Maxi-Tuss Cd

Drug overview for MAXI-TUSS CD (chlorpheniramine maleate/phenylephrine hcl/codeine phosphate):

Generic name: chlorpheniramine maleate/phenylephrine HCl/codeine phosphate
Drug class: Amphetamines/Anorexiants/Stimulants
Therapeutic class: Respiratory Therapy Agents

Chlorpheniramine is an alkylamine (propylamine)-derivative, first Codeine is a phenanthrene-derivative opiate agonist antitussive agent. Phenylephrine hydrochloride is a sympathomimetic amine that predominantly acts by a direct effect on alpha1-adrenergic receptors. generation antihistamine.

No enhanced Uses information available for this drug.

DRUG IMAGES

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The following indications for MAXI-TUSS CD (chlorpheniramine maleate/phenylephrine hcl/codeine phosphate) have been approved by the FDA:

Indications:
Allergic rhinitis
Cold symptoms
Cough
Nasal congestion
Rhinorrhea

Professional Synonyms:
Nasal stuffiness

Dosing information for MAXI-TUSS CD
DRUG LABEL	DOSING TYPE	DOSING INSTRUCTIONS
MAXI-TUSS CD LIQUID	Maintenance	Adults take 5 milliliters by oral route every 4 hours as needed, not to exceed 30 mL in 24 hours

The following drug interaction information is available for MAXI-TUSS CD (chlorpheniramine maleate/phenylephrine hcl/codeine phosphate):

Contraindicated
Severe
Moderate

There are 3 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
Sympathomimetics (Indirect & Mixed Acting)/MAOIs 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: Catecholamine stores increased by MAOIs can be released by indirect acting sympathomimetics such as ephedrine and amphetamine. MAO inhibitors also interfere with gut and liver metabolism of direct acting sympathomimetics (e.g oral phenylephrine). CLINICAL EFFECTS: Concurrent use of MAOIs may result in potentiation of sympathomimetic effects, which may result in headaches, hypertensive crisis, toxic neurological effects, and malignant hyperpyrexia. Fatalities have occurred. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Concurrent use of monoamine oxidase inhibitors and sympathomimetics is contraindicated. The manufacturers of sympathomimetic agents recommend waiting 14 days after discontinuation of MAO inhibitors before initiating the sympathomimetic. DISCUSSION: Indirect acting sympathomimetic amines may cause abrupt elevation of blood pressure when administered to patients taking monoamine oxidase inhibitors, resulting in a potentially fatal hypertensive crisis. Mixed (direct and indirect) acting sympathomimetics have also been shown to interact with monoamine oxidase inhibitors depending on their degree of indirect action. The direct-acting sympathomimetics have not been reported to interact. Dopamine is metabolized by monoamine oxidase, and its pressor effect is enhanced by monoamine oxidase inhibitors. Since procarbazine, an antineoplastic agent, is a weak monoamine oxidase inhibitor, hypertensive reactions may result from its concurrent use with indirect and mixed acting sympathomimetics. Furazolidone, an antibacterial with monoamine oxidase inhibitor action, has also been shown to interact with indirect acting sympathomimetics. Linezolid is another antibacterial with monoamine oxidase inhibitor properties. Metaxalone is a weak inhibitor of MAO. Foods containing large amounts of tyramine have also been implicated in this interaction. Methylene blue, when administered intravenously, has been shown to reach sufficient concentrations to be a potent inhibitor of MAO-A. At recommended dosages, rasagiline, oral selegiline, and transdermal selegiline up to 6mg/day are selective for MAO-B; however, at higher dosages they have been shown to lose their selectivity. 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.	EMSAM, FURAZOLIDONE, MARPLAN, MATULANE, METAXALONE, METHYLENE BLUE, NARDIL, PARNATE, PHENELZINE SULFATE, PROCARBAZINE HCL, PROVAYBLUE, SELEGILINE HCL, TRANYLCYPROMINE SULFATE
Opioid Antagonists/Opioid Analgesics 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: Naltrexone, nalmefene, and samidorphan are opioid antagonists and thus inhibit the effects of opioid analgesics.(1-3) CLINICAL EFFECTS: Concurrent administration or the administration of naltrexone within 7-10 days of opioids may induce acute abstinence syndrome or exacerbate a pre-existing subclinical abstinence syndrome.(1,4) Patients taking naltrexone may not experience beneficial effects of opioid-containing medications.(4) Samidorphan can precipitate opioid withdrawal in patients who are dependent on opioids. In patients who use opioids, delay initiation of samidorphan for a minimum of 7 days after last use of short-acting opioids and 14 days after last use of long-acting opioids.(3) Concurrent use of nalmefene tablets with opioid agonists may prevent the beneficial effects of the opioid.(2) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The manufacturer of naltrexone states that the administration of naltrexone concurrently with opioids or to patients dependent on opioids is contraindicated.(1,4) Patients previously dependent on short-acting opioids should be opioid-free for a minimum of seven to ten days before beginning naltrexone therapy. Patients previously on buprenorphine or methadone may be vulnerable to withdrawal symptoms for as long as 2 weeks.(1,4) The manufacturer of naltrexone states that the naloxone challenge test, described in the naltrexone prescribing information, can be administered to determine if patients are opioid free.(1) The manufacturer of samidorphan states the concurrent use of samidorphan in patients using opioids or undergoing acute opioid withdrawal is contraindicated. Prior to initiating samidorphan, there should be at least a 7-day opioid free interval from the last use of short-acting opioids, and at least a 14-day opioid free interval from the last use of long-acting opioids.(3) The UK manufacturer of nalmefene tablets (for reduction of alcohol consumption) states the concurrent use of opioid analgesics is contraindicated.(2) Suspend the use of nalmefene tablets for 7 days prior to the anticipated use of opioids (e.g., elective surgery).(2) DISCUSSION: A double-blind, randomized, placebo-control study evaluated pain relief and side effects of 35 opioid-naive patients undergoing cesarean section. All patients received spinal anesthesia (bupivacaine and morphine) and were randomized to also receive placebo, naltrexone 3 mg, or naltrexone 6 mg. Patients treated with naltrexone experienced shorter duration of pain relief (not statistically significant), however incidence of opioid-induced side effects was reduced. Patients in the naltrexone 6 mg group had lower rates of pruritus, vomiting, and somnolence (all statistically significant) compared to the placebo group.(5) In a double-blind, randomized, placebo-control trial ten recreational opioid users were studied to determine the effects of hydromorphone (4 mg and 16 mg), tramadol (87.5 mg, 175 mg, and 350 mg), and placebo after pretreatment with naltrexone (50 mg) or placebo. Results show that lower doses of hydromorphone and tramadol acted similar to placebo. Hydromorphone 16 mg alone caused euphoria and miosis which were blocked by naltrexone. Tramadol 350 mg produced a lower magnitude of euphoria and miosis compared to hydromorphone. Naltrexone partially diminished the euphoria caused by tramadol, while it enhanced some of the unpleasant monoaminergic effects (flushing, malaise, vomiting).(6) A case report describes a 28 year-old ex-heroin addict who was stable on methadone 100 mg daily and simultaneously stopped using heroin and began drinking alcohol. He was admitted to the hospital for alcohol detoxification and, by mistake, was given naltrexone 100 mg instead of methadone 100 mg. The patient experienced withdrawal symptoms including chills, agitation, muscle and abdominal pain, generalized piloerection, and dilated pupils. Treatment of withdrawal was titrated to treat symptoms and required administration 78 mg of parenteral hydromorphone, after which the patient experienced relief for the following six hours.(8) Intentional administration of an opioid antagonist, naloxone, with opioid analgesics has been performed with close monitoring to lower required opioid dose by inducing withdrawal. Three case reports describe patients who had improved pain relief on significantly reduced doses of opioid analgesics.(8) In a double-blind controlled trial, 267 trauma patients were randomized to receive 0.05 mg/kg intravenous morphine either alone or in combination with 5 mg naltrexone oral suspension. Evaluated endpoints include reduction of pain and incidence of side effects. Results indicate that ultra-low dose naltrexone does not alter opioid requirements for pain control, but does lower incidence of nausea [2 (1.16%) vs 16 (11.6%), p<0.001].(9)	CONTRAVE, LOTREXONE, LYBALVI, NALTREX, NALTREXONE BASE MONOHYDRATE, NALTREXONE HCL, NALTREXONE HCL DIHYDRATE, NALTREXONE HCL MICRONIZED, OPVEE, VIVITROL
Selected Antihistamines/Selected MAOIs 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: MAOIs prolong and intensify the effects of antihistamines.(1-6) CLINICAL EFFECTS: Concurrent use of antihistamines and a MAOI may result in severe hypotension.(1-6) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Concurrent use of antihistamines and a MAOI is contraindicated.(1-6) DISCUSSION: MAOIs may prolong and intensify the effects of antihistamines, resulting in severe hypotension.(1-6) A case report describes a patient having cyproheptadine added to their phenelzine therapy in an attempt to relieve the patients anorgasmia. The patient began to suddenly experience visual hallucination after taking the cyproheptadine for two months. Once the medication was terminated, the hallucinations stopped occurring within 48 hours.(7) Methylene blue, when administered intravenously, has been shown to reach sufficient concentrations to be a potent inhibitor of MAO-A.(8,9)	AZILECT, EMSAM, FURAZOLIDONE, MARPLAN, MATULANE, METHYLENE BLUE, NARDIL, PARNATE, PHENELZINE SULFATE, PROCARBAZINE HCL, PROVAYBLUE, RASAGILINE MESYLATE, SELEGILINE HCL, TRANYLCYPROMINE SULFATE, XADAGO, ZELAPAR

There are 21 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
