivatives, fluoroquinolones, griseofulvin, organic staining dyes (such as methylene blue, rose bengal, or toluidine blue), phenothiazines, selected NSAIDs (such as diclofenac, ketoprofen, nabumetone, naproxen, piroxicam, and tiaprofenic acid), St. John's wort, sulfonamides, sulfonylureas, tetracyclines, and thiazides may increase the risk of phototoxicity.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The US manufacturer states that aminolevulinic acid should be avoided in patients receiving photosensitizers including anthralin, coal tar and derivatives, fluoroquinolones, griseofulvin, organic staining dyes (such as methylene blue, rose bengal, or toluidine blue), phenothiazines, selected NSAIDs (such as diclofenac, ketoprofen, nabumetone, naproxen, piroxicam, and tiaprofenic acid), St. John's wort, sulfonamides, sulfonylureas, tetracyclines, and thiazides for 24 hours before and after administration of aminolevulinic acid.(1) DISCUSSION: Because of the risk of increased photosensitivity, the US manufacturer states that aminolevulinic acid should be avoided in patients receiving photosensitizers including anthralin, coal tar and derivatives, fluoroquinolones, griseofulvin, organic staining dyes (such as methylene blue, rose bengal, or toluidine blue), phenothiazines, selected NSAIDs (such as diclofenac, ketoprofen, nabumetone, naproxen, piroxicam, and tiaprofenic acid), St. John's wort, sulfonamides, sulfonylureas, tetracyclines, and thiazides for 24 hours before and after administration of aminolevulinic acid.(1)	AMINOLEVULINIC ACID HCL, GLEOLAN
Porfimer/Selected Photosensitizers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Porfimer causes photosensitivity due to residual drug which is present in all parts of the skin. Anthralin, coal tar and derivatives, fluoroquinolones, griseofulvin, organic staining dyes (such as methylene blue, rose bengal, or toluidine blue), phenothiazines, selected NSAIDs (such as diclofenac, ketoprofen, nabumetone, naproxen, piroxicam, and tiaprofenic acid), St. John's wort, sulfonamides, sulfonylureas, tetracyclines, and thiazides are other known photosensitizers.(1) CLINICAL EFFECTS: Concurrent use of porfimer in patients taking anthralin, coal tar and derivatives, fluoroquinolones, griseofulvin, organic staining dyes (such as methylene blue, rose bengal, or toluidine blue), phenothiazines, selected NSAIDs (such as diclofenac, ketoprofen, nabumetone, naproxen, piroxicam, and tiaprofenic acid), St. John's wort, sulfonamides, sulfonylureas, tetracyclines, and thiazides may increase the risk of phototoxicity.(1) PREDISPOSING FACTORS: Patients with any hepatic impairment and patients with severe renal impairment have reduced drug elimination and may remain photosensitive for 90 days or longer.(1) PATIENT MANAGEMENT: The US manufacturer of porfimer states that concurrent use of porfimer with photosensitizers including anthralin, coal tar and derivatives, fluoroquinolones, griseofulvin, organic staining dyes (such as methylene blue, rose bengal, or toluidine blue), phenothiazines, selected NSAIDs (such as diclofenac, ketoprofen, nabumetone, naproxen, piroxicam, and tiaprofenic acid), St. John's wort, sulfonamides, sulfonylureas, tetracyclines, and thiazides should be avoided.(1) Since the photosensitive effect of porfimer may persist for at least 30 days (and for 90 days in some patients), it would be prudent to avoid other photosensitizing agents for at least 30 days after administration of porfimer. DISCUSSION: All patients who have received porfimer become photosensitive. It is unknown what the risk of photosensitivity reactions is when porfimer is used concurrently with other photosensitizing agents. When porfimer was used in clinical trials, photosensitivity reactions occurred in about 20% of cancer patients and in 69% of high-grade dysplasia in Barretts esophagus patients. Most of the reactions were mild to moderate erythema, but they also included swelling, pruritus, burning sensation, feeling hot, or blisters. The majority of reactions occurred within 90 days of porfimer administration.(1)	PHOTOFRIN
Levoketoconazole/Possible QT Prolonging Agents SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Levoketoconazole has been observed to prolong the QTc interval in a dose-dependent manner. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of levoketoconazole with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: The US manufacturer of levoketoconazole states that levoketoconazole is contraindicated with other agents that prolong the QT interval.(1) Levoketoconazole is also contraindicated in patients with a prolonged QTcF interval of greater than 470 msec at baseline, history of torsades de pointes, ventricular tachycardia, ventricular fibrillation, or long QT syndrome (including first-degree family history). Use caution in patients with other risk factors for QT prolongation including congestive heart failure, bradyarrhythmias, and uncorrected electrolyte abnormalities. Consider more frequent ECG monitoring. Prior to starting levoketoconazole, obtain a baseline ECG and correct hypokalemia or hypomagnesemia. If a patient develops QT prolongation with a QTc interval greater than 500 msec, temporarily discontinue levoketoconazole. After resolution of prolonged QTc interval, levoketoconazole may be resumed at a lower dose. If QTc interval prolongation recurs, permanently discontinue levoketoconazole.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: During phase 1 and 2 studies, which excluded patients with baseline QTcF interval greater than 470 msec, 4 (2.4%) patients experienced QTcF > 500 msec, and 23 (14.7%) patients experienced change-from-baseline QTcF > 60 msec.(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(3)	RECORLEV
Methoxsalen/Selected Photosensitizers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Methoxsalen causes photosensitivity due to residual drug which is present in all parts of the skin from photopheresis. Anthralin, coal tar and derivatives, fluoroquinolones, griseofulvin, organic staining dyes (such as methylene blue, rose bengal, or toluidine blue), phenothiazines, selected NSAIDs (such as diclofenac, ketoprofen, nabumetone, naproxen, piroxicam, and tiaprofenic acid), St. John's wort, sulfonamides, sulfonylureas, tetracyclines, and thiazides are other known photosensitizers.(1) CLINICAL EFFECTS: Concurrent use of methoxsalen in patients taking anthralin, coal tar and derivatives, fluoroquinolones, griseofulvin, organic staining dyes (such as methylene blue, rose bengal, or toluidine blue), phenothiazines, selected NSAIDs (such as diclofenac, ketoprofen, nabumetone, naproxen, piroxicam, and tiaprofenic acid), St. John's wort, sulfonamides, sulfonylureas, tetracyclines, and thiazides may increase the risk of phototoxicity.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The US manufacturer of methoxsalen states that concurrent use of methoxsalen with anthralin, coal tar and derivatives, fluoroquinolones, griseofulvin, organic staining dyes (such as methylene blue, rose bengal, or toluidine blue), phenothiazines, selected NSAIDs (such as diclofenac, ketoprofen, nabumetone, naproxen, piroxicam, and tiaprofenic acid), St. John's wort, sulfonamides, sulfonylureas, tetracyclines, and thiazides should be avoided.(1) DISCUSSION: All patients who have received methoxsalen become photosensitive. It is unknown what the risk of photosensitivity reactions is when methoxsalen is used concurrently with other photosensitizing agents.(1)	METHOXSALEN, UVADEX
Fecal Microbiota Spores/Antibiotics SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Fecal microbiota spores is a suspension of live bacterial spores, which may be compromised by concurrent use of antibiotics.(1) CLINICAL EFFECTS: Antibiotics may decrease the effectiveness of fecal microbiota spores.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Antibiotics should not be used concurrently with fecal microbiota spores. Antibacterial treatment should be completed for 2 to 4 days before initiating treatment with fecal microbiota spores.(1) DISCUSSION: Antibiotics may compromise the effectiveness of fecal microbiota spores.	VOWST

There are 97 moderate interactions. The clinician should assess the patient’s characteristics and take action as needed. Actions required for moderate interactions include, but are not limited to, discontinuing one or both agents, adjusting dosage, altering administration.