Ergot Alkaloids/Sympathomimetics SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Concurrent use of ergot alkaloids and sympathomimetics may result in additive or synergistic effect on peripheral blood vessels. CLINICAL EFFECTS: Concurrent use of ergot alkaloids and sympathomimetics may result in increased blood pressure due to peripheral vasoconstriction. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: When possible, avoid the concurrent use of ergot alkaloids and sympathomimetics. If concurrent use is warranted, monitor blood pressure and for signs of vasoconstriction. Decreasing the dose of one or both drugs may be necessary. DISCUSSION: There have been reports of severe vasoconstriction resulting in gangrene in patients receiving intravenous ergonovine with dopamine or norepinephrine.	DIHYDROERGOTAMINE MESYLATE, ERGOLOID MESYLATES, ERGOMAR, ERGOTAMINE TARTRATE, ERGOTAMINE-CAFFEINE, METHYLERGONOVINE MALEATE, METHYSERGIDE MALEATE, MIGERGOT, MIGRANAL, TRUDHESA
Selected Inhalation Anesthetic Agents/Sympathomimetics SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: The exact mechanism is unknown. The anesthetics produce conduction changes that increase impulse re-entry into the myocardial tissue.(1) The anesthetics' ability to precipitate arrhythmias is enhanced by elevated arterial blood pressure, tachycardia, hypercapnia, and/or hypoxia, events that stimulate the release of endogenous catecholamines.(1) CLINICAL EFFECTS: Concurrent use of inhalation anesthetic agents and sympathomimetics may result in ventricular arrhythmias or sudden blood pressure and heart rate increase during surgery.(2) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Monitor blood pressure and avoid use of sympathomimetics in patients being treated with anesthetics on the day of surgery.(2) Intravenous use of epinephrine during surgery with halothane and related halogenated general anesthetics should be strongly discouraged. When intravenous epinephrine is necessary, nitrous oxide anesthesia supplemented with ether, muscle relaxants, or opioids should be used instead of halothane.(3,4) Epinephrine may safely be used subcutaneously with the following precautions: the patient is adequately ventilated to prevent hypoxia or respiratory acidosis; the total dose of epinephrine is limited to 100 mcg/10 minute period or 300 mcg/hour in adults, 3.5 mcg/Kg in infants, 2.5 mcg/Kg in children up to two years of age, and 1.45 mcg/Kg in children over two years of age; a minimum effective concentration of anesthetic is maintained; the drugs are not co-administered in patients with hypertension or other cardiovascular disorders; and the cardiac rhythm is continuously monitored during and after injection.(3-10) If arrhythmias occur after the administration of the epinephrine, the drugs of choice are lidocaine or propranolol, depending on the type of arrhythmia.(1) DISCUSSION: Administration of epinephrine during halothane anesthesia may may lead to serious ventricular arrhythmias.(3-6,11-18) This has occurred when epinephrine was administered intravenously,(6) when it was administered with lidocaine as a dental block,(11,14) or when it was administered supraperiosteally.(5) Norepinephrine has been shown to interact with halothane in a manner similar to epinephrine.(1) In two case reports, patients were given terbutaline (0.25 to 0.35 mg) for wheezing following induction of anesthesia with halothane. One patient's heart rate increased from 68 to 100 beats/minute, and the ECG showed premature ventricular contractions and bigeminy, while the other patient developed multiple unifocal premature ventricular contractions and bigeminy. The arrhythmias resolved in both patients following lidocaine administration.(19) Although not documented, isoproterenol causes effects on the heart similar to terbutaline(20) and would probably interact with halothane in a similar manner. Other inhalation anesthetics that increase the incidence of arrhythmias with epinephrine include chloroform,(20) methoxyflurane,(20) and enflurane.(12) A similar interaction may be expected between the other inhalation anesthetics and sympathomimetics.	DESFLURANE, FORANE, ISOFLURANE, SEVOFLURANE, SUPRANE, TERRELL, ULTANE
Solid Oral Potassium Tablets/Anticholinergics SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Concentrated potassium may damage the lining of the GI tract. Anticholinergics delay gastric emptying, resulting in the potassium product remaining in the gastrointestinal tract for a longer period of time.(1-16) CLINICAL EFFECTS: Use of solid oral dosage forms of potassium in patients treated with anticholinergics may result in gastrointestinal erosions, ulcers, stenosis and bleeding.(1-16) PREDISPOSING FACTORS: Diseases or conditions which may increase risk for GI damage include: preexisting dysphagia, strictures, cardiomegaly, diabetic gastroparesis, elderly status, or insufficient oral intake to allow dilution of potassium.(1-10,21) Other drugs which may add to risk for GI damage include: nonsteroidal anti-inflammatory drugs (NSAIDs), bisphosphonates, or tetracyclines.(21) PATIENT MANAGEMENT: Regulatory agency and manufacturer recommendations regarding this interaction: - In the US, all solid oral dosage forms (including tablets and extended release capsules) of potassium are contraindicated in patients receiving anticholinergics at sufficient dosages to result in systemic effects.(2-8) Patients receiving such anticholinergic therapy should use a liquid form of potassium chloride.(2) - In Canada, solid oral potassium is contraindicated in any patient with a cause for arrest or delay in tablet/capsule passage through the gastrointestinal tract and the manufacturers recommend caution with concurrent anticholinergic medications.(1,9-10) Evaluate each patient for predisposing factors which may increase risk for GI damage. In patients with multiple risk factors for harm, consider use of liquid potassium supplements, if tolerated. For patients receiving concomitant therapy, assure any potassium dose form is taken after meals with a large glass of water or other fluid. To decrease potassium concentration in the GI tract, limit each dose to 20 meq; if more than 20 meq daily is required, give in divided doses.(2) 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. Patients should be instructed to immediately report any difficulty swallowing, abdominal pain, distention, severe vomiting, or gastrointestinal 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. DISCUSSION: In clinical trials, there was a higher incidence of gastric and duodenal lesions in patients receiving a high dose of a wax-matrix controlled-release formulation with a concurrent anticholinergic agent. Some lesions were asymptomatic and not accompanied by bleeding, as shown by a lack of positive Hemoccult tests.(1-17) Several studies suggest that the incidence of gastric and duodenal lesions may be less with the microencapsulated formulation of potassium chloride.(14-17)	KLOR-CON 10, KLOR-CON 8, KLOR-CON M10, KLOR-CON M15, KLOR-CON M20, POTASSIUM CHLORIDE, POTASSIUM CITRATE ER, UROCIT-K
Solid Oral Potassium Capsules/Anticholinergics SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Concentrated potassium may damage the lining of the GI tract. Anticholinergics delay gastric emptying, resulting in the potassium product remaining in the gastrointestinal tract for a longer period of time.(1-16)) CLINICAL EFFECTS: Use of solid oral dosage forms of potassium in patients treated with anticholinergics may result in gastrointestinal erosions, ulcers, stenosis and bleeding.(1-16) PREDISPOSING FACTORS: Diseases or conditions which may increase risk for GI damage include: preexisting dysphagia, strictures, cardiomegaly, diabetic gastroparesis, elderly status, or insufficient oral intake to allow dilution of potassium.(1-10,21) Other drugs which may add to risk for GI damage include: nonsteroidal anti-inflammatory drugs (NSAIDs), bisphosphonates, or tetracyclines.(21) PATIENT MANAGEMENT: Regulatory agency and manufacturer recommendations regarding this interaction: - In the US, all solid oral dosage forms (including tablets and extended release capsules) of potassium are contraindicated in patients receiving anticholinergics at sufficient dosages to result in systemic effects.(2-8) Patients receiving such anticholinergic therapy should use a liquid form of potassium chloride.(2) - In Canada, solid oral potassium is contraindicated in any patient with a cause for arrest or delay in tablet/capsule passage through the gastrointestinal tract and the manufacturers recommend caution with concurrent anticholinergic medications.(1,9-10) Evaluate each patient for predisposing factors which may increase risk for GI damage. In patients with multiple risk factors for harm, consider use of liquid potassium supplements, if tolerated. For patients receiving concomitant therapy, assure any potassium dose form is taken after meals with a large glass of water or other fluid. To decrease potassium concentration in the GI tract, limit each dose to 20 meq; if more than 20 meq daily is required, give in divided doses.(2) 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. Patients should be instructed to immediately report any difficulty swallowing, abdominal pain, distention, severe vomiting, or gastrointestinal 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. DISCUSSION: In clinical trials, there was a higher incidence of gastric and duodenal lesions in patients receiving a high dose of a wax-matrix controlled-release formulation with a concurrent anticholinergic agent. The lesions were asymptomatic and not accompanied by bleeding, as shown by a lack of positive Hemoccult tests.(1-17) Several studies suggest that the incidence of gastric and duodenal lesions may be less with the microencapsulated formulation of potassium chloride.(14-17)	POTASSIUM CHLORIDE