Drug Interaction	Drug Names
Quinolones, Oral/Sucralfate SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Sucralfate decreases the absorption of certain quinolones. The probable mechanism is quinolone chelation with the aluminum contained in sucralfate. CLINICAL EFFECTS: The pharmacologic effects of certain quinolones may be decreased. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Avoid the concomitant administration of sucralfate and an oral quinolone. If an oral quinolone is administered during sucralfate therapy, the antibiotic should be administered at least two hours before sucralfate. Differences in gastric emptying time may impact the the effectiveness of spacing the administration times in some patients. DISCUSSION: Sucralfate has been shown to extensively decrease the bioavailability of ciprofloxacin (87.5-95.7% decrease in area-under-curve, AUC), lomefloxacin (51% decrease in AUC), norfloxacin (91% decrease in AUC), and ofloxacin (61% decrease in AUC), as well as the urinary concentration of norfloxacin when the agents were administered at the same time.	CARAFATE, SUCRALFATE
Arsenic/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Arsenic has been shown to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of arsenic with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of torsade de pointes is related to the extent of QT prolongation, concomitant administration of QT prolonging drugs, a history of torsade de pointes, preexisting QT interval prolongation, congestive heart failure, use of potassium-wasting diuretics, or other conditions that result in hypokalemia or hypomagnesemia.(1) Risk may also be increased in patients with other cardiovascular disease (e.g. myocardial infarction, congenital long QT syndrome), hypocalcemia, bradycardia, female gender, or advanced age.(2) Higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: The manufacturer of arsenic trioxide states that, if possible, drugs that are known to prolong the QT interval should be discontinued prior to therapy and caution is advised during coadministration.(1) In patients who reach a QTc interval value > 450 msec in men or >460 msec in women, withhold arsenic and any other QT prolonging agents. Monitor electrolytes and correct abnormalities. After the QTc normalizes, follow manufacturer instructions concerning restarting arsenic and escalation of dosing.(1) Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(3)	ARSENIC TRIOXIDE, TRISENOX
Moxifloxacin/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Moxifloxacin has been shown to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of moxifloxacin with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(3) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(3) PATIENT MANAGEMENT: The manufacturer of moxifloxacin states that moxifloxacin should be avoided in patients taking agents known to prolong the QT interval.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(2)	AVELOX IV, MOXIFLOXACIN, MOXIFLOXACIN HCL
Propafenone/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Propafenone has been shown to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of propafenone with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(3) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(3) PATIENT MANAGEMENT: The manufacturer of propafenone states that the use of propafenone with other agents known to prolong the QT interval should be avoided.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(2)	PROPAFENONE HCL, PROPAFENONE HCL ER
Levomethadone; Methadone/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Levomethadone and methadone have been shown to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1,2) CLINICAL EFFECTS: The concurrent use of levomethadone or methadone with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1,2) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(3) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(3) PATIENT MANAGEMENT: Concurrent use of levomethadone or methadone with other agents known to prolong the QT interval should be approached with extreme caution.(1,2) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(3) Most cases of methadone-induced QT prolongation are associated with, but not limited to, higher dose treatment (greater than 200 mg daily) and most involve patients being treated for pain with large, multiple daily doses. Cases have been reported in patients treated with doses commonly used for maintenance treatment of opioid addiction.(2) Levomethadone should be used with caution in patients with a history of QT prolongation, advanced heart disease, concomitant CYP3A4 inhibitors, or electrolyte abnormalities. Cases of QT prolongation and torsades de pointes have been reported, most commonly with high doses.(1)	DISKETS, METHADONE HCL, METHADONE HCL-0.9% NACL, METHADONE HCL-NACL, METHADONE INTENSOL, METHADOSE
Selected Antidiabetic Agents/Selected Quinolones SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: The exact mechanism is unknown. CLINICAL EFFECTS: Concurrent use of quinolones and antidiabetic agents may result in severe hypoglycemia.(1-7) Hypoglycemia can lead to coma. PREDISPOSING FACTORS: Elderly patients, especially those with decreased renal function may be predisposed to this interaction.(5) PATIENT MANAGEMENT: Patients maintained on antidiabetic agents who require concurrent therapy with a quinolone should be closely monitored for hypoglycemia.(1-4) Patients should be instructed to discontinue quinolone use and contact their doctor if hypoglycemia occurs.(2,4) Signs of hypoglycemia may include confusion, dizziness, feeling shaky, unusual hunger, headaches, irritability, pounding heart or very fast pulse, pale skin, sweating, trembling, weakness, or unusual anxiety. DISCUSSION: Hypoglycemia has been reported with concurrent ciprofloxacin and glyburide,(1,8,9) levofloxacin and glyburide,(2,10,11) norfloxacin and glyburide,(3) levofloxacin and glipizide (12) as well as levofloxacin and metformin-glibenclamide.(14) There has been one report of fatal hypoglycemia with concurrent levofloxacin and glyburide(9) and one of the above reports of hypoglycemia with concurrent levofloxacin and glyburide resulted in hypoxic brain injury.(11) A review of postmarketing adverse event data for the fluoroquinolones and hypoglycemic coma identified 56 reports in FAERS search from October 1987- April 2017 and 11 additional cases in the medical literature. Most patients had risk factors for hypoglycemia. 41 patients were taking one or more hypoglycemic drugs. 13 deaths occurred (some of these patients had renal insufficiency). 9 patients did not fully recover and had resultant disability.(13)	ACARBOSE, ACTOPLUS MET, ACTOS, ADMELOG, ADMELOG SOLOSTAR, AFREZZA, ALOGLIPTIN-PIOGLITAZONE, APIDRA, APIDRA SOLOSTAR, BASAGLAR KWIKPEN U-100, BASAGLAR TEMPO PEN U-100, BYDUREON BCISE, DUETACT, EXENATIDE, FIASP, FIASP FLEXTOUCH, FIASP PENFILL, FIASP PUMPCART, GLIMEPIRIDE, GLIPIZIDE, GLIPIZIDE ER, GLIPIZIDE XL, GLIPIZIDE-METFORMIN, GLUCOTROL XL, GLYBURIDE, GLYBURIDE MICRONIZED, GLYBURIDE-METFORMIN HCL, HUMALOG, HUMALOG JUNIOR KWIKPEN, HUMALOG KWIKPEN U-100, HUMALOG KWIKPEN U-200, HUMALOG MIX 50-50 KWIKPEN, HUMALOG MIX 75-25, HUMALOG MIX 75-25 KWIKPEN, HUMALOG TEMPO PEN U-100, HUMULIN R U-500, HUMULIN R U-500 KWIKPEN, INSULIN ASPART, INSULIN ASPART FLEXPEN, INSULIN ASPART PENFILL, INSULIN ASPART PROT MIX 70-30, INSULIN DEGLUDEC, INSULIN DEGLUDEC PEN (U-100), INSULIN DEGLUDEC PEN (U-200), INSULIN GLARGINE MAX SOLOSTAR, INSULIN GLARGINE SOLOSTAR, INSULIN GLARGINE-YFGN, INSULIN LISPRO, INSULIN LISPRO JUNIOR KWIKPEN, INSULIN LISPRO KWIKPEN U-100, INSULIN LISPRO PROTAMINE MIX, LANTUS, LANTUS SOLOSTAR, LIRAGLUTIDE, LYUMJEV, LYUMJEV KWIKPEN U-100, LYUMJEV KWIKPEN U-200, LYUMJEV TEMPO PEN U-100, MIGLITOL, MOUNJARO, MYXREDLIN, NATEGLINIDE, NOVOLOG, NOVOLOG FLEXPEN, NOVOLOG MIX 70-30, NOVOLOG MIX 70-30 FLEXPEN, NOVOLOG PENFILL, OSENI, OZEMPIC, PIOGLITAZONE HCL, PIOGLITAZONE-GLIMEPIRIDE, PIOGLITAZONE-METFORMIN, PRECOSE, REPAGLINIDE, REZVOGLAR KWIKPEN, RYBELSUS, SAXENDA, SEMAGLUTIDE, SEMGLEE (YFGN), SEMGLEE (YFGN) PEN, SOLIQUA 100-33, SYMLINPEN 120, SYMLINPEN 60, TOUJEO MAX SOLOSTAR, TOUJEO SOLOSTAR, TRESIBA, TRESIBA FLEXTOUCH U-100, TRESIBA FLEXTOUCH U-200, TRULICITY, VICTOZA 2-PAK, VICTOZA 3-PAK, WEGOVY, XULTOPHY 100-3.6, ZEPBOUND
Quinolones/Corticosteroids SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Quinolone-induced arthropathy is a class effect of the quinolones.(1) Exactly how corticosteroid use increases the risk of tendon rupture is unknown. CLINICAL EFFECTS: Concurrent use of quinolones and corticosteroids may increase the risk of tendonitis and/or tendon rupture. This affect is most common in the Achilles tendon, but has been reported in the rotator cuff (shoulder), hand, biceps, thumb, and other tendons.(2-9) PREDISPOSING FACTORS: Risk factors for tendinitis and tendon rupture include age greater than 60; a history of kidney, heart, or lung transplantation, strenuous physical activity, renal failure, and previous tendon disorders such as rheumatoid arthritis. PATIENT MANAGEMENT: Quinolone use should be discontinued if the patient experiences pain, inflammation, or rupture of a tendon. Patients should be instructed to rest and refrain from exercise until the diagnosis of tendonitis tendon rupture has been excluded.(2-9) DISCUSSION: Ruptures of the shoulder, hand, Achilles tendon, or other tendons that required surgical repair or resulted in prolonged disability have been reported in patients receiving ciprofloxacin,(2) gatifloxacin,(3) levofloxacin,(4) lomefloxacin,(5) moxifloxacin,(6) nalidixic acid,(7) norfloxacin,(8) and ofloxacin.(9) A retrospective review of the IMS Health database examined quinolone use use from July 1, 1992 to June 30, 1998. The adjusted relative risk of tendon disorder with concurrent quinolone use was 1.9. Relative risk increased to 3.2 in patients aged 60 or older compared to 0.9 in patients aged less than 60. In patients aged 60 or older who used corticosteroids and quinolones concurrently, relative risk increased to 6.2.(10) In contrast, another retrospective review examined patients from a health insurance claims database and found no apparent effect from concurrent quinolone and corticosteroid use.(11) In a review of the follow-up to 42 spontaneously reported case of quinolone-associated tendon disorders in the Netherlands between January, 1988 and January, 1998, risk factors for tendon disorders included age older than 60, oral corticosteroid use, and existing joint problems.(12) In a review of the Swiss Drug Monitoring system, four of seven cases of levofloxacin-associated tendon problems also involved concurrent oral or inhaled corticosteroids.(13) In a review of the Medline database from 1966-2001, 98 case reports of tendinopathy associated with quinolones were located. Thirty-two (32.7%) of the patients had received systemic or inhaled corticosteroids before and during quinolone therapy. Of the 40 patients who suffered a tendon rupture, 21 (52.5%) were receiving corticosteroids.(14) Other authors have reported cases of tendon disorders in patients receiving concurrent corticosteroids and ciprofloxacin,(15) levofloxacin, (16-20) and ofloxacin.(21)	ADVAIR DISKUS, ADVAIR HFA, AGAMREE, AIRDUO DIGIHALER, AIRDUO RESPICLICK, AIRSUPRA, ALDOSTERONE, ALKINDI SPRINKLE, ALVESCO, ANUCORT-HC, ANUSOL-HC, ARMONAIR DIGIHALER, ARNUITY ELLIPTA, ASMANEX, ASMANEX HFA, BECLOMETHASONE DIPROPIONATE, BETA 1, BETALOAN SUIK, BETAMETHASONE ACETATE MICRO, BETAMETHASONE ACETATE-SOD PHOS, BETAMETHASONE DIPROPIONATE, BETAMETHASONE SOD PHOS-ACETATE, BETAMETHASONE SOD PHOS-WATER, BETAMETHASONE SODIUM PHOSPHATE, BETAMETHASONE VALERATE, BREO ELLIPTA, BREYNA, BREZTRI AEROSPHERE, BSP 0820, BUDESONIDE, BUDESONIDE DR, BUDESONIDE EC, BUDESONIDE ER, BUDESONIDE MICRONIZED, BUDESONIDE-FORMOTEROL FUMARATE, BUPIVACAINE-DEXAMETH-EPINEPHRN, CELESTONE, CLOBETASOL PROPIONATE MICRO, CORTEF, CORTENEMA, CORTIFOAM, CORTISONE ACETATE, DEFLAZACORT, DEPO-MEDROL, DESONIDE MICRONIZED, DESOXIMETASONE, DESOXYCORTICOSTERONE ACETATE, DEXABLISS, DEXAMETHASONE, DEXAMETHASONE ACETATE, DEXAMETHASONE ACETATE MICRO, DEXAMETHASONE INTENSOL, DEXAMETHASONE ISONICOTINATE, DEXAMETHASONE MICRONIZED, DEXAMETHASONE SOD PHOS-WATER, DEXAMETHASONE SODIUM PHOSPHATE, DEXAMETHASONE-0.9% NACL, DMT SUIK, DOUBLEDEX, DULERA, EMFLAZA, EOHILIA, FLUDROCORTISONE ACETATE, FLUNISOLIDE, FLUOCINOLONE ACETONIDE, FLUOCINOLONE ACETONIDE MICRO, FLUOCINONIDE MICRONIZED, FLUTICASONE PROPIONATE, FLUTICASONE PROPIONATE HFA, FLUTICASONE PROPIONATE MICRO, FLUTICASONE-SALMETEROL, FLUTICASONE-SALMETEROL HFA, FLUTICASONE-VILANTEROL, HEMADY, HEMMOREX-HC, HEXATRIONE, HYDROCORTISONE, HYDROCORTISONE ACETATE, HYDROCORTISONE SOD SUCCINATE, HYDROCORTISONE-PRAMOXINE, KENALOG-10, KENALOG-40, KENALOG-80, LIDOCIDEX-I, MAS CARE-PAK, MEDROL, MEDROLOAN II SUIK, MEDROLOAN SUIK, METHYLPREDNISOLONE, METHYLPREDNISOLONE AC MICRO, METHYLPREDNISOLONE ACETATE, METHYLPREDNISOLONE SODIUM SUCC, MILLIPRED, MILLIPRED DP, MOMETASONE FUROATE, ORAPRED ODT, ORTIKOS, PEDIAPRED, PREDNISOLONE, PREDNISOLONE ACETATE MICRONIZE, PREDNISOLONE MICRONIZED, PREDNISOLONE SODIUM PHOS ODT, PREDNISOLONE SODIUM PHOSPHATE, PREDNISONE, PREDNISONE INTENSOL, PREDNISONE MICRONIZED, PRO-C-DURE 5, PRO-C-DURE 6, PROCTOCORT, PULMICORT, PULMICORT FLEXHALER, QVAR REDIHALER, RAYOS, SOLU-CORTEF, SOLU-MEDROL, SYMBICORT, TAPERDEX, TARPEYO, TRELEGY ELLIPTA, TRIAMCINOLONE, TRIAMCINOLONE ACETONIDE, TRIAMCINOLONE DIACETATE, TRIAMCINOLONE DIACETATE MICRO, TRILOAN II SUIK, TRILOAN SUIK, UCERIS, VERIPRED 20, WIXELA INHUB, ZCORT, ZILRETTA
Haloperidol/QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Torsades de pointes has been reported with haloperidol. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1-3) CLINICAL EFFECTS: The concurrent use of haloperidol with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1-3) PREDISPOSING FACTORS: The risk of QT prolongation may be increased by: hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, use of multiple medications, intravenous haloperidol, or higher than recommended dosages of haloperidol. The risk of QT prolongation or torsade de pointes may also be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), bradycardia, or advanced age.(5) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(5) PATIENT MANAGEMENT: The Australian,(1) UK(2) and US(3) manufacturers of haloperidol state that haloperidol should be used with caution when given with other agents known to prolong the QT interval. If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Sudden death, QT-prolongation, and torsades de pointes have been reported with haloperidol.(3) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(4) One or more of the drug pairs linked to this monograph have been included in a list of interactions that should be considered "high-priority" for inclusion and should not be inactivated in EHR systems. This DDI subset was vetted by an expert panel commissioned by the U.S. Office of the National Coordinator (ONC) for Health Information Technology.	HALDOL DECANOATE 100, HALDOL DECANOATE 50, HALOPERIDOL, HALOPERIDOL DECANOATE, HALOPERIDOL DECANOATE 100, HALOPERIDOL LACTATE
Levofloxacin/QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Concurrent use of levofloxacin and agents known to prolong the QT interval may result in additive or synergistic effects on the QTc Interval.(1) CLINICAL EFFECTS: Concurrent administration may result in prolongation of the QTc interval and life-threatening cardiac arrhythmias, including torsades de pointes. PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(3) Concurrent use of more than one drug know to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(3) PATIENT MANAGEMENT: The U.S. manufacturer of levofloxacin states that levofloxacin should be used with caution when given with other agents known to prolong the QT interval.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(2) One or more of the drug pairs linked to this monograph have been included in a list of interactions that should be considered "high-priority" for inclusion and should not be inactivated in EHR systems. This DDI subset was vetted by an expert panel commissioned by the U.S. Office of the National Coordinator (ONC) for Health Information Technology.	LEVOFLOXACIN, LEVOFLOXACIN HEMIHYDRATE, LEVOFLOXACIN-D5W
Thioridazine/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Thioridazine has been shown to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of thioridazine with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: Hypokalemia, bradycardia, the presence of congenital prolongation of the QT interval, or use of thioridazine in patients with reduced CYP2D6 activity (either through genetic predisposition or use of drugs that inhibit CYP2D6 activity) may increase the risk of torsades de pointes and/or sudden death in patients taking thioridazine.(1) The risk of QT prolongation or torsade de pointes may also be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes), hypomagnesemia, hypocalcemia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: The manufacturer of thioridazine states under contraindications that the use of thioridazine should be avoided in combination with other drugs that are known to prolong the QTc interval.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Agents that are linked to this monograph may have been associated with Torsades de Pointes and/or QT prolongation but at this time lack substantial evidence for causing Torsades de Pointes.(4) One or more of the drug pairs linked to this monograph have been included in a list of interactions that should be considered "high-priority" for inclusion and should not be inactivated in EHR systems. This DDI subset was vetted by an expert panel commissioned by the U.S. Office of the National Coordinator (ONC) for Health Information Technology.	THIORIDAZINE HCL, THIORIDAZINE HYDROCHLORIDE
Oral Fluoroquinolones/Sevelamer SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Sevelamer may bind to oral fluoroquinolones, preventing its absorption.(1) CLINICAL EFFECTS: Simultaneous administration of sevelamer may result in decreased levels and clinical effectiveness of oral fluoroquinolones.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: If concurrent therapy is warranted, the oral fluoroquinolone should be administered at least two hours before or six hours after sevelamer.(2) DISCUSSION: In a study in 15 subjects, simultaneous administration of ciprofloxacin (750 mg) and sevelamer (seven 403 mg capsules) decreased the bioavailability of ciprofloxacin by 48%.(1,2) Oral fluoroquinolones linked to this monograph are: balofloxacin, cinoxacin, ciprofloxacin, delafloxacin, enoxacin, fleroxacin, flumequine, gatifloxacin, grepafloxacin, levofloxacin, lomefloxacin, moxifloxacin, nadifloxacin, nalidixic acid, nitroxoline, norfloxacin, ofloxacin, pefloxacin, pipemidic acid, prulifloxacin, rosoxacin, sparfloxacin, temafloxacin, tosufloxacin, and trovafloxacin.	RENVELA, SEVELAMER CARBONATE, SEVELAMER HCL
Ivabradine/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: QT prolongation may be exacerbated by ivabradine-induced reduction in heart rate.(1) CLINICAL EFFECTS: Concurrent use of ivabradine and agents known to prolong the QT interval may exacerbate QT prolongation.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(3) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(3) PATIENT MANAGEMENT: The UK, AU, and Canadian manufacturer of ivabradine states that concurrent use with cardiovascular and non-cardiovascular QT prolonging agents should be avoided.(1) The Canadian manufacturer states that if concurrent therapy is deemed necessary, close cardiac monitoring (12-lead ECG) is required. Depending on the ECG results, ivabradine dosing may need to be decreased or stopped.(4) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Agents that are linked to this monograph may have been associated with torsades de pointes and/or QT prolongation but at this time lack substantial evidence for causing torsades de pointes.(2)	CORLANOR, IVABRADINE HCL
Ranolazine/QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Ranolazine prolongs the QTc interval in a dose-related manner. Use with other agents that prolong the QTc interval may result in additive effects.(1) CLINICAL EFFECTS: Concurrent use of ranolazine and agents known to prolong the QTc interval may result in prolongation of the QTc interval and life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(4) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(4) PATIENT MANAGEMENT: The UK manufacturer of ranolazine states that concurrent use with agents known to prolong the QT interval should be approached with caution.(1) Patients should be instructed to inform their physician if they are receiving any drugs that prolong the QTc interval.(2) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Ranolazine has been shown to prolong the QTc interval in a dose-related manner.(1,2) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(3)	ASPRUZYO SPRINKLE, RANOLAZINE ER
Posaconazole/QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Concurrent use of posaconazole and agents known to prolong the QT interval may result in additive or synergistic effects on the QTc Interval.(1) CLINICAL EFFECTS: Concurrent administration may result in prolongation of the QTc interval and life-threatening cardiac arrhythmias, including torsades de pointes. PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(3) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(3) PATIENT MANAGEMENT: The UK manufacturer of posaconazole states that posaconazole should be used with caution when given with other agents known to prolong the QT interval.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(2)	NOXAFIL, POSACONAZOLE
Dasatinib/QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Concurrent use of dasatinib and agents known to prolong the QT interval may result in additive or synergistic effects on the QTc interval.(1) CLINICAL EFFECTS: Concurrent administration may result in prolongation of the QTc interval and life-threatening cardiac arrhythmias, including torsades de pointes. PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(3) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(3) PATIENT MANAGEMENT: The US manufacturer of dasatinib states that dasatinib should be used with caution when given with other agents known to prolong the QT interval.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: A retrospective review of 618 cancer patients treated with 902 administrations of tyrosine kinase inhibitors were evaluated for rate and incidence of QTc prolongation. In patients who received dasatinib, QTc prolongation was identified in 48 (41.7%) with 8 (16.7%) having Grade 1 (QTc 450-480 ms) and 15 (31.3%) having Grade 2 (QTc 480-500 ms). Grade 3 events occurred in 8 (16.7%) having QTc greater than or equal to 500 ms and 14 (29.2%) having QTc change greater than or equal to 60 ms. Ventricular tachycardia was seen in 2 (4.2%) of patients and 1 (2.1%) patient experienced TdP.(4) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(2)	DASATINIB, SPRYCEL
Paliperidone/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Paliperidone has been shown to cause a modest increase in the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1,2) CLINICAL EFFECTS: The concurrent use of paliperidone with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1,2) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(4) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(4) PATIENT MANAGEMENT: The US manufacturer of paliperidone states that the use of paliperidone should be avoided with other drugs that are known to prolong the QTc interval, including Class IA and Class III antiarrhythmics, antipsychotics, antibiotics such as gatifloxacin and moxifloxacin, or any other class of medications known to prolong the QTc interval.(1,2) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Agents that are linked to this monograph may have been associated with torsades de pointes and/or QT prolongation but at this time lack substantial evidence for causing torsades de pointes.(3)	ERZOFRI, INVEGA, INVEGA HAFYERA, INVEGA SUSTENNA, INVEGA TRINZA, PALIPERIDONE ER
Lapatinib/QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Concurrent use of lapatinib and agents known to prolong the QT interval may result in additive or synergistic effects on the QTc interval.(1) CLINICAL EFFECTS: Concurrent administration may result in prolongation of the QTc interval and life-threatening cardiac arrhythmias, including torsades de pointes. PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(3) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(3) PATIENT MANAGEMENT: The US manufacturer of lapatinib states that lapatinib should be used with caution when given with other agents known to prolong the QT interval.(1) If concurrent therapy is warranted, obtain serum calcium, magnesium, and potassium levels and monitor ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Lapatinib is associated with concentration-dependent QTc interval prolongation. In a single-blind, placebo-controlled crossover study with lapatinib 2,000 mg every 12 hours for 3 doses, a maximum mean double delta QTcF of 8.75 ms was observed. Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(2)	LAPATINIB, TYKERB
Nilotinib/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Nilotinib prolongs the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1,3) CLINICAL EFFECTS: The concurrent use of nilotinib with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1,3) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(4) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(4) PATIENT MANAGEMENT: The US manufacturer of nilotinib states that the use of nilotinib should be avoided with other drugs that are known to prolong the QTc interval. Should treatment with a QT prolonging agent be required, interruption of nilotinib therapy should be considered. The UK manufacturer of nilotinib states that the use of nilotinib should be used with caution with other drugs that are known to prolong the QTc interval.(3) Patient monitoring recommendations: If concurrent therapy cannot be avoided, monitor patients closely for prolongation of the QT interval and follow recommended nilotinib dosage adjustments for QT prolongation.(1) Consider obtaining serum calcium, magnesium, and potassium levels at baseline and regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: A retrospective review of 618 cancer patients treated with 902 administrations of tyrosine kinase inhibitors were evaluated for rate and incidence of QTc prolongation. In patients who received nilotinib, QTc prolongation was identified in 29 (38.7%) with 1 (3.5%) having Grade 1 (QTc 450-480 ms) and 2 (7%) having Grade 2 (QTc 480-500 ms). Grade 3 events occurred in 9 (31%) having QTc greater than or equal to 500 ms and 17 (58.6%) having QTc change greater than or equal to 60 ms. No patients developed ventricular tachycardia, sudden cardiac death, or TdP.(5) Agents that are linked to this monograph may have been associated with torsades de pointes and/or QT prolongation but at this time lack substantial evidence for causing torsades de pointes.(2)	DANZITEN, NILOTINIB HCL, TASIGNA
Quinine/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Quinine has been shown to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of quinine with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(3) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, and/or renal/hepatic dysfunction).(3) PATIENT MANAGEMENT: The US manufacturer of quinine states that concurrent use with agents known to prolong the QT interval should be avoided.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.	QUALAQUIN, QUININE HCL, QUININE SULFATE
Toremifene/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Toremifene has been shown to prolong the QTc interval in a dose-related and concentration-related manner.(1) Concurrent use of toremifene and agents known to prolong the QT interval may result in additive or synergistic effects on the QTc interval.(1,2) CLINICAL EFFECTS: Concurrent administration may result in prolongation of the QTc interval and life-threatening cardiac arrhythmias, including torsades de pointes.(1,2) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(4) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, and/or renal/hepatic dysfunction).(4) PATIENT MANAGEMENT: The US manufacturer of toremifene states that concurrent use should be avoided. If treatment with an agent known to prolong the QT interval is required, toremifene therapy should be interrupted. If it is not possible to interrupt toremifene therapy, electrocardiograms (ECGs) should be obtained and patients should be closely monitored for QT prolongation.(1) Additional monitoring when concurrent therapy is warranted: consider obtaining serum calcium, magnesium, and potassium levels at baseline and regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. The UK manufacturer of toremifene states that the use of other drugs that are known to prolong the QTc interval is contraindicated. These agents include class IA and III antiarrhythmics, astemizole, bepridil, cisapride, diphemanil, erythromycin IV, halofantrine, haloperidol, mizolastine, moxifloxacin, pentamidine, phenothiazines, pimozide, sertindole, terfenadine, and vincamine IV.(2) DISCUSSION: Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(3)	FARESTON, TOREMIFENE CITRATE
Lopinavir/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Lopinavir has been shown to prolong the QTc interval by 5 msec. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of lopinavir with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(3) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, and/or renal/hepatic dysfunction).(3) PATIENT MANAGEMENT: The US manufacturer of lopinavir states that the concurrent administration of other drugs that are known to prolong the QTc interval should be avoided.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: In a randomized, placebo and active controlled crossover study in 39 healthy subjects designed to evaluated QTc intervals, lopinavir/ritonavir increased QTc by 5.3 msec and 15.2 msec for 400/100 mg twice daily and 800/200 mg twice daily, respectively.(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(2)	KALETRA, LOPINAVIR-RITONAVIR
Telavancin/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Telavancin has been shown to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of telavancin with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: The US manufacturer of telavancin recommends against the use of telavancin with other drugs known to cause QT prolongation.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: In a randomized, double-blind, multiple-dose, positive-controlled, placebo-controlled, parallel study in healthy subjects, the mean maximum baseline-corrected, placebo-corrected QTc prolongation was 11.6 msec and 15.1 msec for telavancin at dosages of 7.5 mg/kg and 15 mg/kg, respectively. The estimated mean maximum baseline-corrected, placebo-corrected QTc prolongation for a telavancin dosage of 10 mg/kg is 12-15 msec.(1) In studies in patients, 21% of patients receiving telavancin (214 of 1029, 10 mg/kg) and 16% of patients receiving vancomycin (164 of 1033) received concurrent QT prolonging agents. The rate of QTc prolongation greater than 60 msec was 1.5% (15 patients) in the telavancin group and 0.6% (6 patients) in the vancomycin group. Nine of the 15 telavancin subjects with QTc prolongation received concurrent QT prolongers, compared with 1 of the vancomycin patients.(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(3)	VIBATIV