Mixed;Indirect Sympathomimetics/Selected MAOIs SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Catecholamine stores increased by MAOIs can be released by indirect acting sympathomimetics such as ephedrine and amphetamine. MAO inhibitors also interfere with gut and liver metabolism of direct acting sympathomimetics (e.g oral phenylephrine). CLINICAL EFFECTS: Concurrent use of MAOIs may result in potentiation of sympathomimetic effects, which may result in headaches, hypertensive crisis, toxic neurological effects, and malignant hyperpyrexia. Fatalities have occurred with combinations of sympathomimetics and MAO-A inhibitors. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Concurrent use of MAO-A inhibitors and sympathomimetics is contraindicated. The manufacturers of sympathomimetic agents recommend waiting 14 days after discontinuation of MAO inhibitors before initiating the sympathomimetic. Patients receiving direct or indirect acting sympathomimetics should not receive linezolid unless they are monitored for potential increases in blood pressure. Initial dosages of dopamine and epinephrine should be reduced. At recommended dosages, oral selegiline and transdermal selegiline up to 6mg/day are selective for MAO-B; however, at higher dosages they have been shown to lose their selectivity. Patients receiving higher dosages of selegiline should be considered susceptive to this interaction. DISCUSSION: Indirect acting sympathomimetic amines may cause abrupt elevation of blood pressure when administered to patients taking monoamine oxidase inhibitors, resulting in a potentially fatal hypertensive crisis. Mixed (direct and indirect) acting sympathomimetics have also been shown to interact with monoamine oxidase inhibitors depending on their degree of indirect action. The direct-acting sympathomimetics have not been reported to interact. Dopamine is metabolized by monoamine oxidase, and its pressor effect is enhanced by monoamine oxidase inhibitors. Furazolidone, an antibacterial with monoamine oxidase inhibitor action, has also been shown to interact with indirect acting sympathomimetics. Foods containing large amounts of tyramine have also been implicated in this interaction. A significant pressor response was observed in normal subjects receiving linezolid and tyramine doses of more than 100 mg. Administration of linezolid (600 mg BID for 3 days) with pseudoephedrine (60 mg q 4 hours for 2 doses) increased blood pressure by 32 mmHg. Administration of linezolid (600 mg BID for 3 days) with phenylpropanolamine (25 mg q 4 hours for 2 doses) increased blood pressure by 38 mmHg. 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.	EMSAM, LINEZOLID, LINEZOLID-0.9% NACL, LINEZOLID-D5W, SELEGILINE HCL, XADAGO, ZELAPAR, ZYVOX
Radioactive Iodide/Agents that Affect Iodide SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Many compounds can affect iodide protein binding and alter iodide pharmacokinetics and pharmacodynamics.(1) CLINICAL EFFECTS: Compounds that affect iodide pharmacokinetics and pharmacodynamics may impact the effectiveness of radioactive iodide.(1) PREDISPOSING FACTORS: Compounds that affect iodide pharmacokinetics and pharmacodynamics are expected to have the most impact during therapy using radioactive iodide. Diagnostic procedures would be expected to be impacted less. PATIENT MANAGEMENT: Discuss the use of agents that affect iodide pharmacokinetics and pharmacodynamics with the patient's oncologist.(1) Because indocyanine green contains sodium iodide, the iodine-binding capacity of thyroid tissue may be reduced for at least one week following administration. Do not perform radioactive iodine uptake studies for at least one week following administration of indocyanine green.(2) The manufacturer of iopamidol states administration may interfere with thyroid uptake of radioactive iodine and decrease therapeutic and diagnostic efficacy. Avoid thyroid therapy or testing for up to 6 weeks post administration of iopamidol.(3) DISCUSSION: Many agents interact with radioactive iodine. The average duration of effect is: anticoagulants - 1 week antihistamines - 1 week anti-thyroid drugs, e.g: carbimazole, methimazole, propylthiouracil - 3-5 days corticosteroids - 1 week iodide-containing medications, e.g: amiodarone - 1-6 months expectorants - 2 weeks Lugol solution - 3 weeks saturated solution of potassium iodine - 3 weeks vitamins - 10-14 days iodide-containing X-ray contrast agents - up to 1 year lithium - 4 weeks phenylbutazone - 1-2 weeks sulfonamides - 1 week thyroid hormones (natural or synthetic), e.g.: thyroxine - 4 weeks tri-iodothyronine - 2 weeks tolbutamide - 1 week topical iodide - 1-9 months (1)	ADREVIEW, JEANATOPE, MEGATOPE, SODIUM IODIDE I-123
Sodium Oxybate/Codeine; Tramadol SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Oxybate by itself may be associated with severe somnolence or respiratory depression. Concurrent use with other CNS depressants may further increase the risk for respiratory depression or loss of consciousness.(1-3) Codeine and tramadol are converted to their more active opioid metabolites (morphine and O-desmethyltramadol respectively) by CYP2D6. CLINICAL EFFECTS: Concurrent use of sodium oxybate and opioids such as tramadol, or alcohol may further increase the risk for respiratory depression and profound sedation, syncope or coma.(1,2) Fatalities have been reported.(3) PREDISPOSING FACTORS: Based upon FDA evaluation of deaths in patients taking sodium oxybate, risk factors may include: use of multiple drugs which depress the CNS, more rapid than recommended oxybate dose titration, exceeding the maximum recommended oxybate dose, and prescribing for unapproved uses such as fibromyalgia, insomnia or migraine. Note that in oxybate clinical trials for narcolepsy 78% - 85% of patients were also receiving concomitant CNS stimulants.(1-3) In patients receiving codeine or tramadol, ultrarapid metabolizers of CYP2D6 are more likely to have higher than normal systemic concentrations of the active opioid.(4) Other patients at high risk from this interaction include: adolescents between 12 and 18 years who are obese or have conditions such as obstructive sleep apnea or severe lung disease, which may increase the risk of respiratory depression; and breastfeeding women (due to the risk of serious adverse reactions in breastfed infants).(5) PATIENT MANAGEMENT: Avoid use of oxybate when concomitant opioids, benzodiazepines, sedating antidepressants, sedating antipsychotics, general anesthetics, or muscle relaxants, particularly when predisposing risk factors are present. If combination use is required, dose reduction or discontinuation of one or more CNS depressants should be considered. If short term use of an opioid or general anesthetic is required, consider interruption of sodium oxybate treatment.(1,2) Codeine and tramadol are converted to their active opioid metabolites by CYP2D6. Ultrarapid metabolizers of CYP2D6 more rapidly convert codeine or tramadol to their active metabolites (morphine and o-desmethyltramadol respectively) and so are more likely to have higher than normal systemic concentrations of the active opioid. Respiratory depression can occur at any time during opioid therapy, especially during therapy initiation and following dosage increases. Consider this risk when using concurrently with other agents that may cause CNS depression.(6) Discuss naloxone with all patients when prescribing or renewing an opioid analgesic or medicine to treat opioid use disorder (OUD). Consider prescribing naloxone to patients prescribed medicines to treat OUD or opioid analgesics (such as those taking CNS depressants) who are at increased risk of opioid overdose and when a patient has household members/close contacts at risk for accidental overdose.(7) DISCUSSION: The FDA evaluated sodium oxybate postmarket fatal adverse event reports from the FDA Adverse Event Reporting System(AERS) and from the manufacturer. Although report documentation was not always optimal or complete, useful information was obtained. Factors which may have contributed to fatal outcome: concomitant use of one or more drugs which depress the CNS, more rapid than recommended oxybate dose titration, exceeding the maximum recommended oxybate dose, and prescribing for unapproved uses such as fibromyalgia, insomnia or migraine. FDA reported the case of a 5-year-old patient who received one dose of tramadol following a tonsillectomy and experienced slow, difficult breathing requiring emergency intervention and hospitalization. The child was subsequently found to be an ultrarapid metabolizer of CYP2D6.(4) Many deaths occurred in patients with serious psychiatric disorders such as depression and substance abuse. Other concomitant diseases may have also contributed to respiratory and CNS depressant effects of oxybate.(3)	LUMRYZ, LUMRYZ STARTER PACK, SODIUM OXYBATE, XYREM, XYWAV
Selected Direct-Acting Sympathomimetics/Tricyclic Compounds SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Unknown. However, it is speculated that direct-acting sympathomimetic amines have an enhanced effect due to tricyclic blockage of norepinephrine reuptake. CLINICAL EFFECTS: Increased effect of direct acting sympathomimetics. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Consider avoiding the concurrent use of direct-acting sympathomimetics and tricyclic compounds. If concurrent use of direct-acting sympathomimetics and tricyclic compounds is warranted, the initial dose of the sympathomimetic should be lowered and the patient should be monitored for adverse cardiovascular effects. Use of tricyclic compounds and other sympathomimetics should be approached with caution. DISCUSSION: Epinephrine and other direct-acting sympathomimetic amines exert enhanced cardiovascular effects (e.g., arrhythmias, hypertension, and tachycardia) in individuals concurrently receiving or previously treated with tricyclic antidepressants. Other direct and mixed acting sympathomimetic amines have also been reported to interact with tricyclic antidepressants. These include norepinephrine, phenylephrine, dopamine, and methoxamine. Protriptyline, amitriptyline, and desipramine have also been reported to interact with direct-acting sympathomimetics.	AMITRIPTYLINE HCL, AMOXAPINE, ANAFRANIL, CHLORDIAZEPOXIDE-AMITRIPTYLINE, CLOMIPRAMINE HCL, DESIPRAMINE HCL, DOXEPIN HCL, IMIPRAMINE HCL, IMIPRAMINE PAMOATE, NORPRAMIN, NORTRIPTYLINE HCL, PAMELOR, PERPHENAZINE-AMITRIPTYLINE, PROTRIPTYLINE HCL, SILENOR, TRIMIPRAMINE MALEATE
Opioids (Cough and Cold)/Benzodiazepines SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Concurrent use of opioids and benzodiazepines may result in additive CNS depression.(1) CLINICAL EFFECTS: Concurrent use of opioids and other CNS depressants, such as benzodiazepines, may result in profound sedation, respiratory depression, coma, and/or death.(1) PREDISPOSING FACTORS: Concurrent use of alcohol or other CNS depressants may increase the risk of adverse effects. PATIENT MANAGEMENT: Avoid prescribing opioid-including cough medications for patients taking CNS depressants such as benzodiazepines.(1) Respiratory depression can occur at any time during opioid therapy, especially during therapy initiation and following dosage increases. Consider this risk when using concurrently with other agents that may cause CNS depression.(2) If concurrent use is necessary, monitor patients for unusual dizziness or lightheadedness, extreme sleepiness, slowed or difficult breathing, or unresponsiveness.(1) Discuss naloxone with all patients when prescribing or renewing an opioid analgesic or medicine to treat opioid use disorder (OUD). Consider prescribing naloxone to patients prescribed medicines to treat OUD or opioid analgesics (such as those taking CNS depressants) who are at increased risk of opioid overdose and when a patient has household members/close contacts at risk for accidental overdose.(3) DISCUSSION: Between 2002 and 2014, the number of patients receiving an opioid analgesic increased 8%, from 75 million to 81 million patients, and the number of patients receiving a benzodiazepine increased 31%, from 23 million to 30 million patients. During this time, the proportion of patients receiving concurrent therapy increased 31%, from 23 million to 30 million patients.(4) From 2004 to 2011, the rate of nonmedical use-related emergency room visits involving both opioids and benzodiazepines increased from 11 to 34.2 per 100,000 and drug overdose deaths involving both opioids and benzodiazepines increased from 0.6 to 1.7 per 100,000. The proportion of prescription opioid analgesic deaths which also involved benzodiazepines increased from 18% to 31% during this time.(5) A prospective observational cohort study in North Carolina found that the rates of overdose death among patients co-dispensed opioid analgesics and benzodiazepines were 10 times higher than patients receiving opioid analgesics alone.(6) A case-cohort study of VA data from 2004-2009 found that the risk of death from overdose increased with concomitant opioid analgesics and benzodiazepines. Compared to patients with no history of benzodiazepines, patients with a history of benzodiazepine use (hazard ratio [HR] = 2.33) and patients with a current benzodiazepine prescription (HR=3.86) had an increased risk of fatal overdose.(7) A study found that opioid analgesics contributed to 77% of deaths in which benzodiazepines were determined to be a cause of death and that benzodiazepines contributed to 30% of deaths in which opioid analgesics were determined to be a cause of death. This study also found that other CNS depressants (including barbiturates, antipsychotic and neuroleptic drugs, antiepileptic and antiparkinsonian drugs, anesthetics, autonomic nervous system drugs, and muscle relaxants) were contributory to death in many cases where opioid analgesics were also implicated.(8) A study found that alcohol was involved in 18.5% of opioid analgesic abuse-related ED visits and 22.1 percent of opioid analgesic-related deaths.(9) A study of 315,428 privately insured patients who filled at least one prescription for an opioid from 2001 to 2013 were enrolled in a retrospective study. Concurrent use of a benzodiazepine was recorded as having at least one day of overlap in a given calendar year. Baseline characteristics among opioid users with concurrent use of a benzodiazepine were older (44.5 v. 42.4, p<0.001), less likely to be men (35% v. 43%, p<0.001), and had a higher prevalence rate of every comorbidity examined (p<0.001). The proportion of opioid users with concurrent benzodiazepine use nearly doubled from 9% in 2001 to 17% in 2013. The primary outcome was an emergency room visit or inpatient admission for opioid overdose within a calendar year. Among all opioid users, the annual adjusted incidence for the primary outcome was 1.16% without concurrent benzodiazepine use compared to 2.42% with concurrent benzodiazepine use (OR 2.14; 95% CI 2.05-2.24; p<0.001). Intermittent opioid users (1.45% v. 1.02%; OR 1.42; 95% CI 1.33-1.51; p<0.001) and chronic opioid users (5.36% v. 3.13%; OR 1.81; 95% CI 1.67-1.96; p<0.001) also experienced a higher adjusted incidence of the primary outcome with concurrent benzodiazepine use compared to without concurrent benzodiazepine use, respectively.(10) In a nested case-control study of adults with a new opioid dispensing between 2010-2018, patients with concurrent use of an opioid with a benzodiazepine were significantly more likely to have opioid-related overdose compared to patients receiving opioids, benzodiazepines, or neither (OR 9.28; 95% CI 7.87, 10.93). Longer concurrent use of 1-7, 8-30, and 31-90 days was associated with 4.6, 12.1, and 26.7-fold higher likelihood of opioid-related overdose (p<0.01). Patients with overlapping prescriptions during previous 0-30, 31-60, and 61-90 days were 13.2, 6.0, and 3.2-times more likely to experience an overdose (p<0.01).(11)	ALPRAZOLAM, ALPRAZOLAM ER, ALPRAZOLAM INTENSOL, ALPRAZOLAM ODT, ALPRAZOLAM XR, ATIVAN, BYFAVO, CHLORDIAZEPOXIDE HCL, CHLORDIAZEPOXIDE-AMITRIPTYLINE, CHLORDIAZEPOXIDE-CLIDINIUM, CLOBAZAM, CLONAZEPAM, CLORAZEPATE DIPOTASSIUM, DIAZEPAM, DORAL, ESTAZOLAM, FLURAZEPAM HCL, HALCION, KLONOPIN, LIBRAX, LORAZEPAM, LORAZEPAM INTENSOL, LOREEV XR, MIDAZOLAM, MIDAZOLAM HCL, MIDAZOLAM HCL-0.8% NACL, MIDAZOLAM HCL-0.9% NACL, MIDAZOLAM HCL-D5W, MIDAZOLAM HCL-NACL, MIDAZOLAM-0.9% NACL, MIDAZOLAM-NACL, MKO (MIDAZOLAM-KETAMINE-ONDAN), NAYZILAM, ONFI, OXAZEPAM, QUAZEPAM, RESTORIL, SYMPAZAN, TEMAZEPAM, TRIAZOLAM, VALIUM, VALTOCO, XANAX, XANAX XR
Opioids (Cough and Cold)/Sleep Drugs SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Concurrent use of opioids and sleep drugs or tranquilizers may result in additive CNS depression and sleep-related disorders.(1) CLINICAL EFFECTS: Concurrent use of opioids and other CNS depressants, such as sleep drugs or tranquilizers, may result in profound sedation, respiratory depression, coma, and/or death.(1) Concurrent use of opioids with eszopiclone, zaleplon, or zolpidem may increase the risk of sleep-related disorders including central sleep apnea and sleep-related hypoxemia, and complex sleep behaviors like sleepwalking, sleep driving, and other activities while not fully awake. Rarely, serious injuries or death have resulted from complex sleep behaviors.(2) PREDISPOSING FACTORS: Concurrent use of alcohol or other CNS depressants may increase the risk of adverse effects. PATIENT MANAGEMENT: Avoid prescribing opioid-including cough medications for patients taking CNS depressants such as sleep drugs or tranquilizers.(1) Respiratory depression can occur at any time during opioid therapy, especially during therapy initiation and following dosage increases. Consider this risk when using concurrently with other agents that may cause CNS depression.(3) If concurrent use is necessary, monitor patients for unusual dizziness or lightheadedness, extreme sleepiness, slowed or difficult breathing, or unresponsiveness.(1) Eszopiclone, zaleplon, and zolpidem are contraindicated in patients who have had a previous episode of complex sleep behavior.(2) Discuss naloxone with all patients when prescribing or renewing an opioid analgesic or medicine to treat opioid use disorder (OUD). Consider prescribing naloxone to patients prescribed medicines to treat OUD or opioid analgesics (such as those taking CNS depressants) who are at increased risk of opioid overdose and when a patient has household members/close contacts at risk for accidental overdose.(4) DISCUSSION: Between 2002 and 2014, the number of patients receiving an opioid analgesic increased 8%, from 75 million to 81 million patients, and the number of patients receiving a benzodiazepine increased 31%, from 23 million to 30 million patients. During this time, the proportion of patients receiving concurrent therapy increased 31%, from 23 million to 30 million patients.(5) From 2004 to 2011, the rate of nonmedical use-related emergency room visits involving both opioids and benzodiazepines increased from 11 to 34.2 per 100,000 and drug overdose deaths involving both opioids and benzodiazepines increased from 0.6 to 1.7 per 100,000. The proportion of prescription opioid analgesic deaths which also involved benzodiazepines increased from 18% to 31% during this time.(6) A prospective observational cohort study in North Carolina found that the rates of overdose death among patients co-dispensed opioid analgesics and benzodiazepines were 10 times higher than patients receiving opioid analgesics alone.(7) A case-cohort study of VA data from 2004-2009 found that the risk of death from overdose increased with concomitant opioid analgesics and benzodiazepines. Compared to patients with no history of benzodiazepines, patients with a history of benzodiazepine use (hazard ratio [HR] = 2.33) and patients with a current benzodiazepine prescription (HR=3.86) had an increased risk of fatal overdose.(8) A study found that opioid analgesics contributed to 77% of deaths in which benzodiazepines were determined to be a cause of death and that benzodiazepines contributed to 30% of deaths in which opioid analgesics were determined to be a cause of death. This study also found that other CNS depressants (including barbiturates, antipsychotic and neuroleptic drugs, antiepileptic and antiparkinsonian drugs, anesthetics, autonomic nervous system drugs, and muscle relaxants) were contributory to death in many cases where opioid analgesics were also implicated.(9) A study found that alcohol was involved in 18.5% of opioid analgesic abuse-related ED visits and 22.1 percent of opioid analgesic-related deaths.(10) As of April 2019, the FDA had identified 66 cases of complex sleep behaviors with eszopiclone, zaleplon, or zolpidem, of which 20 cases resulted in death and the remainder resulted in serious injuries. It was not reported how many of the cases involved concomitant use of other CNS depressants.(2)	AMBIEN, AMBIEN CR, BELSOMRA, DAYVIGO, EDLUAR, ESZOPICLONE, LUNESTA, QUVIVIQ, RAMELTEON, ROZEREM, ZALEPLON, ZOLPIDEM TARTRATE, ZOLPIDEM TARTRATE ER