Pazopanib/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Pazopanib has been shown to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of pazopanib with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(3) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, and/or renal/hepatic dysfunction).(3) PATIENT MANAGEMENT: The US manufacturer of pazopanib states that pazopanib should be avoided in patients receiving other drugs known to cause QT prolongation.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: In clinical studies, 2% (11/558) of patients receiving pazopanib experienced QT prolongation. Torsades de pointes occurred in less than 1% (2/977) of patients who received pazopanib in monotherapy studies. In a randomized clinical trial, 3 of 290 patients who received pazopanib had post-baseline QTc values between 500 and 549 msec. None of the patients receiving placebo had post-baseline QTc values greater than or equal to 500 msec.(1) A retrospective review of 618 cancer patients treated with 902 administrations of tyrosine kinase inhibitors were evaluated for rate and incidence of QTc prolongation. In patients who received pazopanib, QTc prolongation was identified in 32 (19.4%) with 18 (56.3%) having Grade 1 (QTc 450-480 ms) and 4 (12.5%) having Grade 2 (QTc 480-500 ms). Grade 3 events occurred in 3 (9.3%) having QTc greater than or equal to 500 ms and 4 (12.5%) having QTc change greater than or equal to 60 ms. Ventricular tachycardia was seen in 2 (6.3%) of patients and 1 (3.1%) patient experienced sudden cardiac death.(4) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(2)	PAZOPANIB HCL, VOTRIENT
Iloperidone/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Iloperidone has been shown to prolong the QTc interval by 9 msec at dosages of 12 mg twice daily. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of iloperidone with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, advanced age or with concurrent use of inhibitors of CYP3A4 or CYP2D6, which metabolize iloperidone.(1,3) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. co-administration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(3) PATIENT MANAGEMENT: The US manufacturer of iloperidone states that the concurrent administration of other drugs that are known to prolong the QTc interval should be avoided.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(2) Coadministration of ketoconazole (200 mg twice daily, an inhibitor of CYP P-450-3A4) and iloperidone (12 mg twice daily) was associated with a mean QTcF increase of 19 msec from baseline, compared with an increase of 9 msec with iloperidone alone.(1) Coadministration of paroxetine (20 mg daily, an inhibitor of CYP P-450-2D6) and iloperidone (12 mg twice daily) was associated with a mean QTcF increase of 19 msec from baseline, compared with an increase of 9 msec with iloperidone alone.(1)	FANAPT
Romidepsin/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Romidepsin has been shown to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of romidepsin with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: The US manufacturer of romidepsin states that appropriate cardiovascular monitoring, such as baseline and regular monitoring of ECG and obtaining serum calcium, magnesium, and potassium levels, should be performed if concurrent therapy with agents known to prolong the ECG is warranted.(1) Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: In two clinical trials, discontinuation of romidepsin secondary to QT prolongation occurred in at least 2% of patients.(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(3)	ISTODAX, ROMIDEPSIN
Ciprofloxacin/QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Ciprofloxacin has been shown to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of ciprofloxacin with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(4) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, and/or renal/hepatic dysfunction).(4) PATIENT MANAGEMENT: The US manufacturer of ciprofloxacin states that ciprofloxacin should be used with caution with other agents known to prolong the QT interval, especially in the elderly.(1) The UK manufacturer of ciprofloxacin states that ciprofloxacin should be used with caution in patients at risk for torsades.(2) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(3) One or more of the drug pairs linked to this monograph have been included in a list of interactions that should be considered "high-priority" for inclusion and should not be inactivated in EHR systems. This DDI subset was vetted by an expert panel commissioned by the U.S. Office of the National Coordinator (ONC) for Health Information Technology.	CIPRO, CIPROFLOXACIN, CIPROFLOXACIN HCL, CIPROFLOXACIN-D5W
Eribulin/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Eribulin has been shown to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of eribulin with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: The US manufacturer of eribulin states that patients receiving concurrent therapy with eribulin and other agents known to prolong the QT interval should receive ECG monitoring.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: QT prolongation, independent of eribulin concentration, was observed on Day 8 of therapy but not on Day 1 in an uncontrolled open-label ECG study in 26 patients.(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(3)	ERIBULIN MESYLATE, HALAVEN
Selected Oral Quinolones/Selected Oral Cations SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Aluminum, calcium, iron, lanthanum, magnesium, and zinc may form chelation compounds with the quinolones.(1-39) CLINICAL EFFECTS: Simultaneous administration or administration of products containing aluminum, calcium, iron, lanthanum, magnesium, and/or zinc close to the administration time of an oral quinolone may result in decreased absorption and clinical effectiveness of the quinolone. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: If possible, avoid concurrent therapy with quinolones and cation-containing products. If it is necessary to administer these agents concurrently, follow the manufacturers' recommendations regarding timing of administration of the quinolone and cation-containing products. Manufacturer recommendations regarding the separation of administration times of quinolones and products containing aluminum, calcium, iron, lanthanum, magnesium, and/or zinc vary: ---Do not give ciprofloxacin for at least 2 hours before or 6 hours after oral cations.(1) ---Do not give delafloxacin for at least 2 hours before or 6 hours after oral cations.(2) ---Do not give enoxacin for at least 2 hours before or 8 hours after oral cations.(3) ---Do not give levofloxacin for at least 2 hours before or 2 hours after oral cations.(4) ---Do not give nalidixic acid for at least 2 hours before or 2 hours after oral cations.(5) ---Do not give norfloxacin for at least 2 hours before or 2 hours after oral cations.(6) ---Do not give ofloxacin for at least 2 hours before or 2 hours after oral cations.(7) ---Do not give sparfloxacin for at least 4 hours before oral cations.(8) The US manufacturer of lanthanum recommends that quinolones be taken at least 1 hour before or 4 hours after lanthanum;(9) however, it would be prudent to follow the specific quinolone manufacturers' recommendations regarding concurrent administration of cations. For quinolones not listed above, separate their administration from oral cations by as much time as feasible. DISCUSSION: Aluminum, calcium, iron, magnesium, and zinc products have been shown to form chelation compounds with quinolone antibiotics, resulting in decreased absorption of the quinolone.(1-38) Treatment failures have been reported.(10-12) In a study in 12 healthy subjects, simultaneous administration of didanosine chewable tablets, which contain aluminum and magnesium, decreased ciprofloxacin area-under-curve (AUC) and maximum concentration (Cmax) by 92% and 98%, respectively.(13) The administration of ciprofloxacin 2 hours prior to Videx chewable/dispersible tablets decreased ciprofloxacin concentrations by 26%.(14,15) In a study in healthy subjects, pretreatment with an antacid containing aluminum-magnesium hydroxide at 5-10 minutes, 2 hours, and 4 hours before a single dose of ciprofloxacin decreased ciprofloxacin AUC by 84.9%, 76.8%, and 30%, respectively. There was no effect when the antacid was administered 6 hours before or 2 hours after.(16) In a study in 12 healthy subjects, aluminum hydroxide decreased ciprofloxacin AUC by 85%.(17) In a study in patients on continuous ambulatory peritoneal dialysis, peak levels of ciprofloxacin were decreased by 67% to 92% in patients receiving aluminum-containing antacids.(18) In a study in 15 healthy subjects, simultaneous administration of calcium acetate decreased the bioavailability of ciprofloxacin by 51%.(19) In a study in 6 healthy males, simultaneous administration of calcium carbonate decreased ciprofloxacin Cmax and AUC by 40% and 43%, respectively.(20) In a study in 12 healthy subjects, calcium carbonate decreased ciprofloxacin AUC by 40%.(17) In a study in 13 healthy males, calcium carbonate had no effect on ciprofloxacin bioavailability when administered 2 hours prior to the antibiotic.(21,22) In a study in healthy males, simultaneous administration of calcium polycarbophil decreased ciprofloxacin AUC by 50%.(23) In a study in 8 healthy males, simultaneous administration of ferrous fumarate (200 mg) decreased ciprofloxacin AUC by 70%.(24) In a study in healthy subjects, ferrous gluconate decreased ciprofloxacin bioavailability by 50%; however, no significant effects were seen with iron-ovotransferrin.(25) In a study in 8 healthy subjects, ferrous sulfate decreased the Cmax and AUC of simultaneously administered ciprofloxacin by 54% and 57%, respectively.(26) In a study in 8 healthy subjects, administration of ferrous sulfate decreased the Cmax and AUC of ciprofloxacin by 33% and 46%, respectively. Administration of ferrous gluconate decreased the Cmax and AUC of ciprofloxacin by 57% and 67%, respectively. Administration of a multivitamin product containing calcium, copper, iron, magnesium, manganese, and zinc decreased the Cmax and AUC of ciprofloxacin by 53% and 56%, respectively.(27) In a study in 12 healthy males, ferrous sulfate decreased ciprofloxacin AUC by 63%.(28) In a study in 12 healthy subjects, lanthanum carbonate decreased the area-under-curve (AUC) and maximum concentration (Cmax) of concurrently administered ciprofloxacin by 54% and 56%, respectively.(29) In a study in 12 healthy males, a multivitamin containing zinc decreased ciprofloxacin AUC by 22%.(28) In a study in 12 healthy subjects, an antacid containing aluminum-magnesium hydroxide had no effect on the pharmacokinetics of intravenous enoxacin.(30) In a study in 10 healthy subjects, administration of an aluminum-magnesium hydroxide antacid 0.5 hours or 2 hours before oral enoxacin (400 mg single dose) decreased the AUC of enoxacin by 73% and 43%, respectively. There were no significant effects on enoxacin AUC when the antacid was administered 8 hours before or 2 hours after enoxacin.(31) In a study in 9 healthy subjects, colloidal aluminum phosphate had no effect on the amount of enoxacin absorbed; however, ferrous sulfate (1050 mg) decreased the amount of enoxacin absorption by 10%.(32) In a study in 5 healthy subjects and 5 patients with cystic fibrosis, separation of levofloxacin (750 mg) and calcium carbonate (500 mg 3 times daily with meals) by 2 hours resulted in no interaction in healthy subjects; however, levofloxacin levels were not bioequivalent in patients with cystic fibrosis.(33) Concurrent magnesium-aluminum hydroxide or calcium have been shown to decrease the bioavailability of norfloxacin by 91.0% and 63.5%, respectively.(34) Concurrent zinc has been shown to decrease the bioavailability of norfloxacin.(35) In a study in 8 healthy subjects, ferrous sulfate decreased the Cmax and AUC of simultaneously administered norfloxacin by 75% and 73%, respectively.(26) Simultaneous aluminum phosphate was found to decrease the rate, but not the extent, of absorption of ofloxacin.(36) In a study in 8 healthy subjects, ferrous sulfate decreased the Cmax and AUC of simultaneously administered norfloxacin by 36% and 25%, respectively.(26) In an in vitro study, ferrous sulfate, aluminum hydroxide, and calcium carbonate decreased ofloxacin availability by 32.6%, 30.7%, and 26.2%, respectively. However, in vivo tests showed a significant effect with only aluminum hydroxide.(37) In a study in 9 healthy subjects, simultaneous administration colloidal aluminum phosphate had no effect on ofloxacin (200 mg) absorption; however, ferrous sulfate (1050 mg) decreased the ofloxacin fraction of dose absorbed by 10.85%.(32) In a study in 16 subjects, administration of either aluminum-magnesium hydroxide or calcium carbonate at least 2 hours before or after ofloxacin administration had no significant effects on ofloxacin levels.(38) The administration of an antacid containing aluminum hydroxide and magnesium hydroxide 2 hours before, 2 hours after, and 4 hours after sparfloxacin decreased sparfloxacin levels by 23%, 17%, and 5%, respectively.(39) One or more of the drug pairs linked to this monograph have been included in a list of interactions that could be considered for classification as "non-interruptive" in EHR systems. This DDI subset was vetted by an expert panel commissioned by the U.S. Office of the National Coordinator (ONC) for Health Information Technology.	ACCRUFER, ALUMINUM HYDROXIDE, AUROVELA 24 FE, AUROVELA FE, AURYXIA, BALCOLTRA, BLISOVI 24 FE, BLISOVI FE, CALCIUM ACETATE, CALCIUM CHLORIDE, CALCIUM GLUCONATE, CALCIUM GLUCONATE MONOHYDRATE, CHARLOTTE 24 FE, CLENPIQ, FEIRZA, FERRIC CITRATE, FINZALA, FOSRENOL, GALZIN, GEMMILY, HAILEY 24 FE, HAILEY FE, JOYEAUX, JUNEL FE, JUNEL FE 24, KAITLIB FE, KAOLIN, LANTHANUM CARBONATE, LARIN 24 FE, LARIN FE, LAYOLIS FE, LEVONORG-ETH ESTRAD-FE BISGLYC, LO LOESTRIN FE, LOESTRIN FE, MAGNESIUM CHLORIDE, MAGNESIUM CITRATE, MAGNESIUM OXIDE, MAGNESIUM SULFATE, MERZEE, MIBELAS 24 FE, MICROGESTIN FE, MINZOYA, NORETHIN-ETH ESTRA-FERROUS FUM, NORETHINDRONE-E.ESTRADIOL-IRON, SOD SULF-POTASS SULF-MAG SULF, SUFLAVE, SUPREP, SUTAB, TARINA 24 FE, TARINA FE, TARINA FE 1-20 EQ, TAYTULLA, TILIA FE, TRI-LEGEST FE, VELPHORO, WILZIN, WYMZYA FE, XARAH FE, XELRIA FE, ZINC ACETATE, ZINC CHLORIDE, ZINC OXIDE, ZINC SULFATE, ZINC UNDECYLENATE
Vandetanib/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Vandetanib has been shown to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of vandetanib with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(3) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(3) PATIENT MANAGEMENT: The manufacturer of vandetanib states that the use of vandetanib with other agents known to prolong the QT interval should be avoided.(1) The manufacturer of vandetanib states therapy should be interrupted if Corrected QT interval, Frederica (QTcF) is greater than 500 ms; resume at a reduced dose when the QTcF returns to less than 450 ms. Consult current prescribing information for further details.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Vandetanib has been shown to prolong the QTc interval in a dose-dependent manner. Vandetanib has a long half-life (19 days) and effects on the QTc interval may not resolve quickly following vandetanib discontinuation.(1) A retrospective review of 618 cancer patients treated with 902 administrations of tyrosine kinase inhibitors were evaluated for rate and incidence of QTc prolongation. In patients who received vandetanib, QTc prolongation was identified in 4 (80%) with 0 (0%) having Grade 1 (QTc 450-480 ms) and 1 (25%) having Grade 2 (QTc 480-500 ms). Grade 3 events occurred in 1 (25%) having QTc greater than or equal to 500 ms and 2 (50%) having QTc change greater than or equal to 60 ms. No patients had ventricular tachycardia, sudden cardiac death, or TdP.(4) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(2) One or more of the drug pairs linked to this monograph have been included in a list of interactions that should be considered "high-priority" for inclusion and should not be inactivated in EHR systems. This DDI subset was vetted by an expert panel commissioned by the U.S. Office of the National Coordinator (ONC) for Health Information Technology.	CAPRELSA
Vemurafenib/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The use of vemurafenib in patients maintained on agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: Vemurafenib should not be initiated in patients taking medications known to prolong the QT interval, patients with a baseline QTc greater than 500 msec, uncorrectable electrolyte abnormalities, or known long QT syndrome is not recommended.(1) All patients receiving vemurafenib should undergo ECG testing at baseline, after 15 days of treatment, monthly during the first 3 months of treatment, and then every 3 months. If a patient's QTc exceeds 500 msec during treatment, vemurafenib should be discontinued and cardiac risk factors for QT prolongation should be controlled. Consider discontinuing other medications known to prolong the QT interval at this time. If the patient's QTc decreases below 500 msec, vemurafenib may be introduced at a lower dosage according to the current labeling recommendations. If the patient's QTc remains greater than 500 msec and increased >60 msec from pre-treatment values after controlling cardiac risk factors for prolongation, permanently discontinue vemurafenib.(1) Consider obtaining serum calcium, magnesium, and potassium levels at baseline and regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Vemurafenib is associated with concentration-dependent QTc interval prolongation. In the first month of treatment, the largest mean QTc change was 12.8 msec (upper boundary of 90% CI: 14.9 msec). In the first 6 months of treatment, the largest mean QTc change was 15.1 msec (upper boundary of 90% CI: 17.7 msec).(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(3)	ZELBORAF
Citalopram/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1-3) CLINICAL EFFECTS: The use of citalopram in patients maintained on agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1-3) PREDISPOSING FACTORS: Higher doses of citalopram, especially doses greater than 40 mg, may increase the risk of QT prolongation. The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(4) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(4) PATIENT MANAGEMENT: Concurrent use of citalopram with agents known to prolong the QT interval should be avoided. Due to the risk of QT prolongation, citalopram doses greater than 40 mg once daily are not recommended. Citalopram doses should be limited to 20 mg once daily in patients who are CYP2C19 poor metabolizers or patients receiving CYP2C19 inhibitors. If patients have a persistent QTc measurement > 500 ms, discontinue citalopram. If a patient develops symptoms including dizziness, palpitations, or syncope, further evaluation is warranted included cardiac monitoring. The manufacturer recommends ECG monitoring in patients for whom citalopram is not recommended, including those receiving concurrent therapy with agents known to prolong the QT interval. Citalopram should be discontinued in patients with persistent QTc measurements greater than 500 ms.(1-2) Consider obtaining serum calcium, magnesium, and potassium levels at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Citalopram has been associated with dose-depended increases in the QTc interval. In healthy subjects, the maximum mean difference in QTc interval seen with 20 mg of citalopram and 60 mg of citalopram were 8.5 msec (90% CI = 6.2-10.8 msec) and 18.5 msec (90% CI = 16.0-21.0 msec), respectively. Based on extrapolation, a 40 mg dose of citalopram is expected to produce a mean increase in the QTc interval of 12.6 msec (90% CI = 10.9-14.3 msec).(1) In a clinical trial of use of citalopram for agitation in Alzheimer's disease, citalopram (30 mg daily) was associated with a mean increase in QTc of 18.1 msec.(5) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(6)	CELEXA, CITALOPRAM HBR
Crizotinib/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The use of crizotinib in patients maintained on agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: Consider periodic electrocardiogram (ECG) and electrolyte monitoring (calcium, magnesium, and potassium levels at baseline and regular intervals) in patients receiving concurrent therapy with crizotinib and another agent that prolongs the QTc interval.(1) In patients who develop a QTc greater than 500 ms on at least 2 separate ECGs, withhold crizotinib until recovery to baseline or to a QTc less than 481 ms, then resume crizotinib at reduced dose.(1) In patients who develop a QTc greater than 500 ms or greater than or equal to 60 ms change from baseline with Torsade de pointes or polymorphic ventricular tachycardia or signs/symptoms of serious arrhythmia, permanently discontinue crizotinib.(1) Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Crizotinib is associated with concentration-dependent QTc interval prolongation. In a clinical trial 2.1% of patients were found to have a QTcF greater than or equal to 500 msec and 5% of patients had an increase in QTcF by greater than or equal to 60 msec.(1) A retrospective review of 618 cancer patients treated with 902 administrations of tyrosine kinase inhibitors were evaluated for rate and incidence of QTc prolongation. In patients who received crizotinib, QTc prolongation was identified in 1 (50%) with 1 (100%) having Grade 1 (QTc 450-480 ms). No patients had a QTc change greater than or equal to 60 ms, ventricular tachycardia, sudden cardiac death, or TdP.(3) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(4)	XALKORI
Quetiapine/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The use of quetiapine in patients maintained on agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(3) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(3) PATIENT MANAGEMENT: The US manufacturer of quetiapine states that concurrent use with agents known to prolong the QT interval should be avoided.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Although quetiapine was not associated with QT or QTc changes in clinical trials, QT prolongation has been reported in post-marketing reports in conjunction with the use of other agents known to prolong the QT interval.(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(2)	QUETIAPINE FUMARATE, QUETIAPINE FUMARATE ER, SEROQUEL, SEROQUEL XR
Ondansetron/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1-3) CLINICAL EFFECTS: The use of ondansetron in patients maintained on agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1-3) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or in the elderly (> or = 75 years of age).(4) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(4) PATIENT MANAGEMENT: The risk for QT prolongation due to ondansetron is dose and route related. Intravenous (IV) doses lead to higher peak concentrations and systemic exposure and so have a greater risk for QT prolongation compared with the same dose given orally. Faster rates of IV infusion are also associated with a greater risk for QT prolongation.(5) If concomitant therapy is needed, correct electrolyte abnormalities prior to starting therapy. Monitor closely, particularly in patients with predisposing risk factors for QT prolongation (e.g. cardiac disease, female, elderly). Electrocardiogram (ECG) monitoring should be performed in patients receiving concurrent therapy.(1-3) The Canadian manufacturer of Zofran injection has specific recommendations for use of IV ondansetron in oncology patients greater than or equal to 75 years of age (5): - all IV doses must be diluted in 50 - 100 mL of compatible fluid and infused over at least 15 minutes - initial and repeat IV doses must not exceed 8 mg. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: In a double-blind, randomized, placebo and positive controlled cross-over study, an ondansetron intravenous (IV) dose of 32 mg increased the maximum mean QTcF by 19.6 msec (upper limit of 90% CI: 21.5). A dose of 8mg increased the QTcF by a maximum mean of 5.8 (upper limit of 90% CI: 7.8). A dose of 16 mg was predicted to have a mean increase in QTcF of 9.1 msec (upper limit of 90% CI: 11.2).(1) QT prolongation and torsades de pointes have been reported in post-marketing reports in patients receiving ondansetron.(2-3) In a review of published reports of QT prolongation associated with ondansetron administration, 67% of patients were also receiving another medication known to prolong the QT interval.(6) In a prospective, observational study, administration of a single ondansetron IV dose of 4 mg in the emergency department increased the mean and median QTc interval by 16.2 msec (95% CI 4.2-28.2 msec; p=0.01) and 12 msec (IQR 5.5-18 msec; p<0.01), respectively. Three patients had extreme QTc prolongation. With exclusion of those 3 patients, the median QTc prolongation was 10 msec (IQR 5-15 msec; p<0.01).(7) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(8)	ONDANSETRON HCL, ONDANSETRON HCL-0.9% NACL
Clozapine/QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Concurrent use of clozapine with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The use of clozapine in patients maintained on agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: Approach the concurrent use of clozapine and other agents that are known to prolong the QTc interval with caution.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Treatment with clozapine has been associated with QT prolongation as well as ventricular arrythmia, Torsades de Pointes, cardiac arrest, and sudden death.(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(3)	CLOZAPINE, CLOZAPINE ODT, CLOZARIL, VERSACLOZ
Voriconazole/QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Concurrent use of voriconazole with agents known to prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: Concurrent use may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes. PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: The manufacturer of voriconazole states concurrent use with agents known to prolong the QT interval should be administered with caution.(1) In patients maintained on voriconazole and other agents known to prolong the QT interval, consider a baseline ECG prior to administration to assess the risk/benefit of therapy. Consider obtaining serum calcium, magnesium, and potassium levels at baseline and at regular intervals. Correct any electrolyte abnormalities prior to initiation of therapy. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: A placebo-controlled, randomized, crossover study to evaluate the effect on the QT interval of healthy male and female subjects was conducted with three single oral doses of voriconazole and ketoconazole. The placebo-adjusted mean maximum increases in QTc from baseline after 800 mg, 1200 mg, and 1600 mg of voriconazole and after ketoconazole 800 mg were all <10 msec. No subject experienced an interval exceeding the potentially clinically relevant threshold of 500 msec.(1) In a retrospective study of 2,735 patients with a prolonged QTc interval, voriconazole use was associated with an increased risk of torsades de pointes.(4)	VFEND, VFEND IV, VORICONAZOLE
Fingolimod/QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Fingolimod is a sphingosine 1-phosphate (S1P) receptor modulator. Initiation of fingolimod has a negative chronotropic effect leading to a mean decrease in heart rate of 13 beats per minute (bpm) after the first dose. The first dose has also been associated with heart block.(1-3) Fingolimod blocks the capacity of lymphocytes to egress from lymph nodes, reducing the number of lymphocytes in peripheral blood. The mechanism by which fingolimod exerts therapeutic effects in multiple sclerosis is unknown but may involve the reduction of lymphocyte migration into the central nervous system.(1-3) CLINICAL EFFECTS: The heart rate lowering effect of fingolimod is biphasic with an initial decrease usually within 6 hours, followed by a second decrease 12 to 24 hours after the first dose. Symptomatic bradycardia and heart block, including third degree block, have been observed. Bradycardia may be associated with an increase in the QTc interval, increasing the risk for torsades de pointes. There is no consistent signal of increased incidence of QTc outliers, either absolute or change from baseline, associated with fingolimod treatment.(1-3) PREDISPOSING FACTORS: Pre-existing cardiovascular or cerebrovascular disease (e.g. heart failure, ischemic heart disease, history of myocardial infarction, stroke, or heart block), severe untreated sleep apnea, a prolonged QTc interval prior to fingolimod initiation, factors associated with QTc prolongation (e.g. hypokalemia, hypomagnesemia), or concomitant treatment with QT prolonging agents may increase risk for cardiovascular toxicity due to fingolimod. The risk of QT prolongation or torsades de pointes may also be increased in patients with a history of torsades de pointes, hypocalcemia, bradycardia, female gender, or advanced age.(4) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of the QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(4) PATIENT MANAGEMENT: Patients with a baseline QTc interval greater than or equal to 500 milliseconds should not be started on fingolimod. Patients with pre-existing cardiovascular or cerebrovascular disease (e.g. heart failure, ischemic heart disease, history of myocardial infarction, stroke, or heart block), severe untreated sleep apnea, or a prolonged QTc interval prior to fingolimod initiation should receive cardiologist consultation to evaluate the risks of fingolimod therapy. In all patients, first dose monitoring is recommended to monitor for bradycardia for the first 6 hours. Check blood pressure and pulse hourly. ECG monitoring is recommended prior to dosing and at the end of the observation period. US monitoring recommendations include additional monitoring for the following patients:(1) If heart rate (HR) is less than 45 beats per minute (bpm), the heart rate 6 hours postdose is at the lowest value postdose, or if the ECG shows new onset of second degree or higher AV block at the end of the monitoring period, then monitoring should continue until the finding has resolved. Continuous overnight ECG monitoring is recommended in patients requiring pharmacologic intervention for symptomatic bradycardia, some preexisting heart and cerebrovascular conditions, prolonged QTc before dosing or during 6 hours observation, concurrent therapy with QT prolonging drugs, or concurrent therapy with drugs that slow heart rate or AV conduction. Consult the prescribing information for full monitoring recommendations. United Kingdom recommendations:(3) Obtain a 12-lead ECG prior to initiating fingolimod therapy. Consult a cardiologist for pretreatment risk-benefit assessment if patient has a resting heart rate less than 55 bpm, history of syncope, second degree or greater AV block, sick-sinus syndrome, concurrent therapy with beta-blockers, Class Ia, or Class III antiarrhythmics, heart failure or other significant cardiovascular disease. Perform continuous ECG monitoring, measure blood pressure and heart rate every hour, and perform a 12-lead ECG 6 hours after the first dose. Monitoring should be extended beyond 6 hours if symptomatic bradycardia or new onset of second degree AV block, Mobitz Type II or third degree AV block has occurred at any time during the monitoring period. If heart rate 6 hours after the first dose is less than 40 bpm, has decreased more than 20 bpm compared with baseline, or if a new onset second degree AV block, Mobitz Type I (Wenckebach) persists, then monitoring should also be continued. If fingolimod treatment is discontinued for more than two weeks, the effects on heart rate and conduction could recur. Thus, first dose monitoring precautions should be followed upon reintroduction of fingolimod. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: After the first dose of fingolimod, heart rate decrease may begin within an hour. Decline is usually maximal at approximately 6 hours followed by a second decrease 12 to 24 hours after the first dose. The second dose may further decrease heart rate, but the magnitude of change is smaller than the first dose. With continued, chronic dosing, heart rate gradually returns to baseline in about one month.(1,2) In a thorough QT interval study of doses of 1.25 or 2.5 mg fingolimod at steady-state, when a negative chronotropic effect of fingolimod was still present, fingolimod treatment resulted in a prolongation of QTc, with the upper boundary of the 90% confidence interval (CI) of 14.0 msec. The cause of death in a patient who died within 24 hour after taking the first dose of fingolimod was not conclusive; however a link to fingolimod or a drug interaction with fingolimod could not be ruled out.(1)	FINGOLIMOD, GILENYA, TASCENSO ODT