Opioids (Cough and Cold)/Muscle Relaxants SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Concurrent use of opioids and muscle relaxants may result in additive CNS depression.(1) CLINICAL EFFECTS: Concurrent use of opioids and other CNS depressants, such as muscle relaxants, may result in profound sedation, respiratory depression, coma, and/or death.(1) PREDISPOSING FACTORS: Concurrent use of alcohol or other CNS depressants may increase the risk of adverse effects. PATIENT MANAGEMENT: Avoid prescribing opioid-including cough medications for patients taking CNS depressants such as muscle relaxants.(1) Respiratory depression can occur at any time during opioid therapy, especially during therapy initiation and following dosage increases. Consider this risk when using concurrently with other agents that may cause CNS depression.(2) If concurrent use is necessary, monitor patients for unusual dizziness or lightheadedness, extreme sleepiness, slowed or difficult breathing, or unresponsiveness.(1) Discuss naloxone with all patients when prescribing or renewing an opioid analgesic or medicine to treat opioid use disorder (OUD). Consider prescribing naloxone to patients prescribed medicines to treat OUD or opioid analgesics (such as those taking CNS depressants) who are at increased risk of opioid overdose and when a patient has household members/close contacts at risk for accidental overdose.(3) DISCUSSION: Between 2002 and 2014, the number of patients receiving an opioid analgesic increased 8%, from 75 million to 81 million patients, and the number of patients receiving a benzodiazepine increased 31%, from 23 million to 30 million patients. During this time, the proportion of patients receiving concurrent therapy increased 31%, from 23 million to 30 million patients.(4) A retrospective cohort study compared the risk of opioid overdose associated with concomitant use of opioids and skeletal muscle relaxants versus opioid use alone. The study examined two types of opioid users (naive opioid use and prevalent opioid use) with and without exposure to skeletal muscle relaxants. The adjusted hazard ratios (HR) were 1.09 and 1.26 in the naive and prevalent opioid user cohorts, respectively, generating a combined estimate of 1.21. The risk increased with treatment duration (less than or equal to 14 days: 0.91; 15-60 days: 1.37; and greater than 60 days: 1.80) and for the use of baclofen and carisoprodol (HR 1.83 and 1.84, respectively). Elevated risk was associated with concomitant users with daily opioid dose greater than 50 mg and benzodiazepine use (HR 1.50 and 1.39, respectively).(5) From 2004 to 2011, the rate of nonmedical use-related emergency room visits involving both opioids and benzodiazepines increased from 11 to 34.2 per 100,000 and drug overdose deaths involving both opioids and benzodiazepines increased from 0.6 to 1.7 per 100,000. The proportion of prescription opioid analgesic deaths which also involved benzodiazepines increased from 18% to 31% during this time.(6) A prospective observational cohort study in North Carolina found that the rates of overdose death among patients co-dispensed opioid analgesics and benzodiazepines were 10 times higher than patients receiving opioid analgesics alone.(7) A case-cohort study of VA data from 2004-2009 found that the risk of death from overdose increased with concomitant opioid analgesics and benzodiazepines. Compared to patients with no history of benzodiazepines, patients with a history of benzodiazepine use (hazard ratio [HR] = 2.33) and patients with a current benzodiazepine prescription (HR=3.86) had an increased risk of fatal overdose.(8) A study found that opioid analgesics contributed to 77% of deaths in which benzodiazepines were determined to be a cause of death and that benzodiazepines contributed to 30% of deaths in which opioid analgesics were determined to be a cause of death. This study also found that other CNS depressants (including barbiturates, antipsychotic and neuroleptic drugs, antiepileptic and antiparkinsonian drugs, anesthetics, autonomic nervous system drugs, and muscle relaxants) were contributory to death in many cases where opioid analgesics were also implicated.(9) A study found that alcohol was involved in 18.5% of opioid analgesic abuse-related ED visits and 22.1 percent of opioid analgesic-related deaths.(10)	AMRIX, BACLOFEN, CARISOPRODOL, CARISOPRODOL-ASPIRIN, CARISOPRODOL-ASPIRIN-CODEINE, CHLORZOXAZONE, CYCLOBENZAPRINE HCL, CYCLOBENZAPRINE HCL ER, CYCLOPAK, CYCLOTENS, DANTRIUM, DANTROLENE SODIUM, FEXMID, FLEQSUVY, LORZONE, LYVISPAH, MEPROBAMATE, METHOCARBAMOL, NORGESIC, NORGESIC FORTE, ORPHENADRINE CITRATE, ORPHENADRINE CITRATE ER, ORPHENADRINE-ASPIRIN-CAFFEINE, ORPHENGESIC FORTE, OZOBAX, OZOBAX DS, REVONTO, ROBAXIN, RYANODEX, SOMA, TANLOR, TIZANIDINE HCL, VANADOM, ZANAFLEX
Opioids (Cough and Cold)/Antipsychotics; Phenothiazines SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Concurrent use of opioids and antipsychotics, including phenothiazine derivatives, may result in additive CNS depression.(1) CLINICAL EFFECTS: Concurrent use of opioids and other CNS depressants, such as antipsychotics, including phenothiazine derivatives, may result in profound sedation, respiratory depression, coma, and/or death.(1) PREDISPOSING FACTORS: Concurrent use of alcohol or other CNS depressants may increase the risk of adverse effects. PATIENT MANAGEMENT: Avoid prescribing opioid-including cough medications for patients taking CNS depressants such as antipsychotics, including phenothiazine derivatives.(1) Respiratory depression can occur at any time during opioid therapy, especially during therapy initiation and following dosage increases. Consider this risk when using concurrently with other agents that may cause CNS depression.(2) If concurrent use is necessary, monitor patients for unusual dizziness or lightheadedness, extreme sleepiness, slowed or difficult breathing, or unresponsiveness.(1) Discuss naloxone with all patients when prescribing or renewing an opioid analgesic or medicine to treat opioid use disorder (OUD). Consider prescribing naloxone to patients prescribed medicines to treat OUD or opioid analgesics (such as those taking CNS depressants) who are at increased risk of opioid overdose and when a patient has household members/close contacts at risk for accidental overdose.(3) DISCUSSION: A nested case-control study looked at the relationship between antipsychotic use and risk of acute respiratory failure. Current use of antipsychotics was associated with a 2.33-fold increase in risk of respiratory failure compared to no use of antipsychotics. The risk was also significantly increased in patients with recent use of antipsychotics (within the past 15-30 days, OR = 1.79) and recent past use (within 31-90 days OR = 1.41). The risk increased with higher doses and longer duration of use.(4) Between 2002 and 2014, the number of patients receiving an opioid analgesic increased 8%, from 75 million to 81 million patients, and the number of patients receiving a benzodiazepine increased 31%, from 23 million to 30 million patients. During this time, the proportion of patients receiving concurrent therapy increased 31%, from 23 million to 30 million patients.(5) From 2004 to 2011, the rate of nonmedical use-related emergency room visits involving both opioids and benzodiazepines increased from 11 to 34.2 per 100,000 and drug overdose deaths involving both opioids and benzodiazepines increased from 0.6 to 1.7 per 100,000. The proportion of prescription opioid analgesic deaths which also involved benzodiazepines increased from 18% to 31% during this time.(6) A prospective observational cohort study in North Carolina found that the rates of overdose death among patients co-dispensed opioid analgesics and benzodiazepines were 10 times higher than patients receiving opioid analgesics alone.(7) A case-cohort study of VA data from 2004-2009 found that the risk of death from overdose increased with concomitant opioid analgesics and benzodiazepines. Compared to patients with no history of benzodiazepines, patients with a history of benzodiazepine use (hazard ratio [HR] = 2.33) and patients with a current benzodiazepine prescription (HR=3.86) had an increased risk of fatal overdose.(8) A study found that opioid analgesics contributed to 77% of deaths in which benzodiazepines were determined to be a cause of death and that benzodiazepines contributed to 30% of deaths in which opioid analgesics were determined to be a cause of death. This study also found that other CNS depressants (including barbiturates, antipsychotic and neuroleptic drugs, antiepileptic and antiparkinsonian drugs, anesthetics, autonomic nervous system drugs, and muscle relaxants) were contributory to death in many cases where opioid analgesics were also implicated.(9) A study found that alcohol was involved in 18.5% of opioid analgesic abuse-related ED visits and 22.1 percent of opioid analgesic-related deaths.(10)	ABILIFY, ABILIFY ASIMTUFII, ABILIFY MAINTENA, ADASUVE, ARIPIPRAZOLE, ARIPIPRAZOLE ODT, ARISTADA, ARISTADA INITIO, ASENAPINE MALEATE, BARHEMSYS, CAPLYTA, CHLORPROMAZINE HCL, CLOZAPINE, CLOZAPINE ODT, CLOZARIL, COMPAZINE, COMPRO, DROPERIDOL, ERZOFRI, FANAPT, FLUPHENAZINE DECANOATE, FLUPHENAZINE HCL, HALDOL DECANOATE 100, HALDOL DECANOATE 50, HALOPERIDOL, HALOPERIDOL DECANOATE, HALOPERIDOL DECANOATE 100, HALOPERIDOL LACTATE, INVEGA, INVEGA HAFYERA, INVEGA SUSTENNA, INVEGA TRINZA, LATUDA, LOXAPINE, LURASIDONE HCL, MOLINDONE HCL, NUPLAZID, OLANZAPINE, OLANZAPINE ODT, OLANZAPINE-FLUOXETINE HCL, OPIPZA, PALIPERIDONE ER, PERPHENAZINE, PERPHENAZINE-AMITRIPTYLINE, PERSERIS, PHENERGAN, PIMOZIDE, PROCHLORPERAZINE, PROCHLORPERAZINE EDISYLATE, PROCHLORPERAZINE MALEATE, PROMETHAZINE HCL, PROMETHAZINE HCL-0.9% NACL, PROMETHAZINE VC, PROMETHAZINE-CODEINE, PROMETHAZINE-DM, PROMETHAZINE-PHENYLEPHRINE HCL, PROMETHEGAN, QUETIAPINE FUMARATE, QUETIAPINE FUMARATE ER, REXULTI, RISPERDAL, RISPERDAL CONSTA, RISPERIDONE, RISPERIDONE ER, RISPERIDONE ODT, RYKINDO, SAPHRIS, SECUADO, SEROQUEL, SEROQUEL XR, THIORIDAZINE HCL, THIORIDAZINE HYDROCHLORIDE, THIOTHIXENE, TRIFLUOPERAZINE HCL, UZEDY, VERSACLOZ, VRAYLAR, ZYPREXA
Iobenguane I 123/Agents that Affect Catecholamines SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Many compounds that reduce catecholamine uptake or that deplete catecholamine stores may interfere with iobenguane uptake into cells.(1) CLINICAL EFFECTS: Compounds that reduce catecholamine uptake or that deplete catecholamine stores may interfere with imaging completed with iobenguane.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Discuss the use of agents that affect catecholamines. Discontinue drugs that reduce catecholamine uptake or deplete catecholamine stores prior to imaging with iobenguane. Before imaging with iobenguane, discontinue agents that affect catecholamines for at least 5 biological half-lives, as clinically tolerated.(1) DISCUSSION: Many agents may reduce catecholamine uptake or deplete catecholamine stores.(1) Examples include: - CNS stimulants or amphetamines (e.g. cocaine, methylphenidate, dextroamphetamine) - norepinephrine and dopamine reuptake inhibitors (e.g. phentermine) - norepinephrine and serotonin reuptake inhibitors (e.g. tramadol) - monoamine oxidase inhibitors (e.g. phenelzine, linezolid) - central monoamine depleting drugs (e.g. reserpine) - non-select beta adrenergic blocking drugs (e.g. labetalol) - alpha agonists or alpha/beta agonists (e.g. pseudoephedrine, phenylephrine, ephedrine, phenylpropanolamine, naphazoline) - tricyclic antidepressants or norepinephrine reuptake inhibitors (e.g. amitriptyline, bupropion, duloxetine, mirtazapine, venlafaxine) - botanicals that may inhibit reuptake of norepinephrine, serotonin or dopamine (e.g. ephedra, ma huang, St. John's Wort, yohimbine)	ADREVIEW
Clozapine/Anticholinergics SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Clozapine has potent anticholinergic properties and inhibits serotonin receptors, including 5-HT3.(1-4) Both of these properties may cause inhibition of gastrointestinal (GI) smooth muscle contraction, resulting in decreased peristalsis.(3,4) These effects may be compounded by concurrent use of anticholinergic agents.(1-6) CLINICAL EFFECTS: Concurrent use of clozapine with other anticholinergic agents may increase the risk of constipation (common) and serious bowel complications (uncommon), including complete bowel obstruction, fecal impaction, paralytic ileus and intestinal ischemia or infarction.(1-6) PREDISPOSING FACTORS: The risk for serious bowel complications is higher with increasing age, higher frequency of constipation, and in patients on higher doses of clozapine or multiple anticholinergic agents.(1,5) PATIENT MANAGEMENT: Avoid the use of other anticholinergic agents with clozapine.(1-6) If concurrent use is necessary, evaluate the patient's bowel function regularly. Monitor for symptoms of constipation and GI hypomotility, including having bowel movements less than three times weekly or less than usual, difficulty having a bowel movement or passing gas, nausea, vomiting, and abdominal pain or distention.(2) Consider a prophylactic laxative in those with a history of constipation or bowel obstruction.(2) Review patient medication list for other anticholinergic agents. When possible, decrease the dosage or number of prescribed anticholinergic agents, particularly in the elderly. Counsel the patient about the importance of maintaining adequate hydration. Encourage regular exercise and eating a high-fiber diet.(2) DISCUSSION: In a prospective cohort study of 26,720 schizophrenic patients in the Danish Central Psychiatric Research Registry, the odds ratio (OR) for ileus was 1.99 with clozapine and 1.48 with anticholinergics. The OR for fatal ileus was 6.73 with clozapine and 5.88 with anticholinergics. Use of anticholinergics with 1st generation antipsychotics (FGA) increased the risk of ileus compare to FGA alone, but this analysis was not done with clozapine.(5) A retrospective cohort study of 24,970 schizophrenic patients from the Taiwanese National Health Insurance Research Database found that the hazard ratio (HR) for clozapine-induced constipation increased from 1.64 when clozapine is used alone, to 2.15 when used concomitantly with anticholinergics. However, there was no significant difference in the HR for ileus when clozapine is used with and without anticholinergics (1.95 and 2.02, respectively).(6) In the French Pharmacovigilance Database, 7 of 38 cases of antipsychotic-associated ischemic colitis or intestinal necrosis involved clozapine, and 5 of these cases involved use of concomitant anticholinergic agents. Three patients died, one of whom was on concomitant anticholinergics.(3) In a case series, 4 of 9 cases of fatal clozapine-associated GI dysfunction involved concurrent anticholinergic agents.(4)	CLOZAPINE, CLOZAPINE ODT, CLOZARIL, VERSACLOZ
Gabapentinoids/Opioids (Cough & Cold) SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Opioid-induced reduction in GI motility may increase the absorption of gabapentin and pregabalin.(1) Gabapentin and pregabalin may reverse opioid-induced tolerance of respiratory depression.(2) Concurrent use may result in profound sedation, respiratory depression, coma, and/or death.(3) CLINICAL EFFECTS: Concurrent use of opioids may result in elevated levels of and toxicity from gabapentin and pregabalin, including profound sedation, respiratory depression, coma, and/or death.(1-7) PREDISPOSING FACTORS: Patients who are elderly, are taking other CNS depressants, have decreased renal function, and/or have conditions that reduce lung function (e.g. Chronic Obstructive Pulmonary Disease [COPD]) may be at a higher risk of this interaction. PATIENT MANAGEMENT: Avoid prescribing opioid-including cough medications for patients taking CNS depressants.(8) If concurrent use is necessary, limit the dosages and duration of each drug to the minimum possible while achieving the desired clinical effect. If starting a gabapentinoid with an opioid analgesic, prescribe a lower initial dose of the gabapentinoid than indicated in the absence of an opioid and titrate based upon clinical response. If an opioid analgesic is indicated in a patient already taking a gabapentinoid, prescribe a lower dose of the opioid and titrate based upon clinical response.(1) Respiratory depression can occur at any time during opioid therapy, especially during therapy initiation and following dosage increases. Consider this risk when using concurrently with other agents that may cause CNS depression.(9) Monitor patients receiving concurrent therapy for unusual dizziness or lightheadedness, extreme sleepiness, slowed or difficult breathing, or unresponsiveness.(1) DISCUSSION: In a study in 12 healthy males, administration of a single dose of morphine (60 mg sustained release) increased the area-under-curve (AUC) of a single dose of gabapentin (600 mg) by 44%.(1,3,4) There were no affects on the pharmacokinetics of morphine.(1,3,4) The combination of gabapentin plus morphine increased pain tolerance over the combination of morphine plus placebo. Side effects were not significantly different between morphine plus placebo and morphine plus gabapentin.(1) A retrospective, case-control study of opioid users in Ontario, Canada between August 1, 1997 and December 31, 2013 who died of an opioid-related cause matched cases to up to 4 controls who also used opioids. Use of gabapentin in the 120 days prior to death resulted in a significant increase in odds of opioid-related death (OR 1.99, CI=1.61-2.47, p<0.001), compared to opioid use alone. Use of moderate dose (900 mg to 1,799 mg daily) or high dose (>= 1,800 mg daily) gabapentin increased the odds of opioid-related death 60% compared to opioid use without gabapentin. Review of gabapentin prescriptions from calendar year 2013 found that 46% of gabapentin users received at least 1 opioid prescription.(3) Among 49 case reports submitted to FDA over a 5 year period (2012-2017), 12 people died from respiratory depression with gabapentinoids. Two randomized, double-blind, placebo-controlled clinical trials in healthy people, three observational studies, and several studies in animals were reviewed. A trial showed that using pregabalin alone and using it with an opioid pain reliever can depress breathing function. Three observational studies showed a relationship between gabapentinoids given before surgery and respiratory depression occurring after surgery. Several animal studies also showed that pregabalin plus opioids can depress respiratory function.(7) A retrospective cohort study evaluated the risk of mortality among Medicare beneficiaries aged 65 and older who were taking gabapentin with or without concurrent use of opioids. All-cause mortality in gabapentin users compared to duloxetine users was 12.16 per 1,000 person years vs. 9.94 per 1,000 person years, respectively. Adjusted for covariates, the risk of all-cause mortality among gabapentin users on high-dose opioids was more than double the control group (hazard ratio (HR) 2.03, CI=1.19-3.46).(10)	GABAPENTIN, GABAPENTIN ER, GABARONE, GRALISE, HORIZANT, LYRICA, LYRICA CR, NEURONTIN, PREGABALIN, PREGABALIN ER
Eluxadoline/Anticholinergics; Opioids SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Eluxadoline is a mixed mu-opioid and kappa-opioid agonist and delta-opioid antagonist and may alter or slow down gastrointestinal transit.(1) CLINICAL EFFECTS: Constipation related adverse events that sometimes required hospitalization have been reported, including the development of intestinal obstruction, intestinal perforation, and fecal impaction.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Avoid use with other drugs that may cause constipation. If concurrent use is necessary, evaluate the patient's bowel function regularly. Monitor for symptoms of constipation and GI hypomotility, including having bowel movements less than three times weekly or less than usual, difficulty having a bowel movement or passing gas, nausea, vomiting, and abdominal pain or distention.(1) Instruct patients to stop eluxadoline and immediately contact their healthcare provider if they experience severe constipation. Loperamide may be used occasionally for acute management of severe diarrhea, but must be discontinued if constipation develops.(1) DISCUSSION: In phase 3 clinical trials, constipation was the most commonly reported adverse reaction (8%). Approximately 50% of constipation events occurred within the first 2 weeks of treatment while the majority occurred within the first 3 months of therapy. Rates of severe constipation were less than 1% in patients receiving eluxadoline doses of 75 mg and 100 mg.(1)	VIBERZI