Alfuzosin/QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Concurrent use of alfuzosin with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The use of alfuzosin in patients maintained on agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(3) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(3) PATIENT MANAGEMENT: Approach the concurrent use of alfuzosin and other agents that are known to prolong the QTc interval with caution.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(2)	ALFUZOSIN HCL ER, UROXATRAL
Sorafenib/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Concurrent use of sorafenib with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The use of sorafenib in patients maintained on agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: Patients receiving concurrent therapy with agents known to prolong the QTc interval should be monitored with electrocardiograms during treatment with sorafenib. Electrolytes (calcium, magnesium, and potassium) should also be monitored.(1) Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: In a non-randomized trial in 53 patients, sorafenib resulted in a mean change in QTc of 8.5 msec (upper bound of 90% CI: 13.3 msec).(1) A retrospective review of 618 cancer patients treated with 902 administrations of tyrosine kinase inhibitors were evaluated for rate and incidence of QTc prolongation. In patients who received sorafenib, QTc prolongation was identified in 13 (31.7%) with 5 (38.5%) having Grade 1 (QTc 450-480 ms) and 4 (30.7%) having Grade 2 (QTc 480-500 ms). Grade 3 events occurred in 2 (15.4%) having QTc greater than or equal to 500 ms and 2 (15.4%) having QTc change greater than or equal to 60 ms. No patients developed ventricular tachycardia, sudden cardiac death, or TdP.(3) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(4)	NEXAVAR, SORAFENIB
Pasireotide/QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Concurrent use of pasireotide with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The use of pasireotide patients maintained on agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(3) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(3) PATIENT MANAGEMENT: Pasireotide should be used with caution in patients receiving therapy with agents that prolong the QT interval. If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals.(1) Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: In randomized, blinded, crossover study in healthy subjects, pasireotide (0.6 mg BID) increased the placebo-subtracted QTcI by 12.7 msec (95 upper CI: 14.7 msec). Supra-therapeutic doses of 1.95 mg BID increased the placebo-subtracted QTcI by 16.6 msec (95 upper CI: 18.6 msec).(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(2)	SIGNIFOR, SIGNIFOR LAR
Bedaquiline/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Concurrent use of bedaquiline with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The use of bedaquiline patients maintained on agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: Bedaquiline should be used with caution in patients receiving therapy with agents that prolong the QT interval. Patients should receive a baseline electrocardiogram (ECG) before initiation, 2 weeks after initiation, during treatment as clinically indicated, and at the expected time of maximum increase of the QT interval when receiving concurrent agents that prolong the QT interval. Bedaquiline and other QT prolonging agents should be discontinued if the patient develops a clinically significant ventricular arrhythmia or a QTcF of greater than 500 msec confirmed by repeat ECGs. If a patient develops syncope, perform an ECG.(1) Also consider obtaining serum calcium, magnesium, and potassium levels at baseline and regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: In a clinical trial, mean increases in QTc were greater in patients treated with bedaquiline than with placebo. At Week 1, bedaquiline increased QTc by an average of 9.9 msec, compared with 2.5 msec for placebo. At Week 24, bedaquiline increased QTc by an average of 15.7 msec, compared with 6.2 msec for placebo. In another clinical trial in which patients received bedaquiline with other QT prolonging agents, QT prolongation was additive and proportional to the number of QT prolonging drugs used. Patients receiving bedaquiline alone averaged a QTc increase of 23.7 msec over baseline, while patients receiving bedaquiline with at least one other QT prolonging agent averaged a QTc increase of 30.7 msec.(1) In a study, bedaquiline was coadministered with QTc prolonging agents clofazimine and levofloxacin. In the study, 5% of patients had a QTc >= 500 ms and 43% of patients had an increase in QTc >= 60 ms from baseline.(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(3)	SIRTURO
Escitalopram/QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Concurrent use of multiple agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of multiple agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(1) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, and/or renal/hepatic dysfunction).(1) PATIENT MANAGEMENT: While the US FDA and manufacturer recommend no special precautions when escitalopram is used with QT prolonging agents,(2,3) Health Canada and the Canadian manufacturer of escitalopram discourage the concurrent use of agents known to prolong the QT interval(4,5) and the UK manufacturer states that concurrent use is contraindicated.(6) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(7) One or more of the drug pairs linked to this monograph have been included in a list of interactions that should be considered "high-priority" for inclusion and should not be inactivated in EHR systems. This DDI subset was vetted by an expert panel commissioned by the U.S. Office of the National Coordinator (ONC) for Health Information Technology.	ESCITALOPRAM OXALATE, LEXAPRO
Trazodone (Greater Than or Equal To 100 mg)/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Concurrent use of trazodone with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1,2) CLINICAL EFFECTS: The use of trazodone in patients maintained on agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1,2) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: The US manufacturer of trazodone states that concurrent use with agents known to prolong the QT interval should be avoided.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Trazodone has been reported to prolong the QT interval.(1) A thorough QT study in 20 subjects evaluated the effects of trazodone at doses of 20 mg, 60 mg and 140 mg. There was no evidence of QTc prolongation at the lowest trazodone dose of 20mg (mean effect on QTc of 4.5 ms 95% CI 3.7-5.3 ms), but at 60 mg and 140 mg, there was a significant effect that exceeds the E14 FDA Guidelines threshold of prolonging the QT/QTc interval by more than 5 ms. The study found a dose-dependent effect on QTc prolongation starting at 60 mg with a mean effect on QTc of 12.3 ms (95% CI 11-13.6 ms) and increasing with a 140 mg dose to a mean effect on QTc of 19.8 ms (95% CI 17.6-22.1).(3) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(4)	RALDESY, TRAZODONE HCL
Sevoflurane/QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Concurrent use of multiple agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of multiple agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(1) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, and/or renal/hepatic dysfunction).(1) PATIENT MANAGEMENT: Sevoflurane should be used with caution in patients taking agents known to prolong the QT interval.(2) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(3) One or more of the drug pairs linked to this monograph have been included in a list of interactions that should be considered "high-priority" for inclusion and should not be inactivated in EHR systems. This DDI subset was vetted by an expert panel commissioned by the U.S. Office of the National Coordinator (ONC) for Health Information Technology.	SEVOFLURANE, ULTANE
Ceritinib/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The use of ceritinib in patients maintained on agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) Patients with severe hepatic impairment (Child-Pugh C) may be at increased risk of this interaction. Ceritinib dose reduction may be warranted in severe hepatic impairment. See prescribing information for recommendations.(1) PATIENT MANAGEMENT: When possible, avoid coadministration of ceritinib with other QT prolonging agents. Consider obtaining electrocardiogram (ECG) and serum calcium, magnesium, and potassium levels at baseline and regular intervals in patients receiving concurrent therapy with ceritinib and another agent that may prolong the QTc interval.(1) In patients who develop a QTc interval greater than 500 msec on at least 2 occasions, withhold ceritinib until the QTc interval is less than 481 msec or recovery to baseline if baseline QTc was greater than or equal to 481 msec, then resume ceritinib with a 150 mg dose reduction. If the patient develops QTc interval prolongation in combination with torsades de pointes or polymorphic ventricular tachycardia or signs/symptoms of serious arrhythmia, permanently discontinue ceritinib.(1) Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: In a clinical trial 3% of patients experienced a QTc interval increase over baseline greater than 60 msec. Less than 1% of patients (1 of 304) treated with ceritinib was found to have a QTc greater than 500 msec. The upper limit of the 90% confidence interval for mean QTC increase was 16 msec at ceritinib 750 mg. Data suggested that ceritinib produces concentration-dependent QTc interval prolongation.(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(3)	ZYKADIA
Clarithromycin/QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Clarithromycin may prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1-15) CLINICAL EFFECTS: The concurrent use of clarithromycin with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1-15) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(1) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, and/or renal/hepatic dysfunction).(1) PATIENT MANAGEMENT: General monitoring when concurrent therapy is warranted: consider obtaining serum calcium, magnesium, and potassium levels at baseline and regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. Agent specific recommendations: The manufacturers of apomorphine,(2) clarithromycin,(3) gatifloxacin,(4) gemifloxacin,(5) norfloxacin,(6) and sevoflurane(7) state that these agents should used with caution with other agents known to prolong the QT interval. While the US FDA and manufacturer recommend no special precautions when escitalopram is used with QT prolonging agents,(8,9) Health Canada and the Canadian manufacturer of escitalopram discourage the concurrent use of agents known to prolong the QT interval(10,11) and the UK manufacturer states that concurrent use is contraindicated.(12) The US manufacturer of ciprofloxacin states that ciprofloxacin should be used with caution with other agents known to prolong the QT interval, especially in the elderly.(13) The UK manufacturer of ciprofloxacin states that ciprofloxacin should be used with caution in patients at risk for torsades.(14) DISCUSSION: Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(15) One or more of the drug pairs linked to this monograph have been included in a list of interactions that should be considered "high-priority" for inclusion and should not be inactivated in EHR systems. This DDI subset was vetted by an expert panel commissioned by the U.S. Office of the National Coordinator (ONC) for Health Information Technology.	CLARITHROMYCIN, CLARITHROMYCIN ER, LANSOPRAZOL-AMOXICIL-CLARITHRO, OMECLAMOX-PAK
Lenvatinib/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: Concurrent use of lenvatinib in patients taking other medications that prolong the QT interval may result in additive QT prolongation. QT prolongation may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, hypoalbuminemia, bradycardia, female gender, or advanced age.(1,2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: Monitor electrocardiograms during concurrent therapy with lenvatinib and agents that prolong the QT interval. In a clinical trial of patients with refractory, progressive thyroid cancer, QT prolongation was reported in 9% of lenvatinib patients. Monitor and correct electrolyte abnormalities in all patients.(1) This is particularly important in lenvatinib patients as diarrhea, nausea, vomiting, and decreased appetite are common side effects which may increase the risk for electrolyte disturbances. Monitor ECG at baseline and at regular intervals. Lenvatinib dose must be withheld if the QTc exceeds 500 msec until QTc resolves to less than 480 msec or baseline. Lenvatinib must be resumed at reduced dose when QTc prolongation resolves to less than 480 msec or to baseline. Dose adjustments below are indication specific and are for patients with normal hepatic and renal function:(1) Dose Modifications in Differentiated Thyroid Cancer(DTC): - First occurrence of QTc > 500 msec or onset of another Grade 2 or Grade 3 Adverse Reaction or Grade 4 Laboratory Abnormality: Interrupt therapy until resolved to Grade 0-1 or baseline then decrease dose to 20 mg once daily - Second occurrence of QTc > 500 msec or onset of another Grade 2 or Grade 3 Adverse Reaction or Grade 4 Laboratory Abnormality: Interrupt therapy until resolved to Grade 0-1 or baseline then decrease dose to 14 mg once daily - Third occurrence of QTc > 500 msec or onset of another Grade 2 or Grade 3 Adverse Reaction or Grade 4 Laboratory Abnormality: Interrupt therapy until resolved to Grade 0-1 or baseline then decrease dose 10 mg once daily Dose Modifications in Renal Cell Cancer (RCC): - First occurrence of QTc > 500 msec or onset of another Grade 2 or Grade 3 Adverse Reaction or Grade 4 Laboratory Abnormality: Interrupt therapy until resolved to Grade 0-1 or baseline then decrease dose to 14 mg once daily - Second occurrence of QTc > 500 msec or onset of another Grade 2 or Grade 3 Adverse Reaction or Grade 4 Laboratory Abnormality: Interrupt therapy until resolved to Grade 0-1 or baseline then decrease dose to 10 mg once daily - Third occurrence of QTc > 500 msec or onset of another Grade 2 or Grade 3 Adverse Reaction or Grade 4 Laboratory Abnormality: Interrupt therapy until resolved to Grade 0-1 or baseline then decrease dose 8 mg once daily Dose Modifications in Hepatocellular Carcinoma (HCC) for Actual weight 60 kg or greater: - First occurrence of QTc > 500 msec or onset of another Grade 2 or Grade 3 Adverse Reaction or Grade 4 Laboratory Abnormality: Interrupt therapy until resolved to Grade 0-1 or baseline then decrease dose to 8 mg once daily - Second occurrence of QTc > 500 msec or onset of another Grade 2 or Grade 3 Adverse Reaction or Grade 4 Laboratory Abnormality: Interrupt therapy until resolved to Grade 0-1 or baseline then decrease dose to 4 mg once daily - Third occurrence of QTc > 500 msec or onset of another Grade 2 or Grade 3 Adverse Reaction or Grade 4 Laboratory Abnormality: Interrupt therapy until resolved to Grade 0-1 or baseline then decrease dose 4 mg every other day Dose Modifications in Hepatocellular Carcinoma (HCC) for Actual weight less than 60 kg: - First occurrence of QTc > 500 msec or onset of another Grade 2 or Grade 3 Adverse Reaction or Grade 4 Laboratory Abnormality: Interrupt therapy until resolved to Grade 0-1 or baseline then decrease dose to 4 mg once daily - Second occurrence of QTc > 500 msec or onset of another Grade 2 or Grade 3 Adverse Reaction or Grade 4 Laboratory Abnormality: Interrupt therapy until resolved to Grade 0-1 or baseline then decrease dose to 4 mg every other day - Third occurrence of QTc > 500 msec or onset of another Grade 2 or Grade 3 Adverse Reaction or Grade 4 Laboratory Abnormality: Interrupt therapy until resolved to Grade 0-1 or baseline and discontinue lenvatinib (1) Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: In a clinical trial of patients with refractory, progressive thyroid cancer, QT prolongation was reported in 9% of lenvatinib patients and 2% of placebo patients. The incidence of Grade 3 QT prolongation of > 500 msec was reported in 2% of lenvatinib patients compared with no reports in placebo patients.(1) In contrast, a single lenvatinib dose of 32 mg (1.3 times the recommended daily dose) did not prolong the QT/QTc interval in a thorough QT study performed in healthy subjects.(1) A retrospective review of 618 cancer patients treated with 902 administrations of tyrosine kinase inhibitors were evaluated for rate and incidence of QTc prolongation. In patients who received lenvatinib, QTc prolongation was identified in 9 (42.9%) with 4 (44.4%) having Grade 1 (QTc 450-480 ms) and 3 (33.3%) having Grade 2 (QTc 480-500 ms). Grade 3 events occurred in 0 (0%) having QTc greater than or equal to 500 ms and 1 (11.1%) having QTc change greater than or equal to 60 ms. Ventricular tachycardia was seen in 1 (11.1%) patient.(3)	LENVIMA
Flecainide/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Flecainide has been shown to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of flecainide with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes(TdP).(1) PREDISPOSING FACTORS: In general, the risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(1) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(1) PATIENT MANAGEMENT: If possible, avoid the use of flecainide with other agents known to prolong the QT interval. If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(2)	FLECAINIDE ACETATE
Azithromycin/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Azithromycin has been shown to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of azithromycin with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes(TdP).(1) PREDISPOSING FACTORS: In general, the risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(1) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(1) PATIENT MANAGEMENT: If possible, avoid the use of azithromycin with other agents known to prolong the QT interval. If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(2)	AZITHROMYCIN, ZITHROMAX, ZITHROMAX TRI-PAK
Chloroquine/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Chloroquine has been shown to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of chloroquine with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes(TdP).(1) PREDISPOSING FACTORS: In general, the risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(1) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(1) PATIENT MANAGEMENT: If possible, avoid the use of chloroquine with other agents known to prolong the QT interval. If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(2)	CHLOROQUINE PHOSPHATE
Chlorpromazine/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Chlorpromazine has been shown to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of chlorpromazine with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes(TdP).(1) PREDISPOSING FACTORS: In general, the risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(1) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(1) PATIENT MANAGEMENT: If possible, avoid the use of chlorpromazine with other agents known to prolong the QT interval. If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(2)	CHLORPROMAZINE HCL
Cilostazol/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Cilostazol has been shown to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of cilostazol with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes(TdP).(1) PREDISPOSING FACTORS: In general, the risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(1) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(1) PATIENT MANAGEMENT: If possible, avoid the use of cilostazol with other agents known to prolong the QT interval. If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(2)	CILOSTAZOL
Donepezil/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Donepezil has been shown to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of donepezil with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes(TdP).(1) PREDISPOSING FACTORS: In general, the risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(1) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(1) PATIENT MANAGEMENT: If possible, avoid the use of donepezil with other agents known to prolong the QT interval. If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: A pharmacovigilance study based on the FDA Adverse Event Reporting System (FAERS) database found that, of a total of 33,626 cases of TdP/QT prolongation reported between January 2004 and September 2022, 430 cases occurred in patients on donepezil. The disproportionality analysis found a ROR = 8.98, 95% CI (8.16, 9.89) and a PRR = 8.88, chi-square = 2944.95.(2) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(3)	ADLARITY, ARICEPT, DONEPEZIL HCL, DONEPEZIL HCL ODT, MEMANTINE HCL-DONEPEZIL HCL ER, NAMZARIC
Erythromycin/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Erythromycin has been shown to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of erythromycin with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes(TdP).(1) PREDISPOSING FACTORS: In general, the risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(1) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(1) PATIENT MANAGEMENT: If possible, avoid the use of erythromycin with other agents known to prolong the QT interval. If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(2)	E.E.S. 200, E.E.S. 400, ERY-TAB, ERYPED 200, ERYPED 400, ERYTHROCIN LACTOBIONATE, ERYTHROCIN STEARATE, ERYTHROMYCIN, ERYTHROMYCIN ESTOLATE, ERYTHROMYCIN ETHYLSUCCINATE, ERYTHROMYCIN LACTOBIONATE
Fluconazole/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Fluconazole has been shown to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of fluconazole with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes(TdP).(1) PREDISPOSING FACTORS: In general, the risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(1) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(1) PATIENT MANAGEMENT: If possible, avoid the use of fluconazole with other agents known to prolong the QT interval. If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(2)	DIFLUCAN, FLUCONAZOLE, FLUCONAZOLE-NACL
Pentamidine/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Pentamidine has been shown to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of pentamidine with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes(TdP).(1) PREDISPOSING FACTORS: In general, the risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(1) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(1) PATIENT MANAGEMENT: If possible, avoid the use of pentamidine with other agents known to prolong the QT interval. If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(2)	PENTAM 300, PENTAMIDINE ISETHIONATE
Propofol/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Propofol has been shown to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of propofol with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes(TdP).(1) PREDISPOSING FACTORS: In general, the risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(1) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(1) PATIENT MANAGEMENT: If possible, avoid the use of propofol with other agents known to prolong the QT interval. If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(2)	DIPRIVAN, PROPOFOL
Osimertinib/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Osimertinib prolongs the QTc interval.(1) Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(2,3) CLINICAL EFFECTS: The concurrent use of osimertinib with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(2,3) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(3) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(3) PATIENT MANAGEMENT: Osimertinib prolongs the QT interval. Premarket clinical trials excluded patients with a baseline QTc > or = 470 msec. In these trials 11 patients (2.7%) had increase in QTc greater than 60 msec.(1) Manufacturer recommendations: when feasible, avoid concurrent administrations of osimertinib with drugs known to prolong the QTc interval. Conduct baseline and periodic monitoring with ECGs in patients with congenital long QTc syndrome, congestive heart failure, electrolyte abnormalities (e.g. serum calcium, magnesium, and potassium), or those taking medications known to prolong the QT interval.(1) Dose adjustments (1): - If QTc is greater than 500 msec on at least 2 separate ECGs, withhold osimertinib until QTc is < 481 msec or recovery to baseline (if baseline QTc was greater than or equal to 481 msec), then resume osimertinib at 40 mg per day. - For QTc prolongation with signs or symptoms of life threatening arrhythmia, permanently discontinue osimertinib. During concomitant therapy with another QT prolonging agent, monitor patients closely for prolongation of the QT interval.(1) Obtain serum calcium, magnesium, and potassium levels and monitoring ECG at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: A retrospective review of 618 cancer patients treated with 902 administrations of tyrosine kinase inhibitors were evaluated for rate and incidence of QTc prolongation. In patients who received osimertinib, QTc prolongation was identified in 4 (25%) with 1 (25%) having Grade 1 (QTc 450-480 ms) and 1 (25%) having Grade 2 (QTc 480-500 ms). Grade 3 events occurred in 1 (25%) having QTc greater than or equal to 500 ms and 1 (25%) having QTc change greater than or equal to 60 ms. No patients had ventricular tachycardia, sudden cardiac death, or TdP.(4) In clinical studies of 1813 patients treated with osimertinib monotherapy, 1.1% of patients were found to have a QTc interval greater than 500 ms and 4.3% of patients had an increase from baseline QTc > 60 ms.(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(2)	TAGRISSO
Pimavanserin/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Pimavanserin prolongs the QTc interval.(1) Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(2,3) CLINICAL EFFECTS: The concurrent use of pimavanserin with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(2,3) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(3) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(3) PATIENT MANAGEMENT: Avoid the use of pimavanserin in patients receiving QT prolonging agents.(1) During concomitant therapy with another QT prolonging agent, monitor patients closely for prolongation of the QT interval.(1) Obtain serum calcium, magnesium, and potassium levels and monitoring ECG at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: In thorough-QT study, pimavanserin (at twice the therapeutic dose) found that the maximum mean change was 13.5 (16.6) msec. In placebo-controlled effectiveness studies, mean increases of 5-8 msec were observed with normal dosages of 37 mg daily. Sporadic QTcF values of equal to or greater than 500 msec and change from baseline values equal to or greater than 60 msec were observed at this dose as well.(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(2)	NUPLAZID
Hydroxyzine/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Concurrent use of hydroxyzine with agents that prolong the QTc interval may result in additive effects on the QTc interval.(1-4) CLINICAL EFFECTS: The concurrent use of hydroxyzine with agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1-4) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(5) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, and/or renal/hepatic dysfunction).(5) Doses of hydroxyzine greater than 100 mg/day may also increase the risk.(1,2) PATIENT MANAGEMENT: Concurrent use of hydroxyzine with agents known to prolong the QT interval is contraindicated in Canada(1,2) and the UK.(3) The US manufacturer states that concurrent use should be approached with caution.(4) If concurrent therapy is deemed medically necessary, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: In vitro data indicates that hydroxyzine blocks the hERG channel, which results in the potential risk of QT interval prolongation.(6) In a placebo controlled, non-thorough QT study, 10 patients in the placebo group (n=152) had a change in QT interval from baseline between 30 ms and 60 ms and one patient presented a change from baseline higher than 60 ms. In the hydroxyzine group (n=148), 14 subjects had a change in QT interval from baseline between 30 and 60 ms and were considered to have a potential risk factor for risk of QT interval prolongation and TdP due to relevant medical history, concomitant medication potentially associated with the induction of prolongation of QT interval, and/or polymedication.(6) Health Canada reviewed 61 cases of QT interval prolongation or torsades de pointes with hydroxyzine. In a majority of cases, patients had additional risk factors for QT prolongation. Three reports provided enough data for a more detailed review. Hydroxyzine was found to be either "possible" or "probably" contribution to QT prolongation/torsades in these reports.(1) The European Medicines Agency's Pharmacovigilance Risk Assessment Committee (PRAC) reviewed 190 case reports found in a search of "torsade de pointes/QT prolongation with hydroxyzine". Forty-two non-fatality cases were subdivided into torsades (n=16), QT prolongation (n=21), and ventricular tachycardia (n=5). All included risk factors for QT interval prolongation and TdP (cardiac disorders, hypokalemia, long QT syndrome, bradycardia, concomitant drugs which are known to prolong the QT interval). Dosages ranged from <= 100 mg/day (n=10), > 100 mg/day to <=300 mg/day (n=4), > 300 mg/day (n=8), overdosages (n=11), and premedication (n=9). Twenty-one cases involving fatalities had at least one risk factor for QT prolongation. The PRAC concluded that post-marketing cases of QT interval prolongation, TdP and ventricular tachycardia confirm the findings of the hERG studies suggesting that hydroxyzine blocks hERG channels. No difference in the risk of QT interval prolongation could be observed based on the indication, age of the subject, or dose.(6) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(7)	HYDROXYZINE HCL, HYDROXYZINE PAMOATE