Selected Opioids (Cough and Cold)/Metaxalone SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Concurrent use of opioids and muscle relaxants may result in additive CNS depression.(1) CLINICAL EFFECTS: Concurrent use of opioids and other CNS depressants, such as muscle relaxants, may result in profound sedation, respiratory depression, coma, and/or death.(1) PREDISPOSING FACTORS: Concurrent use of alcohol or other CNS depressants may increase the risk of adverse effects. PATIENT MANAGEMENT: Avoid prescribing opioid-including cough medications for patients taking CNS depressants such as muscle relaxants.(1) Respiratory depression can occur at any time during opioid therapy, especially during therapy initiation and following dosage increases. Consider this risk when using concurrently with other agents that may cause CNS depression.(2) If concurrent use is necessary, monitor patients for unusual dizziness or lightheadedness, extreme sleepiness, slowed or difficult breathing, or unresponsiveness.(1) Discuss naloxone with all patients when prescribing or renewing an opioid analgesic or medicine to treat opioid use disorder (OUD). Consider prescribing naloxone to patients prescribed medicines to treat OUD or opioid analgesics (such as those taking CNS depressants) who are at increased risk of opioid overdose and when a patient has household members/close contacts at risk for accidental overdose.(3) DISCUSSION: Between 2002 and 2014, the number of patients receiving an opioid analgesic increased 8%, from 75 million to 81 million patients, and the number of patients receiving a benzodiazepine increased 31%, from 23 million to 30 million patients. During this time, the proportion of patients receiving concurrent therapy increased 31%, from 23 million to 30 million patients.(4) A retrospective cohort study compared the risk of opioid overdose associated with concomitant use of opioids and skeletal muscle relaxants versus opioid use alone. The study examined two types of opioid users (naive opioid use and prevalent opioid use) with and without exposure to skeletal muscle relaxants. The adjusted hazard ratios (HR) were 1.09 and 1.26 in the naive and prevalent opioid user cohorts, respectively, generating a combined estimate of 1.21. The risk increased with treatment duration (less than or equal to 14 days: 0.91; 15-60 days: 1.37; and greater than 60 days: 1.80) and for the use of baclofen and carisoprodol (HR 1.83 and 1.84, respectively). Elevated risk was associated with concomitant users with daily opioid dose greater than 50 mg and benzodiazepine use (HR 1.50 and 1.39, respectively).(5) From 2004 to 2011, the rate of nonmedical use-related emergency room visits involving both opioids and benzodiazepines increased from 11 to 34.2 per 100,000 and drug overdose deaths involving both opioids and benzodiazepines increased from 0.6 to 1.7 per 100,000. The proportion of prescription opioid analgesic deaths which also involved benzodiazepines increased from 18% to 31% during this time.(6) A prospective observational cohort study in North Carolina found that the rates of overdose death among patients co-dispensed opioid analgesics and benzodiazepines were 10 times higher than patients receiving opioid analgesics alone.(7) A case-cohort study of VA data from 2004-2009 found that the risk of death from overdose increased with concomitant opioid analgesics and benzodiazepines. Compared to patients with no history of benzodiazepines, patients with a history of benzodiazepine use (hazard ratio [HR] = 2.33) and patients with a current benzodiazepine prescription (HR=3.86) had an increased risk of fatal overdose.(8) A study found that opioid analgesics contributed to 77% of deaths in which benzodiazepines were determined to be a cause of death and that benzodiazepines contributed to 30% of deaths in which opioid analgesics were determined to be a cause of death. This study also found that other CNS depressants (including barbiturates, antipsychotic and neuroleptic drugs, antiepileptic and antiparkinsonian drugs, anesthetics, autonomic nervous system drugs, and muscle relaxants) were contributory to death in many cases where opioid analgesics were also implicated.(9) A study found that alcohol was involved in 18.5% of opioid analgesic abuse-related ED visits and 22.1 percent of opioid analgesic-related deaths.(10)	METAXALONE
Selected Opioids (Cough and Cold)/Selected Tranquilizers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Concurrent use of opioids and tranquilizers may result in additive CNS depression.(1) CLINICAL EFFECTS: Concurrent use of opioids and other CNS depressants such as tranquilizers may result in profound sedation, respiratory depression, coma, and/or death.(1) PREDISPOSING FACTORS: Concurrent use of alcohol or other CNS depressants may increase the risk of adverse effects. PATIENT MANAGEMENT: Avoid prescribing opioid-including cough medications for patients taking CNS depressants such tranquilizers.(1) Respiratory depression can occur at any time during opioid therapy, especially during therapy initiation and following dosage increases. Consider this risk when using concurrently with other agents that may cause CNS depression.(2) If concurrent use is necessary, monitor patients for unusual dizziness or lightheadedness, extreme sleepiness, slowed or difficult breathing, or unresponsiveness.(1) Discuss naloxone with all patients when prescribing or renewing an opioid analgesic or medicine to treat opioid use disorder (OUD). Consider prescribing naloxone to patients prescribed medicines to treat OUD or opioid analgesics (such as those taking CNS depressants) who are at increased risk of opioid overdose and when a patient has household members/close contacts at risk for accidental overdose.(3) DISCUSSION: Between 2002 and 2014, the number of patients receiving an opioid analgesic increased 8%, from 75 million to 81 million patients, and the number of patients receiving a benzodiazepine increased 31%, from 23 million to 30 million patients. During this time, the proportion of patients receiving concurrent therapy increased 31%, from 23 million to 30 million patients.(4) From 2004 to 2011, the rate of nonmedical use-related emergency room visits involving both opioids and benzodiazepines increased from 11 to 34.2 per 100,000 and drug overdose deaths involving both opioids and benzodiazepines increased from 0.6 to 1.7 per 100,000. The proportion of prescription opioid analgesic deaths which also involved benzodiazepines increased from 18% to 31% during this time.(5) A prospective observational cohort study in North Carolina found that the rates of overdose death among patients co-dispensed opioid analgesics and benzodiazepines were 10 times higher than patients receiving opioid analgesics alone.(6) A case-cohort study of VA data from 2004-2009 found that the risk of death from overdose increased with concomitant opioid analgesics and benzodiazepines. Compared to patients with no history of benzodiazepines, patients with a history of benzodiazepine use (hazard ratio [HR] = 2.33) and patients with a current benzodiazepine prescription (HR=3.86) had an increased risk of fatal overdose.(7) A study found that opioid analgesics contributed to 77% of deaths in which benzodiazepines were determined to be a cause of death and that benzodiazepines contributed to 30% of deaths in which opioid analgesics were determined to be a cause of death. This study also found that other CNS depressants (including barbiturates, antipsychotic and neuroleptic drugs, antiepileptic and antiparkinsonian drugs, anesthetics, autonomic nervous system drugs, and muscle relaxants) were contributory to death in many cases where opioid analgesics were also implicated.(8) A study found that alcohol was involved in 18.5% of opioid analgesic abuse-related ED visits and 22.1 percent of opioid analgesic-related deaths.(9)	PENTOBARBITAL SODIUM
Mixed;Indirect Sympathomimetics/Rasagiline SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Catecholamine stores increased by MAOIs can be released by indirect acting sympathomimetics such as ephedrine and amphetamine. MAO inhibitors also interfere with gut and liver metabolism of direct acting sympathomimetics (e.g oral phenylephrine). CLINICAL EFFECTS: Concurrent use of MAOIs may result in potentiation of sympathomimetic effects, which may result in headaches, hypertensive crisis, toxic neurological effects, and malignant hyperpyrexia. Hypertensive crisis has been reported in patients taking recommended doses of rasagiline with sympathomimetic agents. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: At recommended dosages, rasagiline is selective for MAO-B; however, at higher dosages it has been shown to lose its selectivity. Patients receiving higher dosages of rasagiline should be considered susceptive to this interaction. Concurrent use should be approached with caution. DISCUSSION: Indirect acting sympathomimetic amines may cause abrupt elevation of blood pressure when administered to patients taking monoamine oxidase inhibitors, resulting in a potentially fatal hypertensive crisis. Mixed (direct and indirect) acting sympathomimetics have also been shown to interact with monoamine oxidase inhibitors depending on their degree of indirect action. The direct-acting sympathomimetics have not been reported to interact. Dopamine is metabolized by monoamine oxidase, and its pressor effect is enhanced by monoamine oxidase inhibitors.	AZILECT, RASAGILINE MESYLATE