Efavirenz/QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Efavirenz has been observed to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of efavirenz with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) CYP2B6 genotype may also increase the risk of this interaction. Patients who are most susceptible to this interaction are patients who are CYP2B6 poor metabolizers with CYP2B6 6/6 allele.(3) PATIENT MANAGEMENT: The US manufacturer of efavirenz states alternatives should be considered when concurrent administration with a drug with a known risk of Torsade de Pointes or when administered to patients at higher risk of Torsade de Pointes. Limited information is available on the potential pharmacodynamic interaction between efavirenz and drugs that prolong the QT interval; however, QT prolongation has been observed with efavirenz.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: A thorough QT study was conducted in the general population in 120 healthy subjects receiving efavirenz 600 mg daily. Time-matched differences in QTc with efavirenz compared to placebo was evaluated on day 11, at 6 hours post dose. The mean change in QTc was 5.2 msec and no change in QTc was greater than 10 msec.(4) In addition to the thorough QT study, the effect of efavirenz on the QTc interval was evaluated in 58 healthy subjects based on CYP2B6 genotype. CYP2B6 polymorphism was evaluated for each patient and results were the following: 65% with 1/1 or 1/4 allele (wild-type metabolizers), 26% with 1/6 allele (intermediate metabolizers) and 9% with 6/6 allele (slow metabolizers). Subjects with 2 copies of the CYP2B66 allele had significantly higher efavirenz exposure at steady-state (p<0.05). At steady-state concentrations of efavirenz, patients with CYP2B6 1/1 or 1/6 alleles had no change in the QTc interval (p>0.05). However, patients with CYP2B6 6/*6 allele had an increase in QTc mean +/- SD from 406 +/- 16.4 to 423 +/- 11.8 msec (p=0.02).(3) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(5)	EFAVIRENZ, EFAVIRENZ-EMTRIC-TENOFOV DISOP, EFAVIRENZ-LAMIVU-TENOFOV DISOP, SYMFI, SYMFI LO
Ribociclib/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Concurrent use of ribociclib with agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of ribociclib with agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: Avoid concurrent use of ribociclib with agents known to prolong the QT interval.(1) If concurrent therapy is deemed medically necessary, monitor patients closely. Obtain serum calcium, magnesium, and potassium levels and correct any electrolyte abnormalities at the beginning of each ribociclib cycle. Monitor ECG at baseline, Day 14 of the first cycle, at the beginning of the second cycle, and as necessary. If a prolonged QTc is noted, refer to ribociclib prescribing information for current dose modification and management instructions. Ribociclib may need to be interrupted, reduced, or discontinued.(1) Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Ribociclib has been shown to prolong the QTc interval in a concentration-dependent manner. At steady state, the mean increase in QTc interval exceeded 20 msec.(1) In MONALEESA-7, an increase of greater than 60 ms from baseline in the QTcF interval was observed in 14/87 (16%) of patients in the ribociclib and tamoxifen combination group.(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(3)	KISQALI
Inotuzumab Ozogamicin/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Concurrent use of inotuzumab ozogamicin with agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of inotuzumab ozogamicin with agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: When possible, discontinue QT prolonging agents prior to therapy with inotuzumab ozogamicin or use alternative agents during inotuzumab ozogamicin therapy.(1) When concurrent therapy cannot be avoided, obtain ECGs and electrolyte values (serum calcium, magnesium, and potassium) prior to the start of treatment, after initiation of any drug known to prolong the QT interval, and periodically monitor during therapy.(1) Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting.(1) DISCUSSION: Inotuzumab ozogamicin was shown to prolong the QT interval in clinical trials. In the INO-VATE trial, 3% (4/162) of patients experienced an increase in QTc equal to or greater than 60 msec. No patients has QTc values greater than 500 msec. Grade 2 QT prolongation was reported in 1% (2/164) patients. There were no reports of Grade 3 QT prolongation or Torsade de Pointes.(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(3)	BESPONSA
Lofexidine/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Lofexidine has been shown to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1,2) CLINICAL EFFECTS: Concurrent use of lofexidine and agents known to prolong the QT interval may exacerbate QT prolongation.(1,2) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, advanced age,(3) renal impairment, and/or hepatic impairment.(1,2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(3) PATIENT MANAGEMENT: The UK manufacturer of lofexidine states that concurrent use of lofexidine and QT prolonging agents should be avoided.(1) The US manufacturer states that ECGs should be monitored in patients receiving concurrent therapy with lofexidine and agents that are known to prolong the QT interval.(2) Consider obtaining serum calcium, magnesium, and potassium levels at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: In a study of healthy volunteers, lofexidine 1.44 mg to 1.8 mg had a change from baseline in QTc of 14.4 msec and 13.6 msec, respectively.(2) In a dose response study, lofexidine had a mean QTc prolongation of 7.3 msec and 9.3 msec at doses of 2.16 mg/day and 2.88 mg/day, respectively.(2) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(4)	LOFEXIDINE HCL, LUCEMYRA
Trazodone (Less Than 100 mg)/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Concurrent use of trazodone with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1,2) CLINICAL EFFECTS: The use of trazodone in patients maintained on agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1,2) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: The US manufacturer of trazodone states that concurrent use with agents known to prolong the QT interval should be avoided.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Trazodone has been reported to prolong the QT interval.(1) A thorough QT study in 20 subjects evaluated the effects of trazodone at doses of 20 mg, 60 mg and 140 mg. There was no evidence of QTc prolongation at the lowest trazodone dose of 20mg (mean effect on QTc of 4.5 ms 95% CI 3.7-5.3 ms), but at 60 mg and 140 mg, there was a significant effect that exceeds the E14 FDA Guidelines threshold of prolonging the QT/QTc interval by more than 5 ms. The study found a dose-dependent effect on QTc prolongation starting at 60 mg with a mean effect on QTc of 12.3 ms (95% CI 11-13.6 ms) and increasing with a 140 mg dose to a mean effect on QTc of 19.8 ms (95% CI 17.6-22.1).(3) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(4)	TRAZODONE HCL
Encorafenib/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Concurrent use of encorafenib with agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of encorafenib with agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: Avoid the concurrent use of encorafenib with medications that prolong the QT interval.(1) Recommended dosage modifications for encorafenib and QTc prolongation adverse reactions include: - QTcF greater than 500 ms and less than or equal to 60 ms increase from baseline: Withhold encorafenib until QTcF less than or equal to 500 ms. Resume at reduced dose. If more than one recurrence, permanently discontinue encorafenib. - QTcF greater than 500 ms and greater than 60 ms increase from baseline: Permanently discontinue encorafenib.(1) See prescribing information for additional information regarding dose reductions.(1) When concurrent therapy cannot be avoided, obtain ECGs and electrolyte values (serum calcium, magnesium, and potassium) prior to the start of treatment, after initiation of any drug known to prolong the QT interval, and periodically monitor during therapy. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Encorafenib has been associated with a dose-dependent QTc interval prolongation. Following administration of encorafenib in combination with binimetinib, the largest mean (90% CI) QTcF change from baseline was 18 ms (14-22 ms), based on central tendency analysis.(1) Following administration of encorafenib in combination with cetuximab and mFOLFOX6, an increase of QTcF >500 ms was measured in 3.6% (8/222) of patients.(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(3)	BRAFTOVI
Ivosidenib/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Concurrent use of ivosidenib with agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of ivosidenib with agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: Avoid the concurrent use of ivosidenib with medications that prolong the QT interval.(1) When concurrent therapy cannot be avoided, obtain ECGs and electrolyte values (serum calcium, magnesium, and potassium) prior to the start of treatment, after initiation of any drug known to prolong the QT interval, and periodically monitor during therapy. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. If QTc prolongation develops: ---Monitor and supplement electrolytes as clinically indicated ---Review and adjust concomitant QT prolonging medications ---Interrupt ivosidenib therapy ---Monitor ECGs at least weekly for 2 weeks following resolution of QTc prolongation ---Follow labeling recommendations regarding restarting ivosidenib.(1) DISCUSSION: In clinical trials of ivosidenib, 9% of patients experienced a QTc interval greater than 500 msec and 14% of patients had an increased from baseline QTc interval of greater than 60 msec. Patients with a baseline QTc of equal to or greater than 450 msec without pre-existing bundle branch block, or with a history of long QT syndrome were excluded from this trial.(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(3)	TIBSOVO
Glasdegib/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Concurrent use of glasdegib with agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of glasdegib with agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: Avoid the concurrent use of glasdegib with medications that prolong the QT interval.(1) When concurrent therapy cannot be avoided, obtain ECGs and electrolyte values (serum calcium, magnesium, and potassium) prior to the start of treatment, after initiation of any drug known to prolong the QT interval, and periodically monitor during therapy. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. If QTc prolongation develops: ---Monitor and supplement electrolytes as clinically indicated ---Review and adjust concomitant QT prolonging medications ---Interrupt glasdegib therapy for QTc interval greater than 500 ms. ---Monitor ECGs at least weekly for 2 weeks following resolution of QTc prolongation ---Follow labeling recommendations regarding restarting glasdegib.(1) DISCUSSION: In a randomized, single-dose, double-blind, 4-way cross-over, placebo- and open-label moxifloxacin-controlled study in 36 healthy subjects, the largest placebo and baseline-adjusted QTc interval change was 8 msec (90% CI: 6-10 msec) with a single 150 mg dose of glasdegib (The 150 mg single dose was used to achieve therapeutic plasma concentrations). With two-fold therapeutic plasma concentrations (achieved with a 300 mg single dose), the QTc change was 13 msec (90% CI: 11-16 msec).(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(3)	DAURISMO
Gilteritinib/QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Concurrent use of gilteritinib with agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of gilteritinib with agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(1) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, and/or renal/hepatic dysfunction).(1) PATIENT MANAGEMENT: When concurrent therapy cannot be avoided, obtain ECGs and electrolyte values (serum calcium, magnesium, and potassium) prior to the start of treatment, after initiation of any drug known to prolong the QT interval, and periodically monitor during therapy. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. Prior to initiation of therapy with gilteritinib, obtain baseline ECG and on days 8 and 15 of cycle 1, and prior to the start of the next two subsequent cycles. If QTc prolongation develops: ---Monitor and supplement electrolytes as clinically indicated ---Review and adjust concomitant QT prolonging medications For a QTc interval greater than 500 msec: ---Interrupt gilteritinib therapy ---Resume gilteritinib therapy at 80 mg when the QTc interval returns to within 30 msec of baseline or <= 480 msec. For QTc interval increased by > 30 msec on ECG on Day 8 of cycle 1: ---Confirm with ECG on Day 9 ---If confirmed, consider dose reduction to 80 mg.(2) DISCUSSION: In the gilteritinib clinical trial, 1.4% of patients developed a QTc interval greater than 500 msec and 7% of patients had an increase QTc greater than 60 msec.(2) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(3)	XOSPATA
Pitolisant/QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Concurrent use of pitolisant with agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of pitolisant with agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: Patients who are CYP2D6 poor metabolizers or on concurrent use with CYP2D6 inhibitors are at increased risk for higher systemic exposure to pitolisant and may be at increased risk of QT prolongation.(1) The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: When concurrent therapy cannot be avoided, obtain ECGs and electrolyte values (serum calcium, magnesium, and potassium) prior to the start of treatment, after initiation of any drug known to prolong the QT interval, and periodically monitor during therapy. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting.(2) DISCUSSION: In two dedicated QT prolongation studies, supra-therapeutic doses of pitolisant at 3-6 times the therapeutic dose (108-216 mg) were seen to cause mild to moderate QTc prolongation (10-13 ms). A study in patients who were CYP2D6 poor metabolizers had higher systemic exposure up to 3-fold compared to CYP2D6 extensive metabolizers.(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(3)	WAKIX
Entrectinib/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Concurrent use of entrectinib with agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of entrectinib with agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: Avoid the concurrent use of entrectinib with medications that prolong the QT interval.(1) When concurrent therapy cannot be avoided, obtain ECGs and electrolyte values (serum calcium, magnesium, and potassium) prior to the start of treatment, after initiation of any drug known to prolong the QT interval, and periodically monitor during therapy. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. If QTc prolongation develops: ---Monitor and supplement electrolytes as clinically indicated ---Review and adjust concomitant QT prolonging medications ---Interrupt entrectinib therapy for QTc interval greater than 500 ms. ---Follow labeling recommendations regarding restarting entrectinib.(1) If torsade de pointes, polymorphic ventricular tachycardia, and/or signs/symptoms of serious arrhythmia occur, permanently discontinue entrectinib.(1) DISCUSSION: In clinical trials, 3.1% of patients with at least one post-baseline ECG experienced QTcF prolongation of greater than 60 msec after starting entrectinib..(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(3)	ROZLYTREK
Lefamulin/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Concurrent use of lefamulin with agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of lefamulin with agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: Avoid the concurrent use of lefamulin with medications that prolong the QT interval.(1) When concurrent therapy cannot be avoided, obtain ECGs and electrolyte values (serum calcium, magnesium, and potassium) prior to the start of treatment, after initiation of any drug known to prolong the QT interval, and periodically monitor during therapy. Correct any electrolyte abnormalities.(1) Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: In a thorough QT study, intravenous lefamulin increased the QTcF 13.6 msec (90% CI = 15.5 msec) and oral lefamulin increased the QTcF by 9.3 msec (90% CI = 10.9 msec).(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(3)	XENLETA
Hydroxychloroquine/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Hydroxychloroquine has been observed to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of hydroxychloroquine with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: The US manufacturer of hydroxychloroquine states that hydroxychloroquine should not be administered with other agents that prolong the QT interval.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: The manufacturer states that hydroxychloroquine has been shown to prolong the QT interval;(1) however, conditions that hydroxychloroquine treats have also been associated with QT prolongation. Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(3)	HYDROXYCHLOROQUINE SULFATE, PLAQUENIL, SOVUNA
Amisulpride/QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Amisulpride has been shown to prolong the QT interval. Concurrent use with QT prolonging agents may result in additive effects on the QT interval.(1) CLINICAL EFFECTS: The concurrent use of amisulpride with agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: Use caution when using amisulpride concurrently with other agents that can prolong the QT interval. Amisulpride may cause a dose and concentration dependent increase in the QTc interval. When concurrent therapy cannot be avoided, obtain ECGs and electrolyte values (serum calcium, magnesium, and potassium) prior to the start of treatment, after initiation of any drug known to prolong the QT interval, and periodically monitor during therapy. ECG monitoring is recommended in patients with pre-existing arrhythmias or cardiac conduction disorders; electrolyte abnormalities; congestive heart failure; or in patients taking medications or with other medical conditions known to prolong the QT interval. Correct any electrolyte abnormalities.(1) Instruct patients to report any irregular heartbeat, dizziness, or fainting.(2) DISCUSSION: QT prolongation and torsades de pointes have been reported with amisulpride. In a study in 40 patients with post operative nausea and vomiting, amisulpride increased baseline QTcF by 5 msec after a 2-minute intravenous infusion of 5 mg and by 23.4 msec after an 8-minute intravenous infusion of 40 mg. Based on an exposure-response relationship, it is expected that a 10 mg intravenous infusion over 1 minute may increase the QTcF by 13.4 msec.(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(3)	BARHEMSYS
Osilodrostat/QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Osilodrostat has been shown to prolong the QT interval. Concurrent use with QT prolonging agents may result in additive effects on the QT interval.(1) CLINICAL EFFECTS: The concurrent use of osilodrostat with agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: Use caution when using osilodrostat concurrently with other agents that can prolong the QT interval and consider more frequent ECG monitoring. A dose-dependent QT interval prolongation was noted in clinical studies. Prior to initiating therapy with osilodrostat, obtain a baseline ECG and monitor for QTc interval changes thereafter. Consider temporary discontinuation of therapy if the QTc interval increases > 480 msec. When concurrent therapy cannot be avoided, obtain ECGs and electrolyte values (serum calcium, magnesium, and potassium) prior to the start of treatment, after initiation of any drug known to prolong the QT interval, and periodically monitor during therapy. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting.(2) DISCUSSION: QTc prolongation has been reported with osilodrostat. In a thorough QT study in 86 healthy patients, osilodrostat increased baseline QTcF by 1.73 msec at a 10 mg dose and 25.38 msec at a 150 mg dose (up to 2.5 times the maximum recommended dosage). The predicted mean placebo-corrected QTcF at the highest recommended dose in clinical practice (30 mg twice daily) was estimated as 5.3 msec.(1) In a clinical study, five patients (4%) were reported to have an event of QT prolongation, three patients (2%) had a QTcF increase of > 60 msec from baseline, and 18 patients (13%) had a new QTcF value of > 450 msec.(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(3)	ISTURISA
Oxaliplatin/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Concurrent use of oxaliplatin with agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of oxaliplatin with agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: Avoid the concurrent use of oxaliplatin in patients with congenital long QT syndrome. ECG monitoring is recommended if oxaliplatin therapy is initiated in patients with congestive heart failure, bradyarrhythmias, drugs known to prolong the QT interval, and electrolyte abnormalities.(1) When concurrent therapy cannot be avoided, obtain ECGs and electrolyte values (serum calcium, magnesium, and potassium) prior to the start of treatment, after initiation of any drug known to prolong the QT interval, and periodically monitor during therapy. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Prescribing information for oxaliplatin states post-marketing cases of QT prolongation and ventricular arrhythmias, including fatal Torsades de Pointes, have been reported.(1) Case reports have documented QT prolongation in patients with varying cancer indications for oxaliplatin.(3-6) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(7)	OXALIPLATIN
Selpercatinib/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Selpercatinib prolongs the QTc interval.(1) Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(2,3) CLINICAL EFFECTS: The concurrent use of selpercatinib with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(2,3) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(3) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(3) PATIENT MANAGEMENT: Selpercatinib prolongs the QT interval. An increase in QT interval to > 500 ms was measured in 6% of patients and increase in the QT interval of at least 60 ms over baseline was measured in 15% of patients. Monitor patients at significant risk of developing QT prolongation, including patients with known long QT syndromes, clinically significant bradyarrhythmias, and severe or uncontrolled heart failure. Assess QT interval, electrolytes, and TSH at baseline and periodically during treatment. Correct hypokalemia, hypomagnesemia, and hypocalcemia prior to initiation and during treatment. Dose adjustments (1): For grade 3 QT interval prolongation, withhold selpercatinib until recovery to baseline or grade 0 or 1. Resume at a reduced dose. -1st dose reduction: For patients weighing less than 50 kg: 80 mg twice daily. For patients weighing 50 kg or greater: 120 mg twice daily. -2nd dose reduction: For patients weighing less than 50 kg: 40 mg twice daily. For patients weighing 50 kg or greater: 80 mg twice daily. -3rd dose reduction: For patients weighing less than 50 kg: 40 mg once daily. For patients weighing 50 kg or greater: 40 mg twice daily. -For grade 4 QT prolongation, discontinue selpercatinib. DISCUSSION: The effect of selpercatinib on the QT interval was evaluated in a thorough QT study in healthy subjects. The largest mean increase in QT is predicted to be 10.6 ms (upper 90% confidence interval: 12.1 ms) at the mean steady state maximum concentration (Cmax) observed in patients after administration of 160 mg twice daily. The increase in QT was concentration-dependent. Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(2)	RETEVMO
Sunitinib/QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Concurrent use of sunitinib with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The use of sunitinib in patients maintained on agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, advanced age or when receiving concomitant treatment with an inhibitor of CYP3A4.(1,2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: The concurrent use of sunitinib with agents known to prolong the QT interval should be approached with caution.(1) If concurrent therapy is warranted, monitor ECG more frequently and consider obtaining serum calcium, magnesium, and potassium levels at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Sunitinib has been shown to prolong the QT interval in a dose dependent manner. Torsade de pointes has been observed in less than 0.1% of patients receiving sunitinib.(1) A retrospective review of 618 cancer patients treated with 902 administrations of tyrosine kinase inhibitors were evaluated for rate and incidence of QTc prolongation. In patients who received sunitinib, QTc prolongation was identified in 26 (19.4%) with 16 (61.5%) having Grade 1 (QTc 450-480 ms) and 6 (23.1%) having Grade 2 (QTc 480-500 ms). Grade 3 events occurred in 1 (3.8%) having QTc greater than or equal to 500 ms and 1 (3.8%) having QTc change greater than or equal to 60 ms. Ventricular tachycardia was seen in 1 (3.8%) of patients and 1 (3.8%) patient experienced sudden cardiac death.(3) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(4)	SUNITINIB MALATE, SUTENT
Galantamine/QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Galantamine may reduce heart rate by increasing acetylcholine in the heart and increasing vagal tone. Bradycardia has been associated with increased risk of QTc interval prolongation.(1) Concurrent use of galantamine with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(2) CLINICAL EFFECTS: The use of galantamine in patients maintained on agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(2) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, advanced age or when receiving concomitant treatment with an inhibitor of CYP3A4.(3) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(3) PATIENT MANAGEMENT: The UK manufacturer of galantamine states that it should be used with caution in patients treated with drugs that affect the QTc interval.(2) If concurrent therapy is warranted, monitor ECG more frequently and consider obtaining serum calcium, magnesium, and potassium levels at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Therapeutic doses of galantamine have been reported to cause QTc prolongation in patients.(2) An 85 year old male with dementia was restarted on galantamine 8 mg daily after a 2-week treatment interruption due to a syncopal episode that occurred 3 months previously. During his prior syncopal episode, he was hypotensive and bradycardic, but QTc interval was normal. After restarting galantamine, he was found to be hypotension and bradycardiac again, and QTc interval was significantly prolonged to 503 msec, over 60 msec longer than when he was off galantamine. Galantamine was discontinued and his QTc interval returned to baseline.(4) A 47 year old schizophrenic male experienced prolongation of the QTc interval to 518 msec after galantamine was increased from 8 mg daily to 12 mg daily. Although he was also on quetiapine and metoprolol, he had been stable on his other medications. His QTc interval normalized after galantamine was stopped.(5) The European pharmacovigilance (Eudravigilance) database contains 14 reports of torsades de pointe in patients on galantamine as of October 2019.(1) A pharmacovigilance study based on the FDA Adverse Event Reporting System (FAERS) database found that, of a total of 33,626 cases of TdP/QT prolongation reported between January 2004 and September 2022, 54 cases occurred in patients on galantamine. The disproportionality analysis found a ROR = 5.12, 95% CI (3.92,6.68) and a PRR = 5.11, chi-square = 175.44.(6) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(7)	GALANTAMINE ER, GALANTAMINE HBR, GALANTAMINE HYDROBROMIDE, ZUNVEYL
Siponimod/QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Siponimod is a sphingosine-1-phosphate (S1P) receptor modulator. Initiation of siponimod has a negative chronotropic effect. Siponimod blocks the capacity of lymphocytes to egress from lymph nodes, reducing the number of lymphocytes in peripheral blood. The mechanism by which siponimod exerts therapeutic effects in multiple sclerosis is unknown, but may involve reduction of lymphocyte migration into the central nervous system.(1,2) CLINICAL EFFECTS: The heart rate lowering effect of siponimod starts within an hour, and the Day 1 decline is maximal at approximately 3-4 hours. This leads to a mean decrease in heart rate of 5-6 beats per minute after the first dose. The first dose has also been associated with heart block. With continued up-titration, further heart rate decreases are seen on subsequent days, with maximal decrease from Day 1-baseline reached on Day 5-6. Symptomatic bradycardia has been observed. Bradycardia may be associated with an increase in the QTc interval, increasing the risk for torsades de pointes.(1) PREDISPOSING FACTORS: Pre-existing cardiovascular or cerebrovascular disease (e.g. heart failure, ischemic heart disease, history of myocardial infarction, stroke, or heart block), severe untreated sleep apnea, a prolonged QTc interval prior to siponimod initiation, factors associated with QTc prolongation (e.g. hypokalemia, hypomagnesemia), or concomitant treatment with QT prolonging agents may increase risk for cardiovascular toxicity due to siponimod. The risk of QT prolongation or torsades de pointes may also be increased in patients with a history of torsades de pointes, hypocalcemia, bradycardia, female gender, or advanced age.(3) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of the QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(3) PATIENT MANAGEMENT: Prior to initiation of siponimod, obtain an ECG to determine if preexisting conduction abnormalities are present.(1) Advice from a cardiologist is recommended in patients with preexisting heart and cerebrovascular conditions, prolonged QTc interval before or during the 6 hour observation, risk factors for QT prolongation, concurrent therapy with QT prolonging drugs or drugs that slow the heart rate or AV conduction.(1) In patients with heart rate (HR) less than 55 beats per minute (bpm), first- or second-degree AV block, or history of myocardial infarction or heart failure, first dose monitoring is recommended with hourly pulse and blood pressure to monitor for bradycardia for the first 6 hours. ECG monitoring is recommended prior to dosing and at the end of the observation period.(1) Additional US monitoring recommendations include: If HR is less than 45 bpm, the heart rate 6 hours postdose is at the lowest value postdose or if the ECG shows new onset of second degree or higher AV block at the end of the monitoring period, then monitoring should continue until the finding has resolved. If patient requires treatment for symptomatic bradycardia, second-degree or higher AV block, or QTc interval greater than or equal to 500 msec, perform continuous overnight ECG monitoring. Repeat the first dose monitoring strategy for the second dose of siponimod. If a titration dose is missed or if 4 or more consecutive daily doses are missed during maintenance treatment, reinitiate Day 1 of the dose titration and follow titration monitoring recommendations. Patient will need to be observed in the doctor's office or other facility for at least 6 hours after the first dose and after reinitiation if treatment is interrupted or discontinued for certain periods. Consult the prescribing information for full monitoring recommendations. United Kingdom recommendations:(3) In certain patients, it is recommended that an electrocardiogram (ECG) is obtained prior to dosing and at the end of the observation period. If post-dose bradyarrhythmia or conduction-related symptoms occur or if ECG 6 hours post-dose shows new onset second-degree or higher AV block or QTc > 500 msec, appropriate management should be initiated and observation continued until the symptoms/findings have resolved. If pharmacological treatment is required, monitoring should be continued overnight and 6-hour monitoring should be repeated after the second dose. During the first 6 days of treatment, if a titration dose is missed on one day, treatment needs to be re-initiated with a new titration pack. If there is a missed dose after day 6 the prescribed dose should be taken at the next scheduled time; the next dose should not be doubled. If maintenance treatment is interrupted for 4 or more consecutive daily doses, siponimod needs to be re-initiated with a new titration pack.(1,2) DISCUSSION: After the first dose of siponimod, heart rate decrease may begin within an hour. Decline is usually maximal at approximately 3-4 hours. With continued, chronic dosing, heart rate gradually returns to baseline in about 10 days.(1,2) A transient, dose-dependent decrease in heart rate was observed during the initial dosing phase of siponimod, which plateaued at doses greater than or equal to 5 mg, and bradyarrhythmic events (AV blocks and sinus pauses) were detected at a higher incidence under siponimod treatment than placebo. AV blocks and sinus pauses occurred above the recommended dose of 2 mg, with notably higher incidence under non-titrated conditions compared to dose titration conditions.(1)	MAYZENT
Ponesimod/QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Ponesimod is a sphingosine 1-phosphate (S1P) receptor 1 modulator. Initiation of ponesimod has a negative chronotropic effect leading to a mean decrease in heart rate of 6 beats per minute (bpm) after the first dose. The first dose has also been associated with heart block.(1) CLINICAL EFFECTS: After a dose of ponesimod, a decrease in heart rate typically begins within an hour and reaches its nadir within 2-4 hours. The heart rate typically recovers to baseline levels 4-5 hours after administration. All patients recovered from bradycardia. The conduction abnormalities typically were transient, asymptomatic, and resolved within 24 hours. Second- and third-degree AV blocks were not reported. With up-titration after Day 1, the post-dose decrease in heart rate is less pronounced. Bradycardia may be associated with an increase in the QTc interval, increasing the risk for torsades de pointes.(1,2) PREDISPOSING FACTORS: Pre-existing cardiovascular or cerebrovascular disease (e.g. heart failure, ischemic heart disease, history of myocardial infarction, stroke, or heart block), severe untreated sleep apnea, a prolonged QTc interval prior to ponesimod initiation, factors associated with QTc prolongation, or concomitant treatment with QT prolonging agents may increase risk for cardiovascular toxicity due to ponesimod.(1) The risk of QT prolongation or torsades de pointes may also be increased in patients with a history of torsades de pointes, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of the QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: Prior to initiation of ponesimod, obtain an ECG to determine if preexisting conduction abnormalities are present. Ponesimod is generally not recommended in patients who are receiving concurrent treatment with a QT prolonging agent, anti-arrhythmic drugs, or drugs that may decrease heart rate. Consultation with a cardiologist is recommended.(1) In patients with heart rate (HR) less than 55 beats per minute (bpm), first- or second-degree AV block, or history of myocardial infarction or heart failure, monitor patients for 4 hours after the first dose for signs and symptoms of bradycardia with a minimum of hourly pulse and blood pressure measurements. Obtain an ECG in these patients prior to dosing and at the end of the 4-hour observation period.(1) Additional US monitoring recommendations include: If HR is less than 45 bpm, the heart rate 4 hours post-dose is at the lowest value post-dose or if the ECG shows new onset of second degree or higher AV block at the end of the monitoring period, then monitoring should continue until the finding has resolved. If patient requires treatment for symptomatic bradycardia, second-degree or higher AV block, or QTc interval greater than or equal to 500 msec, perform continuous overnight ECG monitoring and repeat the first dose monitoring strategy for the second dose of ponesimod. Consult the prescribing information for full monitoring recommendations. If fewer than 4 consecutive doses are missed during titration: resume treatment with the first missed titration dose and resume the titration schedule at that dose and titration day. If fewer than 4 consecutive doses are missed during maintenance: resume treatment with the maintenance dosage. If 4 or more consecutive daily doses are missed during treatment initiation or maintenance treatment, reinitiate Day 1 of the dose titration (new starter pack) and follow first-dose monitoring recommendations. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: After the first dose of ponesimod, heart rate decrease may begin within the first hour. Decline is usually maximal at approximately 4 hours. With continued, chronic dosing, post-dose decrease in heart rate is less pronounced. Heart rate gradually returns to baseline in about 4-5 hours.(1)	PONVORY
Ozanimod/QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Ozanimod is a sphingosine 1-phosphate (S1P) receptor modulator. Initiation of ozanimod has a negative chronotropic effect leading to a mean decrease in heart rate of 13 beats per minute (bpm) after the first dose. The first dose has also been associated with heart block.(1,2) Ozanimod blocks the capacity of lymphocytes to egress from lymph nodes, reducing the number of lymphocytes in peripheral blood. The mechanism by which ozanimod exerts therapeutic effects in multiple sclerosis is unknown but may involve the reduction of lymphocyte migration into the central nervous system. CLINICAL EFFECTS: The initial heart rate lowering effect of ozanimod usually occurs within 5 hours. With continued up-titration, the maximal heart rate effect of ozanimod occurred on Day 8. Symptomatic bradycardia and heart block, including third degree block, have been observed. Bradycardia may be associated with an increase in the QTc interval, increasing the risk for torsades de pointes.(1,2) PREDISPOSING FACTORS: Pre-existing cardiovascular or cerebrovascular disease (e.g. heart failure, ischemic heart disease, history of myocardial infarction, stroke, or heart block), severe untreated sleep apnea, a prolonged QTc interval prior to ozanimod initiation, factors associated with QTc prolongation (e.g. hypokalemia, hypomagnesemia), or concomitant treatment with QT prolonging agents may increase risk for cardiovascular toxicity due to ozanimod.(1,2) The risk of QT prolongation or torsades de pointes may also be increased in patients with a history of torsades de pointes, hypocalcemia, bradycardia, female gender, or advanced age.(3) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of the QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(3) PATIENT MANAGEMENT: Prior to initiation of ozanimod, obtain an ECG to determine if preexisting conduction abnormalities are present. Patients with preexisting cardiac conditions, significant QT prolongation (QTc >450 msec in males, >470 msec in females), concurrent Class Ia or Class III antiarrhythmics, or receiving concurrent treatment with a QT prolonging agent at the time ozanimod is initiated or resumed should be referred to a cardiologist.(1) The US recommendations state: Dose titration is recommended with initiation of ozanimod due to transient decrease in heart rate and AV conduction delays.(1) United Kingdom recommendations:(2) Due to the risk of transient decreases in HR with the initiation of ozanimod, first dose, 6-hour monitoring for signs and symptoms of symptomatic bradycardia is recommended in patients with resting HR <55 bpm, second-degree [Mobitz type I] AV block or a history of myocardial infarction or heart failure. Patients should be monitored with hourly pulse and blood pressure measurement during this 6-hour period. An ECG prior to and at the end of this 6-hour period is recommended. Additional monitoring after 6 hours is recommended in patients with: heart rate less than 45 bpm, heart rate at the lowest value post-dose (suggesting that the maximum decrease in HR may not have occurred yet), evidence of a new onset second-degree or higher AV block at the 6-hour post dose ECG, or QTc interval greater than 500 msec. In these cases, appropriate management should be initiated and observation continued until the symptoms/findings have resolved. Instruct patients to report any irregular heartbeat, dizziness, or fainting.(2,3) DISCUSSION: After the first dose of ozanimod heart rate decline is usually maximal at approximately 5 hours, returning to baseline at 6 hours. With continued, chronic dosing, maximum heart rate effect occurred on day 8.(1,2)	ZEPOSIA
Midostaurin/QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Concurrent use of midostaurin with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(2) CLINICAL EFFECTS: The use of midostaurin in patients maintained on agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: The US manufacturer of midostaurin recommends caution in patients treated with drugs that affect the QTc interval. If concurrent use with QT prolonging agents is warranted, consider routine interval ECG monitoring of the QT interval.(1) If concurrent therapy is warranted, monitor ECG more frequently and consider obtaining serum calcium, magnesium, and potassium levels at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: In a randomized study of midostaurin 75 mg twice daily for 3 days there was no clinically significant prolongation of QTc interval or relationship between changes in QTc and concentrations for midostaurin and its active metabolites (CGP62221 and CGP52421). However the study noted the duration was not long enough to estimate the effects of the metabolite CGP52421 on the QTc interval.(1) In a pooled analysis in patients with advanced systemic mastocytosis (SM), 4.7% patients had a post-baseline QTcF > 480 ms, no patients had a QTcF > 500 ms, and 6.3% patients had a QTcF > 60 ms compared to baseline.(2) In a randomized placebo-controlled study in patients with acute myeloid leukemia (AML), the proportion of patients with QTc prolongation was higher in the midostaurin group compared to placebo (QTcF > 480 ms: 10.1% vs 5.7%; QTcF > 500 ms: 6.2% vs 2.6%; QTcF > 60 ms change from baseline: 18.4% vs 10.7%).(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(3)	RYDAPT
Panobinostat/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Panobinostat has been observed to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of panobinostat with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: The manufacturer of panobinostat states concurrent use agents known to prolong the QT interval are not recommended. Panobinostat should not be started in patients with a QTcF > 450 msec or clinically significant baseline ST-segment or T-wave abnormalities. If during panobinostat therapy the QTcF increases to > 480 msec, interrupt treatment and correct any electrolyte abnormalities. If QT prolongation does not resolve, permanently discontinue treatment with panobinostat.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: In the randomized multiple myeloma trial, QTc prolongation with values between 451 msec to 480 msec occurred in 10.8% of panobinostat treated patients and patients with values of 481 msec to 500 msec occurred in 1.3% of patients. A maximum QTcF increase from baseline of between 31 msec and 60 msec was reported in 14.5% of patients and a maximum QTcF increase from baseline of >60 msec was reported in 0.8% of patients.(1) Pooled clinical data from over 500 patients treated with single agent panobinostat in multiple indications and at different dose levels has shown that the incidence of CTC Grade 3 QTc prolongation (QTcF >500 msec) was approximately 1% overall and 5% or more at a dose of 60 mg or higher.(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(3)	FARYDAK
Tolterodine/QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Tolterodine has been observed to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1,2) CLINICAL EFFECTS: The concurrent use of tolterodine with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1,2) PREDISPOSING FACTORS: Patients who are CYP2D6 poor metabolizers may be at increased risk.(1,2) The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(3) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(3) PATIENT MANAGEMENT: The manufacturer of tolterodine states concurrent use agents known to prolong the QT interval should be used with caution. Consider close observation in patients with a known history of QT prolongation or patients taking antiarrhythmic medications.(1,2) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: In a study of the effect of tolterodine immediate release tablets, the effect on the QT interval appeared greater for 8 mg/day (two times the therapeutic dose) compared to 4 mg/day. Tolterodine 2 mg BID and tolterodine 4 mg BID increased the QTcF by 5.01 msec (0.28-9.74 msec) and 11.84 msec (7.11-16.58 msec), respectively. The change in QT interval was more pronounced in CYP2D6 poor metabolizers (PM) than extensive metabolizers (EMs).(1,2) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(4)	TOLTERODINE TARTRATE, TOLTERODINE TARTRATE ER
Pacritinib/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Pacritinib has been observed to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of pacritinib with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: The manufacturer of pacritinib states concurrent use with agents known to prolong the QT interval should be avoided. Avoid the use of pacritinib in patients with a baseline QTc > 480 msec. Correct hypokalemia prior to initiation and during therapy with pacritinib.(1) If patients develop QTc prolongation >500 msec or >60 msec from baseline, hold pacritinib. If QTc prolongation resolves to <=480 msec or to baseline within 1 week, resume pacritinib at the same dose. If time to resolution of the QTc interval takes greater than 1 week to resolve, reduce the pacritinib dose.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: In a 24 week clinical study, patients treatment with pacritinib 200 mg twice daily had a change in QTc from baseline of 11 msec (90% CI: 5-17).(1) Pacritinib has been associated with QTc interval prolongation. In clinical trials, patients with QTc prolongation >500 msec occurred in 1.4% of patients in the treatment arm compared to 1% in the control arm. The treatment arm had a greater incidence of an increase in QTc > 60 msec from baseline than the control arm (1.9% vs 1%, respectively). QTc prolongation adverse reactions were higher in the treatment arm than the control group (3.8% vs 2%, respectively).(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(3)	VONJO
Triclabendazole/QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Triclabendazole has been observed to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) Triclabendazole is partially metabolized by CYP1A2. Ciprofloxacin, propafenone, and vemurafenib are CYP1A2 inhibitors and may inhibit the CYP1A2 mediated metabolism of triclabendazole. CLINICAL EFFECTS: The concurrent use of triclabendazole with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) Hepatic impairment and concurrent use of CYP1A2 inhibitors may raise triclabendazole levels and increase the risk of QT prolongation.(1) PATIENT MANAGEMENT: The manufacturer of triclabendazole states concurrent use with agents known to prolong the QT interval should be used with caution. Monitor ECG in patients with a history of QTc prolongation, symptoms of long QT interval, electrolyte imbalances, concurrent CYP1A2 inhibitors, or hepatic impairment. If signs of a cardiac arrhythmia develop, stop treatment with triclabendazole and monitor ECG.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: In a thorough QT study, a dose-dependent prolongation in the QTc interval was observed with triclabendazole. The largest placebo-corrected mean increase in QTc was 9.2 msec (upper limit of confidence interval (UCI): 12.2 msec) following oral administration of 10 mg/kg triclabendazole twice daily (at the recommended dose), and the largest placebo-corrected mean increase in QTc was 21.7 msec (UCI: 24.7 msec) following oral administration of 10 mg/kg triclabendazole twice daily for 3 days (3 times the approved recommended dosing duration).(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(3)	EGATEN
Tacrolimus/QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Tacrolimus has been observed to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of tacrolimus with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: The manufacturer of tacrolimus states concurrent use with agents known to prolong the QT interval should be used with caution and monitoring for QT prolongation is recommended.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Tacrolimus has been associated with QT prolongation.(1) In a kidney transplant population, 98 patients received immunosuppressive management with tacrolimus, cyclosporine, everolimus, or azathioprine. All patients post-transplant had significantly prolonged QTc interval compared to pre-transplant in all groups.(3) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(4)	ASTAGRAF XL, ENVARSUS XR, PROGRAF, TACROLIMUS, TACROLIMUS XL
Adagrasib/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Adagrasib has been shown to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1-3) CLINICAL EFFECTS: The concurrent use of adagrasib with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1-3) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: The US manufacturer of adagrasib states that the concurrent use of QT prolonging agents should be avoided.(1) When concurrent therapy cannot be avoided, obtain ECGs and electrolyte values (serum calcium, magnesium, and potassium) prior to the start of treatment, after initiation of any drug known to prolong the QT interval, and periodically monitor during therapy. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. If patients develop QTc prolongation >500 msec or >60 msec from baseline, withhold adagrasib until QTc interval less than 481 msec or QTc interval returns to baseline. Resume adagrasib at the next lower dose level. If patients develop torsade de pointes, polymorphic ventricular tachycardia, or signs and symptoms of serious or life-threatening arrythmia, permanently discontinue adagrasib.(1) DISCUSSION: Adagrasib has been associated with QTc interval prolongation. Adagrasib increased QTc in a concentration-dependent manner. In patients administered adagrasib 600 mg twice daily, the mean QTcF change from baseline was 18 msec. In the pooled safety population, 6% of 366 patients with at least one post-baseline ECG had an average QTc greater than 501 msec and 11% of patients had a increase from baseline QTc greater than 60 msec.(1) Agents that are linked to this monograph may have been associated with Torsade de Pointes and/or QT prolongation but at this time lack substantial evidence for causing Torsade de Pointes.(3)	KRAZATI
Quizartinib/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Quizartinib has been shown to prolong the QTc interval in a dose- and concentration dependent manner. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1-3) CLINICAL EFFECTS: The concurrent use of quizartinib with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1-3) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: The US manufacturer of quizartinib states that the concurrent use of QT prolonging agents should be avoided.(1) Quizartinib is only available through a restricted REMS program due to the serious risk of QT prolongation, torsades de pointes, and cardiac arrest. The manufacturer recommends monitoring as follows: -Initiate quizartinib only if the QTcF is less than or equal to 450 ms. -During induction and consolidation, monitor ECGs prior to initiation and then at minimum once weekly during treatment. -During maintenance, monitor ECGs prior to initiation and then at minimum once weekly for the first month following dose initiation and escalation and clinically therafter. Dose escalation may occur only if the QTcF is less than or equal to 450 ms. The manufacturer recommends the following dose modifications for adverse reactions: -If the QTcF is 450 ms to 480 ms (Grade 1) - Continue quizartinib dose. -If the QTcF is 481 ms to 500 ms (Grade 2) - Reduce the dose of quizartinib without interruption based on prescribing information. Resume the previous dose in the next cycle if the QTcF has decreased to less than 450 ms. -If the QTcF is greater than 500 ms (Grade 3) - Interrupt quizartinib. Resume at a reduced dose based on prescribing information when the QTcF is less than 450 ms. Maintain the dose of 26.5 mg once daily during maintenance if the QTcF is greater than 500 ms during induction or consolidation. -If recurrent QTcF is greater than 500 ms (Grade 3) - Permanently discontinue quizartinib if QTcF is greater than 500 ms despite dose reduction and correction/elimination of other risk factors. -If TdP, polymorphic ventricular tachycardia, or signs/symptoms of life-threatening arrythmia occur (Grade 4) - Permanently discontinue quizartinib. When concurrent therapy cannot be avoided, obtain ECGs and electrolyte values (serum calcium, magnesium, and potassium) prior to the start of treatment, after initiation of any drug known to prolong the QT interval, and periodically monitor during therapy. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Quizartinib has been associated with QTc interval prolongation, Torsades de Pointes, ventricular arrhythmias, cardiac arrest, and sudden death. Quizartinib increased QTc in a dose- and concentration-dependent manner.(1) In an exposure-response analysis, quizartinib had a predicted concentration-dependent QTc prolongation of 18 to 24 ms (upper bound of 2-sided 90% CI: 21 and 27 ms) at a median steady-state Cmax dose of 26.5 mg and 53 mg during maintenance therapy.(1) In patients administered quizartinib, 2.3% of 265 patients had a QTcF greater than 500 msec and 10% of patients had a increase from baseline QTcF greater than 60 msec.(1) In patients administered quizartinib during the induction phase, torsades de pointes occurred in approximately 0.2% of patients, cardiac arrest occurred in 0.6%, including 0.4% with a fatal outcome, and 0.1% of patients experienced ventricular fibrillation.(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(3)	VANFLYTA
Ofloxacin/QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Ofloxacin has been shown to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1,2) CLINICAL EFFECTS: The concurrent use of ofloxacin with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1,2) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(3) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(3) PATIENT MANAGEMENT: The manufacturer of ofloxacin states that ofloxacin should be used with caution when given with other agents known to prolong the QT interval.(1,2) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: A retrospective database analysis identified case reports of torsades de pointes with ofloxacin.(4) Clinical practice guidelines on the use of systemic fluoroquinolones categorize agents into three groups based on the associated risk of QT prolongation. Ofloxacin is included in group 2: fluoroquinolones associated with a low risk of QT prolongation. Other fluoroquinolones in group 2 include levofloxacin and norfloxacin.(5) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(6)	APOKYN, APOMORPHINE HCL, CESIUM CHLORIDE, ELLENCE, EPIRUBICIN HCL, GATIFLOXACIN SESQUIHYDRATE, GRANISETRON HCL, ISRADIPINE, ONAPGO, RUBRACA, SANCUSO, SUSTOL
Etrasimod/QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Etrasimod is a sphingosine-1-phosphate (S1P) receptor modulator. Initiation of etrasimod has a negative chronotropic effect, which may increase the risk of developing QT prolongation. CLINICAL EFFECTS: Initiation of etrasimod may result in a transient decrease in heart rate. A mean decrease in heart rate of 7.2 (8.98) beats per minute was seen 2 to 3 hours after the first dose. The first dose has also been associated with heart block. Symptomatic bradycardia has been observed. Bradycardia may be associated with an increase in the QTc interval, increasing the risk for torsades de pointes.(1) PREDISPOSING FACTORS: Pre-existing cardiovascular or cerebrovascular disease (e.g. heart failure, ischemic heart disease, history of myocardial infarction, stroke, or heart block), severe untreated sleep apnea, a prolonged QTc interval prior to etrasimod initiation, factors associated with QTc prolongation (e.g. hypokalemia, hypomagnesemia), or concomitant treatment with QT prolonging agents may increase risk for cardiovascular toxicity due to etrasimod. The risk of QT prolongation or torsades de pointes may also be increased in patients with a history of torsades de pointes, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of the QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: Prior to initiation of etrasimod, obtain an ECG to determine if preexisting conduction abnormalities are present.(1) Advice from a cardiologist is recommended in patients with preexisting heart and cerebrovascular conditions, prolonged QTc interval, risk factors for QT prolongation, concurrent therapy with QT prolonging drugs or drugs that slow the heart rate or AV conduction.(1) Monitor blood pressure during treatment.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Initiation of etrasimod may result in a transient decrease in heart rate or transient AV conduction delays.(1) A transient decrease in heart rate was observed during the initial dosing phase of etrasimod and bradyarrhythmic events (AV blocks) were detected at a higher incidence under etrasimod treatment than placebo.(1)	VELSIPITY
Dexmedetomidine Sublingual/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Dexmedetomidine sublingual has been shown to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of dexmedetomidine sublingual with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: The manufacturer of dexmedetomidine sublingual states that concurrent use should be avoided with other agents known to prolong the QTc interval.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: In a QT study, dexmedetomidine sublingual had a concentration dependent effect on the QT interval. The mean QTc (95% confidence interval) increased from baseline by 6 (7) msec with a 120 mcg single dose, 8 (9) msec with 120 mcg followed by 2 additional doses of 60 mcg (total 3 doses), 8 (11) msec with a single 180 mcg dose, and 11 (14) msec with 180 mcg followed by 2 additional doses of 90 mcg (total 3 doses), respectively.(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(3)	IGALMI
Mavorixafor/QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Mavorixafor has been shown to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of mavorixafor with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: The manufacturer of mavorixafor states that concurrent use of mavorixafor with other agents known to prolong the QTc interval should be approached with caution. ECG monitoring is recommended prior to initiation, during concurrent therapy, and as clinically indicated with other agents known to prolong the QTc interval.(1) If QT prolongation occurs, a dose reduction or discontinuation of mavorixafor may be required.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: In a thorough QT study, a dose of mavorixafor 800 mg increased the mean QTc 15.6 msec (upper 90% CI = 19.9 msec). The dose of mavorixafor was 2 times the recommended maximum daily dose.(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(3)	XOLREMDI
Lonafarnib/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Lonafarnib has been shown to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of lonafarnib with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: The manufacturer of lonafarnib states that the concurrent use of QT prolonging agents should be avoided. If concurrent use cannot be avoided, obtain ECGs when initiating, during concurrent use, and as clinically indicated.(1) Lonafarnib dose modification recommendation: if the QTc interval is greater than or equal to 500 msec, withhold lonafarnib until the QTc interval is less than 470 msec, then resume lonafarnib at the same dosage.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities.(1) Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: In a thorough QT study, lonafarnib 200 mg twice daily for 9 consecutive days and a single 200 mg dose on day 10 increased the mean QTc interval by 19 msec (upper bound of 90% confidence interval = 27 msec) on day 10 at 48 hours after administration of the morning dose of lonafarnib 200 mg. The maximum concentration (Cmax) on Day 10 was 2233 ng/ml, which is similar to the mean Cmax of 2695 ng/ml observed in the Hutchinson-Gilford Progeria Syndrome patient population.(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(3)	ZOKINVY
Givinostat/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Givinostat may prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of givinostat with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: The manufacturer of givinostat states that the concurrent use of QT prolonging agents should be avoided. If concurrent use cannot be avoided, obtain ECGs prior to initiating givinostat, during concomitant use, and as clinically indicated.(1) If the QTc interval is greater than 500 ms or the change from baseline is greater than 60 ms, withhold givinostat therapy.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities.(1) Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: In a QT study, the largest mean increase in QTc interval of 13.6 ms (upper confidence interval of 17.1 ms) occurred 5 hours after administration of givinostat 265.8 mg (approximately 5 times the recommended 53.2 mg dose in patients weighing 60 kg or more).(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(3)	DUVYZAT
Revumenib/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Revumenib may prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of revumenib with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: The manufacturer of revumenib states that the concurrent use of QT prolonging agents should be avoided. If concurrent use cannot be avoided, obtain ECGs prior to initiating revumenib, during concomitant use, and as clinically indicated.(1) If the QTc interval is greater than 480 ms, withhold revumenib therapy. Resume revumenib after the QTc interval drops to 480 msec or less.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities.(1) Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: In clinical trials, QTc interval prolongation was reported as an adverse event in 29% of 135 patients treated with the recommended dosage of revumenib; 12% of patients had Grade 3 QTc prolongation. Revumenib increased the QTc interval in a concentration-dependent manner. At the mean steady-state Cmax using the highest approved recommended dosage of revumenib without CYP3A4 inhibitors, QTc increase was predicted to be 27 msec (upper bound of 90% confidence interval = 30 msec). At the steady-state Cmax using the highest approved recommended dosage of revumenib with CYP3A4 inhibitors, QTc increase was predicted to be 19 msec (upper bound of 90% confidence interval = 22 msec).(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(3)	REVUFORJ

The following contraindication information is available for OFLOXACIN (ofloxacin):

Overview
Contraindicated
Severe
Moderate

Drug contraindication overview.

No enhanced Contraindications information available for this drug.

There are 8 contraindications. Absolute contraindication.

Contraindication List
Aortic aneurysm
Congenital long QT syndrome
Dissection of aorta
Ehlers-danlos syndrome
Loeys-dietz syndrome
Marfan syndrome
Myasthenia gravis
Torsades de pointes

There are 14 severe contraindications. Adequate patient monitoring is recommended for safer drug use.

Severe List
Cardiac transplantation
Chronic kidney disease stage 3A (moderate) GFR 45-59 ml/min
Chronic kidney disease stage 3B (moderate) GFR 30-44 ml/min
Chronic kidney disease stage 4 (severe) GFR 15-29 ml/min
Chronic kidney disease stage 5 (failure) GFr<15 ml/min
Clostridioides difficile infection
Glucose-6-phosphate dehydrogenase (g6Pd) deficiency
Hemolytic anemia from pyruvate kinase and g6PD deficiencies
Hypokalemia
Lung transplantation
Prolonged QT interval
Renal transplant
Tendon rupture
Tendonitis

There are 8 moderate contraindications. Clinically significant contraindication, where the condition can be managed or treated before the drug may be given safely.

Moderate List
Dehydration
Diabetes mellitus
Hypoglycemic disorder
Kidney disease with likely reduction in glomerular filtration rate (GFr)
Lower seizure threshold
Peripheral neuropathy
Seizure disorder
Severe hepatic disease

The following adverse reaction information is available for OFLOXACIN (ofloxacin):

Overview
Severe
Less Severe

Adverse reaction overview.

No enhanced Common Adverse Effects information available for this drug.

There are 73 severe adverse reactions.

More Frequent	Less Frequent
None.	Phototoxicity

Rare/Very Rare
Abnormal hepatic function tests Acute cognitive impairment Acute hepatic failure Acute pancreatitis Agitation Agranulocytosis Anaphylaxis Anemia Angioedema Aortic aneurysm Aplastic anemia Arterial dissection Cardiac arrest Cerebral thrombosis Clostridioides difficile infection Dissection of aorta Drug-induced psychosis Dysesthesia Dyspnea Erythema Erythema multiforme Exfoliative dermatitis Hallucinations Hearing loss Hematuria Hemolytic anemia Hepatitis Hyperglycemia Hypersensitivity angiitis Hypersensitivity drug reaction Hypersensitivity pneumonitis Hypoesthesia Hypoglycemic disorder Interstitial nephritis Intracranial hypertension Laryngeal edema Leukopenia Neuromuscular blockade Neutropenic disorder Non-traumatic rupture of achilles tendon Obstructive hyperbilirubinemia Palpitations Pancytopenia Paranoid disorder Peripheral neuropathy Phobia Prolonged QT interval Pruritus of skin Pulmonary edema Renal failure Rhabdomyolysis Rotator cuff tendon rupture Seizure disorder Serum sickness Severe diarrhea Skin rash Stevens-johnson syndrome Suicidal ideation Tachycardia Tendon rupture Tendonitis Thrombocytopenic disorder Thrombotic thrombocytopenic purpura Torsades de pointes Toxic epidermal necrolysis Toxic psychosis Tremor Urinary retention Valvular regurgitation Vasculitis Vasodilation of blood vessels Ventricular arrhythmias

Rare/Very Rare

Abnormal hepatic function tests
Acute cognitive impairment
Acute hepatic failure
Acute pancreatitis
Agitation
Agranulocytosis
Anaphylaxis
Anemia
Angioedema
Aortic aneurysm
Aplastic anemia
Arterial dissection
Cardiac arrest
Cerebral thrombosis
Clostridioides difficile infection
Dissection of aorta
Drug-induced psychosis
Dysesthesia
Dyspnea
Erythema
Erythema multiforme
Exfoliative dermatitis
Hallucinations
Hearing loss
Hematuria
Hemolytic anemia
Hepatitis
Hyperglycemia
Hypersensitivity angiitis
Hypersensitivity drug reaction
Hypersensitivity pneumonitis
Hypoesthesia
Hypoglycemic disorder
Interstitial nephritis
Intracranial hypertension
Laryngeal edema
Leukopenia
Neuromuscular blockade
Neutropenic disorder
Non-traumatic rupture of achilles tendon
Obstructive hyperbilirubinemia
Palpitations
Pancytopenia
Paranoid disorder
Peripheral neuropathy
Phobia
Prolonged QT interval
Pruritus of skin
Pulmonary edema
Renal failure
Rhabdomyolysis
Rotator cuff tendon rupture
Seizure disorder
Serum sickness
Severe diarrhea
Skin rash
Stevens-johnson syndrome
Suicidal ideation
Tachycardia
Tendon rupture
Tendonitis
Thrombocytopenic disorder
Thrombotic thrombocytopenic purpura
Torsades de pointes
Toxic epidermal necrolysis
Toxic psychosis
Tremor
Urinary retention
Valvular regurgitation
Vasculitis
Vasodilation of blood vessels
Ventricular arrhythmias

There are 44 less severe adverse reactions.

More Frequent	Less Frequent
Abdominal pain with cramps Diarrhea Drowsy Gastrointestinal irritation Headache disorder Insomnia Nausea Nervousness Vaginitis	Anorexia Dizziness General weakness Genital organ pruritus Pain Vaginal discharge Vomiting Xerostomia

Rare/Very Rare
Arthralgia Arthritis Ataxia Constipation Delirium Depression Diplopia Disturbance of attention Dyschromia Dysgeusia Dysuria Eosinophilia Fever Memory impairment Muscle spasm Muscle weakness Myalgia Nightmares Paresthesia Photophobia Polyuria Skin photosensitivity Stomatitis Symptoms of anxiety Tinnitus Visual changes Vulvovaginal candidiasis

The following precautions are available for OFLOXACIN (ofloxacin):

Pediatric
Pregnant
Lactation
Geriatric

No enhanced Pediatric Use information available for this drug.

Contraindicated

None

Severe Precaution

None

Management or Monitoring Precaution

None

There are no adequate and controlled studies to date using ofloxacin in pregnant women. Since the drug, like most other fluoroquinolones, causes arthropathy in immature animals, ofloxacin should not be used in pregnant women unless the potential benefits justify the possible risks to the fetus. Reproduction studies in rats and rabbits using oral ofloxacin in dosages up to 810 and 160 mg/kg daily, respectively, have not revealed evidence of teratogenicity.

However, fetotoxicity (decreased fetal body weight and increased fetal mortality) did occur in rats and rabbits receiving oral ofloxacin dosages equivalent to 50 and 10 times the usual human dosage, respectively. In rats receiving ofloxacin dosages of 810 mg/kg daily (more than 50 times the maximum human dosage), retardation in the degree of ossification and minor skeletal variations such as cervical ribs and shortened or absent 13th ribs occurred. Perinatal and postnatal studies in rats using oral dosages up to 360 mg/kg daily revealed a decrease in food intake during gestation and an increase in food and water intake during lactation, but did not reveal evidence of adverse effects on late fetal development, labor, delivery, lactation, neonatal viability, or growth of the offspring.

Ofloxacin is distributed into milk. Because of the potential for serious adverse effects of ofloxacin in nursing infants, a decision should be made whether to discontinue nursing or the drug, taking into account the importance of the drug to the woman.

No enhanced Geriatric Use information available for this drug.

The following icd codes are available for OFLOXACIN (ofloxacin)'s list of indications:

Bacterial urinary tract infection
N30.0	Acute cystitis
N30.00	Acute cystitis without hematuria
N30.01	Acute cystitis with hematuria
N30.9	Cystitis, unspecified
N30.90	Cystitis, unspecified without hematuria
N30.91	Cystitis, unspecified with hematuria
N39.0	Urinary tract infection, site not specified
O23.0	Infections of kidney in pregnancy
O23.00	Infections of kidney in pregnancy, unspecified trimester
O23.01	Infections of kidney in pregnancy, first trimester
O23.02	Infections of kidney in pregnancy, second trimester
O23.03	Infections of kidney in pregnancy, third trimester
O23.1	Infections of bladder in pregnancy
O23.10	Infections of bladder in pregnancy, unspecified trimester
O23.11	Infections of bladder in pregnancy, first trimester
O23.12	Infections of bladder in pregnancy, second trimester
O23.13	Infections of bladder in pregnancy, third trimester
O23.2	Infections of urethra in pregnancy
O23.20	Infections of urethra in pregnancy, unspecified trimester
O23.21	Infections of urethra in pregnancy, first trimester
O23.22	Infections of urethra in pregnancy, second trimester
O23.23	Infections of urethra in pregnancy, third trimester
O23.3	Infections of other parts of urinary tract in pregnancy
O23.30	Infections of other parts of urinary tract in pregnancy, unspecified trimester
O23.31	Infections of other parts of urinary tract in pregnancy, first trimester
O23.32	Infections of other parts of urinary tract in pregnancy, second trimester
O23.33	Infections of other parts of urinary tract in pregnancy, third trimester
O23.4	Unspecified infection of urinary tract in pregnancy
O23.40	Unspecified infection of urinary tract in pregnancy, unspecified trimester
O23.41	Unspecified infection of urinary tract in pregnancy, first trimester
O23.42	Unspecified infection of urinary tract in pregnancy, second trimester
O23.43	Unspecified infection of urinary tract in pregnancy, third trimester
O23.90	Unspecified genitourinary tract infection in pregnancy, unspecified trimester
O23.91	Unspecified genitourinary tract infection in pregnancy, first trimester
O23.92	Unspecified genitourinary tract infection in pregnancy, second trimester
O23.93	Unspecified genitourinary tract infection in pregnancy, third trimester
P39.3	Neonatal urinary tract infection
T83	Complications of genitourinary prosthetic devices, implants and grafts
T83.5	Infection and inflammatory reaction due to prosthetic device, implant and graft in urinary system
T83.51	Infection and inflammatory reaction due to urinary catheter
T83.59	Infection and inflammatory reaction due to prosthetic device, implant and graft in urinary system
T83.6	Infection and inflammatory reaction due to prosthetic device, implant and graft in genital tract
Chlamydia cervicitis
A56.09	Other chlamydial infection of lower genitourinary tract
Chlamydia trachomatis pelvic inflammatory disease
A56.11	Chlamydial female pelvic inflammatory disease
Chlamydia trachomatis urethritis
A56.00	Chlamydial infection of lower genitourinary tract, unspecified
A56.01	Chlamydial cystitis and urethritis
Citrobacter complicated UTI
B96.89	Other specified bacterial agents as the cause of diseases classified elsewhere
N39.0	Urinary tract infection, site not specified
O23.0	Infections of kidney in pregnancy
O23.00	Infections of kidney in pregnancy, unspecified trimester
O23.01	Infections of kidney in pregnancy, first trimester
O23.02	Infections of kidney in pregnancy, second trimester
O23.03	Infections of kidney in pregnancy, third trimester
O23.1	Infections of bladder in pregnancy
O23.10	Infections of bladder in pregnancy, unspecified trimester
O23.11	Infections of bladder in pregnancy, first trimester
O23.12	Infections of bladder in pregnancy, second trimester
O23.13	Infections of bladder in pregnancy, third trimester
O23.2	Infections of urethra in pregnancy
O23.20	Infections of urethra in pregnancy, unspecified trimester
O23.21	Infections of urethra in pregnancy, first trimester
O23.22	Infections of urethra in pregnancy, second trimester
O23.23	Infections of urethra in pregnancy, third trimester
O23.3	Infections of other parts of urinary tract in pregnancy
O23.30	Infections of other parts of urinary tract in pregnancy, unspecified trimester
O23.31	Infections of other parts of urinary tract in pregnancy, first trimester
O23.32	Infections of other parts of urinary tract in pregnancy, second trimester
O23.33	Infections of other parts of urinary tract in pregnancy, third trimester
O23.4	Unspecified infection of urinary tract in pregnancy
O23.40	Unspecified infection of urinary tract in pregnancy, unspecified trimester
O23.41	Unspecified infection of urinary tract in pregnancy, first trimester
O23.42	Unspecified infection of urinary tract in pregnancy, second trimester
O23.43	Unspecified infection of urinary tract in pregnancy, third trimester
T83.5	Infection and inflammatory reaction due to prosthetic device, implant and graft in urinary system
T83.51	Infection and inflammatory reaction due to urinary catheter
T83.510	Infection and inflammatory reaction due to cystostomy catheter
T83.510A	Infection and inflammatory reaction due to cystostomy catheter, initial encounter
T83.511	Infection and inflammatory reaction due to indwelling urethral catheter
T83.511A	Infection and inflammatory reaction due to indwelling urethral catheter, initial encounter
T83.512	Infection and inflammatory reaction due to nephrostomy catheter
T83.512A	Infection and inflammatory reaction due to nephrostomy catheter, initial encounter
T83.518	Infection and inflammatory reaction due to other urinary catheter
T83.518A	Infection and inflammatory reaction due to other urinary catheter, initial encounter
T83.59	Infection and inflammatory reaction due to prosthetic device, implant and graft in urinary system
T83.590	Infection and inflammatory reaction due to implanted urinary neurostimulation device
T83.590A	Infection and inflammatory reaction due to implanted urinary neurostimulation device, initial encounter
T83.591	Infection and inflammatory reaction due to implanted urinary sphincter
T83.591A	Infection and inflammatory reaction due to implanted urinary sphincter, initial encounter
T83.592	Infection and inflammatory reaction due to indwelling ureteral stent
T83.592A	Infection and inflammatory reaction due to indwelling ureteral stent, initial encounter
T83.593	Infection and inflammatory reaction due to other urinary stents
T83.593A	Infection and inflammatory reaction due to other urinary stents, initial encounter
T83.598	Infection and inflammatory reaction due to other prosthetic device, implant and graft in urinary system
T83.598A	Infection and inflammatory reaction due to other prosthetic device, implant and graft in urinary system, initial encounter
Citrobacter cystitis
B96.89	Other specified bacterial agents as the cause of diseases classified elsewhere
N30.0	Acute cystitis
N30.00	Acute cystitis without hematuria
N30.01	Acute cystitis with hematuria
Complicated e. coli UTI
B96.2	Escherichia coli [e. coli ] as the cause of diseases classified elsewhere
B96.20	Unspecified escherichia coli [e. coli] as the cause of diseases classified elsewhere
B96.29	Other escherichia coli [e. coli] as the cause of diseases classified elsewhere
N39.0	Urinary tract infection, site not specified
O23.0	Infections of kidney in pregnancy
O23.00	Infections of kidney in pregnancy, unspecified trimester
O23.01	Infections of kidney in pregnancy, first trimester
O23.02	Infections of kidney in pregnancy, second trimester
O23.03	Infections of kidney in pregnancy, third trimester
O23.1	Infections of bladder in pregnancy
O23.10	Infections of bladder in pregnancy, unspecified trimester
O23.11	Infections of bladder in pregnancy, first trimester
O23.12	Infections of bladder in pregnancy, second trimester
O23.13	Infections of bladder in pregnancy, third trimester
O23.2	Infections of urethra in pregnancy
O23.20	Infections of urethra in pregnancy, unspecified trimester
O23.21	Infections of urethra in pregnancy, first trimester
O23.22	Infections of urethra in pregnancy, second trimester
O23.23	Infections of urethra in pregnancy, third trimester
O23.3	Infections of other parts of urinary tract in pregnancy
O23.30	Infections of other parts of urinary tract in pregnancy, unspecified trimester
O23.31	Infections of other parts of urinary tract in pregnancy, first trimester
O23.32	Infections of other parts of urinary tract in pregnancy, second trimester
O23.33	Infections of other parts of urinary tract in pregnancy, third trimester
O23.4	Unspecified infection of urinary tract in pregnancy
O23.40	Unspecified infection of urinary tract in pregnancy, unspecified trimester
O23.41	Unspecified infection of urinary tract in pregnancy, first trimester
O23.42	Unspecified infection of urinary tract in pregnancy, second trimester
O23.43	Unspecified infection of urinary tract in pregnancy, third trimester
T83.5	Infection and inflammatory reaction due to prosthetic device, implant and graft in urinary system
T83.51	Infection and inflammatory reaction due to urinary catheter
T83.510	Infection and inflammatory reaction due to cystostomy catheter
T83.510A	Infection and inflammatory reaction due to cystostomy catheter, initial encounter
T83.511	Infection and inflammatory reaction due to indwelling urethral catheter
T83.511A	Infection and inflammatory reaction due to indwelling urethral catheter, initial encounter
T83.512	Infection and inflammatory reaction due to nephrostomy catheter
T83.512A	Infection and inflammatory reaction due to nephrostomy catheter, initial encounter
T83.518	Infection and inflammatory reaction due to other urinary catheter
T83.518A	Infection and inflammatory reaction due to other urinary catheter, initial encounter
T83.59	Infection and inflammatory reaction due to prosthetic device, implant and graft in urinary system
T83.590	Infection and inflammatory reaction due to implanted urinary neurostimulation device
T83.590A	Infection and inflammatory reaction due to implanted urinary neurostimulation device, initial encounter
T83.591	Infection and inflammatory reaction due to implanted urinary sphincter
T83.591A	Infection and inflammatory reaction due to implanted urinary sphincter, initial encounter
T83.592	Infection and inflammatory reaction due to indwelling ureteral stent
T83.592A	Infection and inflammatory reaction due to indwelling ureteral stent, initial encounter
T83.593	Infection and inflammatory reaction due to other urinary stents
T83.593A	Infection and inflammatory reaction due to other urinary stents, initial encounter
T83.598	Infection and inflammatory reaction due to other prosthetic device, implant and graft in urinary system
T83.598A	Infection and inflammatory reaction due to other prosthetic device, implant and graft in urinary system, initial encounter
Complicated proteus UTI
B96.4	Proteus (mirabilis) (morganii) as the cause of diseases classified elsewhere
N39.0	Urinary tract infection, site not specified
O23.0	Infections of kidney in pregnancy
O23.00	Infections of kidney in pregnancy, unspecified trimester
O23.01	Infections of kidney in pregnancy, first trimester
O23.02	Infections of kidney in pregnancy, second trimester
O23.03	Infections of kidney in pregnancy, third trimester
O23.1	Infections of bladder in pregnancy
O23.10	Infections of bladder in pregnancy, unspecified trimester
O23.11	Infections of bladder in pregnancy, first trimester
O23.12	Infections of bladder in pregnancy, second trimester
O23.13	Infections of bladder in pregnancy, third trimester
O23.2	Infections of urethra in pregnancy
O23.20	Infections of urethra in pregnancy, unspecified trimester
O23.21	Infections of urethra in pregnancy, first trimester
O23.22	Infections of urethra in pregnancy, second trimester
O23.23	Infections of urethra in pregnancy, third trimester
O23.3	Infections of other parts of urinary tract in pregnancy
O23.30	Infections of other parts of urinary tract in pregnancy, unspecified trimester
O23.31	Infections of other parts of urinary tract in pregnancy, first trimester
O23.32	Infections of other parts of urinary tract in pregnancy, second trimester
O23.33	Infections of other parts of urinary tract in pregnancy, third trimester
O23.4	Unspecified infection of urinary tract in pregnancy
O23.40	Unspecified infection of urinary tract in pregnancy, unspecified trimester
O23.41	Unspecified infection of urinary tract in pregnancy, first trimester
O23.42	Unspecified infection of urinary tract in pregnancy, second trimester
O23.43	Unspecified infection of urinary tract in pregnancy, third trimester
T83.5	Infection and inflammatory reaction due to prosthetic device, implant and graft in urinary system
T83.51	Infection and inflammatory reaction due to urinary catheter
T83.510	Infection and inflammatory reaction due to cystostomy catheter
T83.510A	Infection and inflammatory reaction due to cystostomy catheter, initial encounter
T83.511	Infection and inflammatory reaction due to indwelling urethral catheter
T83.511A	Infection and inflammatory reaction due to indwelling urethral catheter, initial encounter
T83.512	Infection and inflammatory reaction due to nephrostomy catheter
T83.512A	Infection and inflammatory reaction due to nephrostomy catheter, initial encounter
T83.518	Infection and inflammatory reaction due to other urinary catheter
T83.518A	Infection and inflammatory reaction due to other urinary catheter, initial encounter
T83.59	Infection and inflammatory reaction due to prosthetic device, implant and graft in urinary system
T83.590	Infection and inflammatory reaction due to implanted urinary neurostimulation device
T83.590A	Infection and inflammatory reaction due to implanted urinary neurostimulation device, initial encounter
T83.591	Infection and inflammatory reaction due to implanted urinary sphincter
T83.591A	Infection and inflammatory reaction due to implanted urinary sphincter, initial encounter
T83.592	Infection and inflammatory reaction due to indwelling ureteral stent
T83.592A	Infection and inflammatory reaction due to indwelling ureteral stent, initial encounter
T83.593	Infection and inflammatory reaction due to other urinary stents
T83.593A	Infection and inflammatory reaction due to other urinary stents, initial encounter
T83.598	Infection and inflammatory reaction due to other prosthetic device, implant and graft in urinary system
T83.598A	Infection and inflammatory reaction due to other prosthetic device, implant and graft in urinary system, initial encounter
Complicated UTI with pseudomonas aeruginosa
B96.5	Pseudomonas (aeruginosa) (mallei) (pseudomallei) as the cause of diseases classified elsewhere
N39.0	Urinary tract infection, site not specified
O23.0	Infections of kidney in pregnancy
O23.00	Infections of kidney in pregnancy, unspecified trimester
O23.01	Infections of kidney in pregnancy, first trimester
O23.02	Infections of kidney in pregnancy, second trimester
O23.03	Infections of kidney in pregnancy, third trimester
O23.1	Infections of bladder in pregnancy
O23.10	Infections of bladder in pregnancy, unspecified trimester
O23.11	Infections of bladder in pregnancy, first trimester
O23.12	Infections of bladder in pregnancy, second trimester
O23.13	Infections of bladder in pregnancy, third trimester
O23.2	Infections of urethra in pregnancy
O23.20	Infections of urethra in pregnancy, unspecified trimester
O23.21	Infections of urethra in pregnancy, first trimester
O23.22	Infections of urethra in pregnancy, second trimester
O23.23	Infections of urethra in pregnancy, third trimester
O23.3	Infections of other parts of urinary tract in pregnancy
O23.30	Infections of other parts of urinary tract in pregnancy, unspecified trimester
O23.31	Infections of other parts of urinary tract in pregnancy, first trimester
O23.32	Infections of other parts of urinary tract in pregnancy, second trimester
O23.33	Infections of other parts of urinary tract in pregnancy, third trimester
O23.4	Unspecified infection of urinary tract in pregnancy
O23.40	Unspecified infection of urinary tract in pregnancy, unspecified trimester
O23.41	Unspecified infection of urinary tract in pregnancy, first trimester
O23.42	Unspecified infection of urinary tract in pregnancy, second trimester
O23.43	Unspecified infection of urinary tract in pregnancy, third trimester
T83.5	Infection and inflammatory reaction due to prosthetic device, implant and graft in urinary system
T83.51	Infection and inflammatory reaction due to urinary catheter
T83.510	Infection and inflammatory reaction due to cystostomy catheter
T83.510A	Infection and inflammatory reaction due to cystostomy catheter, initial encounter
T83.511	Infection and inflammatory reaction due to indwelling urethral catheter
T83.511A	Infection and inflammatory reaction due to indwelling urethral catheter, initial encounter
T83.512	Infection and inflammatory reaction due to nephrostomy catheter
T83.512A	Infection and inflammatory reaction due to nephrostomy catheter, initial encounter
T83.518	Infection and inflammatory reaction due to other urinary catheter
T83.518A	Infection and inflammatory reaction due to other urinary catheter, initial encounter
T83.59	Infection and inflammatory reaction due to prosthetic device, implant and graft in urinary system
T83.590	Infection and inflammatory reaction due to implanted urinary neurostimulation device
T83.590A	Infection and inflammatory reaction due to implanted urinary neurostimulation device, initial encounter
T83.591	Infection and inflammatory reaction due to implanted urinary sphincter
T83.591A	Infection and inflammatory reaction due to implanted urinary sphincter, initial encounter
T83.592	Infection and inflammatory reaction due to indwelling ureteral stent
T83.592A	Infection and inflammatory reaction due to indwelling ureteral stent, initial encounter
T83.593	Infection and inflammatory reaction due to other urinary stents
T83.593A	Infection and inflammatory reaction due to other urinary stents, initial encounter
T83.598	Infection and inflammatory reaction due to other prosthetic device, implant and graft in urinary system
T83.598A	Infection and inflammatory reaction due to other prosthetic device, implant and graft in urinary system, initial encounter
E. coli cystitis
B96.2	Escherichia coli [e. coli ] as the cause of diseases classified elsewhere
B96.20	Unspecified escherichia coli [e. coli] as the cause of diseases classified elsewhere
B96.29	Other escherichia coli [e. coli] as the cause of diseases classified elsewhere
N30.0	Acute cystitis
N30.00	Acute cystitis without hematuria
N30.01	Acute cystitis with hematuria
E. coli prostatitis
B96.20	Unspecified escherichia coli [e. coli] as the cause of diseases classified elsewhere
B96.29	Other escherichia coli [e. coli] as the cause of diseases classified elsewhere
N41.0	Acute prostatitis
N41.1	Chronic prostatitis
Enterobacter cystitis
B96.89	Other specified bacterial agents as the cause of diseases classified elsewhere
N30.0	Acute cystitis
N30.00	Acute cystitis without hematuria
N30.01	Acute cystitis with hematuria
Gram-negative aerobic bacillary pneumonia
A02.22	Salmonella pneumonia
J15.0	Pneumonia due to klebsiella pneumoniae
J15.5	Pneumonia due to escherichia coli
J15.6	Pneumonia due to other gram-negative bacteria
P23.4	Congenital pneumonia due to escherichia coli
Haemophilus influenzae bronchitis
J20.1	Acute bronchitis due to hemophilus influenzae
Haemophilus influenzae pneumonia
J14	Pneumonia due to hemophilus influenzae
Klebsiella complicated UTI
B96.1	Klebsiella pneumoniae [k. pneumoniae] as the cause of diseases classified elsewhere
N39.0	Urinary tract infection, site not specified
O23.0	Infections of kidney in pregnancy
O23.00	Infections of kidney in pregnancy, unspecified trimester
O23.01	Infections of kidney in pregnancy, first trimester
O23.02	Infections of kidney in pregnancy, second trimester
O23.03	Infections of kidney in pregnancy, third trimester
O23.1	Infections of bladder in pregnancy
O23.10	Infections of bladder in pregnancy, unspecified trimester
O23.11	Infections of bladder in pregnancy, first trimester
O23.12	Infections of bladder in pregnancy, second trimester
O23.13	Infections of bladder in pregnancy, third trimester
O23.2	Infections of urethra in pregnancy
O23.20	Infections of urethra in pregnancy, unspecified trimester
O23.21	Infections of urethra in pregnancy, first trimester
O23.22	Infections of urethra in pregnancy, second trimester
O23.23	Infections of urethra in pregnancy, third trimester
O23.3	Infections of other parts of urinary tract in pregnancy
O23.30	Infections of other parts of urinary tract in pregnancy, unspecified trimester
O23.31	Infections of other parts of urinary tract in pregnancy, first trimester
O23.32	Infections of other parts of urinary tract in pregnancy, second trimester
O23.33	Infections of other parts of urinary tract in pregnancy, third trimester
O23.4	Unspecified infection of urinary tract in pregnancy
O23.40	Unspecified infection of urinary tract in pregnancy, unspecified trimester
O23.41	Unspecified infection of urinary tract in pregnancy, first trimester
O23.42	Unspecified infection of urinary tract in pregnancy, second trimester
O23.43	Unspecified infection of urinary tract in pregnancy, third trimester
T83.5	Infection and inflammatory reaction due to prosthetic device, implant and graft in urinary system
T83.51	Infection and inflammatory reaction due to urinary catheter
T83.510	Infection and inflammatory reaction due to cystostomy catheter
T83.510A	Infection and inflammatory reaction due to cystostomy catheter, initial encounter
T83.511	Infection and inflammatory reaction due to indwelling urethral catheter
T83.511A	Infection and inflammatory reaction due to indwelling urethral catheter, initial encounter
T83.512	Infection and inflammatory reaction due to nephrostomy catheter
T83.512A	Infection and inflammatory reaction due to nephrostomy catheter, initial encounter
T83.518	Infection and inflammatory reaction due to other urinary catheter
T83.518A	Infection and inflammatory reaction due to other urinary catheter, initial encounter
T83.59	Infection and inflammatory reaction due to prosthetic device, implant and graft in urinary system
T83.590	Infection and inflammatory reaction due to implanted urinary neurostimulation device
T83.590A	Infection and inflammatory reaction due to implanted urinary neurostimulation device, initial encounter
T83.591	Infection and inflammatory reaction due to implanted urinary sphincter
T83.591A	Infection and inflammatory reaction due to implanted urinary sphincter, initial encounter
T83.592	Infection and inflammatory reaction due to indwelling ureteral stent
T83.592A	Infection and inflammatory reaction due to indwelling ureteral stent, initial encounter
T83.593	Infection and inflammatory reaction due to other urinary stents
T83.593A	Infection and inflammatory reaction due to other urinary stents, initial encounter
T83.598	Infection and inflammatory reaction due to other prosthetic device, implant and graft in urinary system
T83.598A	Infection and inflammatory reaction due to other prosthetic device, implant and graft in urinary system, initial encounter
Klebsiella cystitis
B96.1	Klebsiella pneumoniae [k. pneumoniae] as the cause of diseases classified elsewhere
N30.0	Acute cystitis
N30.00	Acute cystitis without hematuria
N30.01	Acute cystitis with hematuria
Lower respiratory infection
J15.9	Unspecified bacterial pneumonia
J18.9	Pneumonia, unspecified organism
J22	Unspecified acute lower respiratory infection
Nongonococcal urethritis
A56.01	Chlamydial cystitis and urethritis
N34.1	Nonspecific urethritis
Pneumonia
J15.9	Unspecified bacterial pneumonia
Proteus cystitis
B96.4	Proteus (mirabilis) (morganii) as the cause of diseases classified elsewhere
N30.0	Acute cystitis
N30.00	Acute cystitis without hematuria
N30.01	Acute cystitis with hematuria
Pseudomonas aeruginosa cystitis
B96.5	Pseudomonas (aeruginosa) (mallei) (pseudomallei) as the cause of diseases classified elsewhere
N30.0	Acute cystitis
N30.00	Acute cystitis without hematuria
N30.01	Acute cystitis with hematuria
Skin and skin structure infection
H05.01	Cellulitis of orbit
H05.011	Cellulitis of right orbit
H05.012	Cellulitis of left orbit
H05.013	Cellulitis of bilateral orbits
H05.019	Cellulitis of unspecified orbit
H60.1	Cellulitis of external ear
H60.10	Cellulitis of external ear, unspecified ear
H60.11	Cellulitis of right external ear
H60.12	Cellulitis of left external ear
H60.13	Cellulitis of external ear, bilateral
K12.2	Cellulitis and abscess of mouth
L03	Cellulitis and acute lymphangitis
L03.0	Cellulitis and acute lymphangitis of finger and toe
L03.01	Cellulitis of finger
L03.011	Cellulitis of right finger
L03.012	Cellulitis of left finger
L03.019	Cellulitis of unspecified finger
L03.03	Cellulitis of toe
L03.031	Cellulitis of right toe
L03.032	Cellulitis of left toe
L03.039	Cellulitis of unspecified toe
L03.1	Cellulitis and acute lymphangitis of other parts of limb
L03.11	Cellulitis of other parts of limb
L03.111	Cellulitis of right axilla
L03.112	Cellulitis of left axilla
L03.113	Cellulitis of right upper limb
L03.114	Cellulitis of left upper limb
L03.115	Cellulitis of right lower limb
L03.116	Cellulitis of left lower limb
L03.119	Cellulitis of unspecified part of limb
L03.2	Cellulitis and acute lymphangitis of face and neck
L03.21	Cellulitis and acute lymphangitis of face
L03.211	Cellulitis of face
L03.22	Cellulitis and acute lymphangitis of neck
L03.221	Cellulitis of neck
L03.3	Cellulitis and acute lymphangitis of trunk
L03.31	Cellulitis of trunk
L03.311	Cellulitis of abdominal wall
L03.312	Cellulitis of back [any part except buttock]
L03.313	Cellulitis of chest wall
L03.314	Cellulitis of groin
L03.315	Cellulitis of perineum
L03.316	Cellulitis of umbilicus
L03.317	Cellulitis of buttock
L03.319	Cellulitis of trunk, unspecified
L03.8	Cellulitis and acute lymphangitis of other sites
L03.81	Cellulitis of other sites
L03.811	Cellulitis of head [any part, except face]
L03.818	Cellulitis of other sites
L03.9	Cellulitis and acute lymphangitis, unspecified
L03.90	Cellulitis, unspecified
L08.9	Local infection of the skin and subcutaneous tissue, unspecified
N48.22	Cellulitis of corpus cavernosum and penis
Skin and skin structure proteus infection
B96.4	Proteus (mirabilis) (morganii) as the cause of diseases classified elsewhere
L08.9	Local infection of the skin and subcutaneous tissue, unspecified
Skin and skin structure strep. pyogenes infection
B95.0	Streptococcus, group a, as the cause of diseases classified elsewhere
B95.4	Other streptococcus as the cause of diseases classified elsewhere
L08.89	Other specified local infections of the skin and subcutaneous tissue
L08.9	Local infection of the skin and subcutaneous tissue, unspecified
Staphylococcus aureus skin and skin structure infection
B95.6	Staphylococcus aureus as the cause of diseases classified elsewhere
H60.1	Cellulitis of external ear
H60.10	Cellulitis of external ear, unspecified ear
H60.11	Cellulitis of right external ear
H60.12	Cellulitis of left external ear
H60.13	Cellulitis of external ear, bilateral
J34.0	Abscess, furuncle and carbuncle of nose
L02	Cutaneous abscess, furuncle and carbuncle
L02.0	Cutaneous abscess, furuncle and carbuncle of face
L02.02	Furuncle of face
L02.03	Carbuncle of face
L02.1	Cutaneous abscess, furuncle and carbuncle of neck
L02.12	Furuncle of neck
L02.13	Carbuncle of neck
L02.2	Cutaneous abscess, furuncle and carbuncle of trunk
L02.22	Furuncle of trunk
L02.221	Furuncle of abdominal wall
L02.222	Furuncle of back [any part, except buttock]
L02.223	Furuncle of chest wall
L02.224	Furuncle of groin
L02.225	Furuncle of perineum
L02.226	Furuncle of umbilicus
L02.229	Furuncle of trunk, unspecified
L02.23	Carbuncle of trunk
L02.231	Carbuncle of abdominal wall
L02.232	Carbuncle of back [any part, except buttock]
L02.233	Carbuncle of chest wall
L02.234	Carbuncle of groin
L02.235	Carbuncle of perineum
L02.236	Carbuncle of umbilicus
L02.239	Carbuncle of trunk, unspecified
L02.3	Cutaneous abscess, furuncle and carbuncle of buttock
L02.32	Furuncle of buttock
L02.33	Carbuncle of buttock
L02.4	Cutaneous abscess, furuncle and carbuncle of limb
L02.42	Furuncle of limb
L02.421	Furuncle of right axilla
L02.422	Furuncle of left axilla
L02.423	Furuncle of right upper limb
L02.424	Furuncle of left upper limb
L02.425	Furuncle of right lower limb
L02.426	Furuncle of left lower limb
L02.429	Furuncle of limb, unspecified
L02.43	Carbuncle of limb
L02.431	Carbuncle of right axilla
L02.432	Carbuncle of left axilla
L02.433	Carbuncle of right upper limb
L02.434	Carbuncle of left upper limb
L02.435	Carbuncle of right lower limb
L02.436	Carbuncle of left lower limb
L02.439	Carbuncle of limb, unspecified
L02.5	Cutaneous abscess, furuncle and carbuncle of hand
L02.52	Furuncle hand
L02.521	Furuncle right hand
L02.522	Furuncle left hand
L02.529	Furuncle unspecified hand
L02.53	Carbuncle of hand
L02.531	Carbuncle of right hand
L02.532	Carbuncle of left hand
L02.539	Carbuncle of unspecified hand
L02.6	Cutaneous abscess, furuncle and carbuncle of foot
L02.62	Furuncle of foot
L02.621	Furuncle of right foot
L02.622	Furuncle of left foot
L02.629	Furuncle of unspecified foot
L02.63	Carbuncle of foot
L02.631	Carbuncle of right foot
L02.632	Carbuncle of left foot
L02.639	Carbuncle of unspecified foot
L02.8	Cutaneous abscess, furuncle and carbuncle of other sites
L02.82	Furuncle of other sites
L02.821	Furuncle of head [any part, except face]
L02.828	Furuncle of other sites
L02.83	Carbuncle of other sites
L02.831	Carbuncle of head [any part, except face]
L02.838	Carbuncle of other sites
L02.9	Cutaneous abscess, furuncle and carbuncle, unspecified
L02.92	Furuncle, unspecified
L02.93	Carbuncle, unspecified
L03.01	Cellulitis of finger
L03.011	Cellulitis of right finger
L03.012	Cellulitis of left finger
L03.019	Cellulitis of unspecified finger
L03.03	Cellulitis of toe
L03.031	Cellulitis of right toe
L03.032	Cellulitis of left toe
L03.039	Cellulitis of unspecified toe
L03.1	Cellulitis and acute lymphangitis of other parts of limb
L03.11	Cellulitis of other parts of limb
L03.111	Cellulitis of right axilla
L03.112	Cellulitis of left axilla
L03.113	Cellulitis of right upper limb
L03.114	Cellulitis of left upper limb
L03.115	Cellulitis of right lower limb
L03.116	Cellulitis of left lower limb
L03.119	Cellulitis of unspecified part of limb
L03.2	Cellulitis and acute lymphangitis of face and neck
L03.21	Cellulitis and acute lymphangitis of face
L03.211	Cellulitis of face
L03.22	Cellulitis and acute lymphangitis of neck
L03.221	Cellulitis of neck
L03.3	Cellulitis and acute lymphangitis of trunk
L03.31	Cellulitis of trunk
L03.311	Cellulitis of abdominal wall
L03.312	Cellulitis of back [any part except buttock]
L03.313	Cellulitis of chest wall
L03.314	Cellulitis of groin
L03.315	Cellulitis of perineum
L03.316	Cellulitis of umbilicus
L03.317	Cellulitis of buttock
L03.319	Cellulitis of trunk, unspecified
L03.8	Cellulitis and acute lymphangitis of other sites
L03.81	Cellulitis of other sites
L03.811	Cellulitis of head [any part, except face]
L03.818	Cellulitis of other sites
L03.9	Cellulitis and acute lymphangitis, unspecified
L03.90	Cellulitis, unspecified
L08.89	Other specified local infections of the skin and subcutaneous tissue
L08.9	Local infection of the skin and subcutaneous tissue, unspecified
N48.22	Cellulitis of corpus cavernosum and penis
Streptococcal pneumonia
J13	Pneumonia due to streptococcus pneumoniae
J15.3	Pneumonia due to streptococcus, group B
J15.4	Pneumonia due to other streptococci
Streptococcus pneumoniae bronchitis
B95.3	Streptococcus pneumoniae as the cause of diseases classified elsewhere
J20.2	Acute bronchitis due to streptococcus