Glucagon (Diagnostic)/Anticholinergics SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Glucagon and anticholinergic agents may have additive effects on inhibition of gastrointestinal motility.(1) CLINICAL EFFECTS: Concurrent use of glucagon with anticholinergic agents may increase the risk of gastrointestinal hypomotility, including constipation and bowel complications.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Concurrent use of glucagon as a diagnotic aid is not recommended with the use of anticholinergic agents.(1) If concurrent use is necessary, evaluate the patient's bowel function. Monitor for symptoms of constipation and gastrointestinal hypomotility. DISCUSSION: Both glucagon and anticholinergic agents may have additive effects on inhibition of gastrointestinal motility and increase the risk of gastrointestinal adverse effects.(1)	GLUCAGON HCL
Sodium Iodide I 131/Agents that Affect Iodide SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Many compounds can affect iodide protein binding and alter iodide pharmacokinetics and pharmacodynamics.(1,2) CLINICAL EFFECTS: Compounds that affect iodide pharmacokinetics and pharmacodynamics may impact the effectiveness of radioactive iodide.(1,2) PREDISPOSING FACTORS: Compounds that affect iodide pharmacokinetics and pharmacodynamics are expected to have the most impact during therapy using radioactive iodide. Diagnostic procedures would be expected to be impacted less. PATIENT MANAGEMENT: Discuss the use of agents that affect iodide pharmacokinetics and pharmacodynamics with the patient's oncologist.(1,2) Because indocyanine green contains sodium iodide, the iodine-binding capacity of thyroid tissue may be reduced for at least one week following administration. Do not perform radioactive iodine uptake studies for at least one week following administration of indocyanine green.(3) The manufacturer of iopamidol states administration may interfere with thyroid uptake of radioactive iodine and decrease therapeutic and diagnostic efficacy. Avoid thyroid therapy or testing for up to 6 weeks post administration of iopamidol.(4) DISCUSSION: Many agents interact with radioactive iodine. The average duration of effect is: anticoagulants - 1 week antihistamines - 1 week anti-thyroid drugs, e.g: carbimazole, methimazole, propylthiouracil - 3-5 days corticosteroids - 1 week iodide-containing medications, e.g: amiodarone - 1-6 months expectorants - 2 weeks Lugol solution - 3 weeks saturated solution of potassium iodine - 3 weeks vitamins - 10-14 days iodide-containing X-ray contrast agents - up to 1 year lithium - 4 weeks phenylbutazone - 1-2 weeks sulfonamides - 1 week thyroid hormones (natural or synthetic), e.g.: thyroxine - 4 weeks tri-iodothyronine - 2 weeks tolbutamide - 1 week topical iodide - 1-9 months (1,2)	HICON, SODIUM IODIDE I-131

There are 11 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
Sympathomimetics (Direct, Mixed-Acting)/Guanethidine SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Direct or mixed-acting sympathomimetics may inhibit uptake of guanethidine at the adrenergic neuron. CLINICAL EFFECTS: Decreased antihypertensive effectiveness. Effects may be seen for several days after discontinuation of the direct or mixed-acting sympathomimetic. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Avoid concomitant administration of these drugs. If both drugs are administered, adjust the guanethidine dose as needed based on blood pressure. DISCUSSION: Documentation supports routine monitoring of this interaction. It should be noted that this interaction can occur quickly.	GUANETHIDINE HEMISULFATE
Sympathomimetics/Rauwolfia Alkaloids SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Reserpine depletes catecholamine stores within the peripheral vascular adrenergic nerve endings, thus indirect acting sympathomimetics are unable to trigger the release of catecholamines. The reserpine-induced catecholamine release increases sensitivity to the effects of direct acting sympathomimetics. CLINICAL EFFECTS: Increased effects of direct acting sympathomimetics. Decreased effects of indirect acting sympathomimetics. Mixed acting sympathomimetics will show effects based on the predominance of either direct or indirect activity. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: If these agents are administered concurrently, monitor blood pressure. The dose of the sympathomimetic may need to be adjusted. DISCUSSION: This interaction has been well documented in animal studies and human case reports have confirmed the interaction. Reserpine has been shown to decrease the response to epinephrine administered for hypotension. Reserpine has also been shown to decrease the effectiveness of ophthalmic epinephrine, a direct acting sympathomimetic. Ophthalmic phenylephrine has been shown to decrease the hypotensive effects of reserpine.	RESERPINE
Sympathomimetics (Direct, Mixed-Acting)/Methyldopa SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Unknown. CLINICAL EFFECTS: The pressor response to sympathomimetics may be increased. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Start with low doses of sympathomimetics and monitor blood pressure of patients during concurrent administration of sympathomimetics and methyldopa. DISCUSSION: The pressor response to sympathomimetics has been reported to be increased during methyldopa administration. In addition to increased duration of pressor response, severe hypertension has been reported.	METHYLDOPA, METHYLDOPA-HYDROCHLOROTHIAZIDE, METHYLDOPATE HCL
Codeine/Strong CYP2D6 Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Strong inhibitors of CYP2D6 may inhibit the metabolism of codeine to its active form, morphine. CLINICAL EFFECTS: The concurrent administration of codeine and a strong inhibitor of CYP2D6 may result in decreased efficacy of codeine. If a strong CYP2D6 inhibitor is discontinued, the effects of codeine may be increased, including respiratory depression. PREDISPOSING FACTORS: Patients with CYP2D6 ultrarapid, normal, and intermediate metabolizer phenotypes may be affected to a greater extent by CYP2D6 inhibitors. For patients on strong CYP2D6 inhibitors, the predicted phenotype is a CYP2D6 poor metabolizer. Patients who are CYP2D6 poor metabolizers lack CYP2D6 function and are not affected by CYP2D6 inhibition. PATIENT MANAGEMENT: Patients receiving concurrent therapy with codeine and a strong CYP2D6 inhibitor should be observed for decreased effectiveness of codeine. Dose increase of codeine may be required, or an alternative analgesic, such as morphine, may need to be considered. After discontinuation of a CYP2D6 inhibitor, consider reducing the dosage of codeine and monitor the patient for signs and symptoms of respiratory depression or sedation. DISCUSSION: Strong inhibitors of CYP2D6 have been shown to decrease the metabolism of codeine to morphine at CYP2D6. Quinidine has also been shown to decrease cerebrospinal fluid levels of morphine after codeine administration. Concurrent administration resulted in decreased effects of codeine. Strong CYP2D6 inhibitors linked to this monograph are: bupropion, dacomitinib, fluoxetine, hydroquinidine, paroxetine, quinidine and terbinafine.	APLENZIN, AUVELITY, BUPROPION HCL, BUPROPION HCL SR, BUPROPION XL, CONTRAVE, FLUOXETINE DR, FLUOXETINE HCL, FORFIVO XL, NUEDEXTA, OLANZAPINE-FLUOXETINE HCL, PAROXETINE CR, PAROXETINE ER, PAROXETINE HCL, PAROXETINE MESYLATE, PAXIL, PAXIL CR, PROZAC, QUINIDINE GLUCONATE, QUINIDINE SULFATE, TERBINAFINE HCL, VIZIMPRO, WELLBUTRIN SR, WELLBUTRIN XL
Opioids/Buprenorphine; Pentazocine SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Buprenorphine is a partial agonist at mu-opiate receptors, exhibiting a ceiling effect at which higher doses produce no further effect. Pentazocine is a mixed agonist-antagonist at opiate receptors.(1) Full mu-opioid agonists (e.g., morphine, methadone) continue to have increased effects at higher doses without ceiling effects.(2) CLINICAL EFFECTS: Concurrent use of buprenorphine or pentazocine with other opioids in opioid dependent patients may result in withdrawal symptoms. Concurrent use in other patients may result in additive or decreased analgesia and decreased opioid side effects. PREDISPOSING FACTORS: Patients dependent on opioids or who take higher dosages of opioids may be more likely to experience withdrawal symptoms with concurrent use. PATIENT MANAGEMENT: Use buprenorphine and pentazocine with caution in patients maintained or dependent on other opioids and monitor for signs of withdrawal. In other patients, also monitor for changes in analgesic effects. The manufacturer of Sublocade states buprenorphine may precipitate opioid withdrawal in patients who are currently physically dependent on full opioid agonists. The risk of withdrawal may be increased if buprenorphine is given less than 6 hours after short-acting opioids (such as heroin, morphine) and less than 24 hours after long-acting opioids (such as methadone).(3) DISCUSSION: Concurrent use of buprenorphine with other opioids in opioid dependent patients could result in withdrawal symptoms. Concurrent use in other patients may result in additive or decreased analgesia, decreased opioid side effects, and/or renarcotization.(2) In clinical trials, administration of buprenorphine injection produced withdrawal symptoms in patients maintained on methadone (30 mg daily) when administered 2 hours post-methadone,(4) but not when administered 20 hours post-methadone.(5) In another study, sublingual buprenorphine produced withdrawal symptoms in patients maintained on methadone. Symptoms were more pronounced in patients maintained on 60 mg daily doses than in patients maintained on 30 mg daily doses.(6) In a study of 10 patients maintained on methadone (100 mg daily), only three were able to tolerate escalating sublingual doses of buprenorphine/naloxone up to 32/8 mg. Split doses produced less withdrawal symptoms than full doses.(7) In a case report, a heroin-user maintained in a buprenorphine-maintenance program began stockpiling his buprenorphine instead of ingesting it and began using heroin. He then decided to re-initiate treatment on his own and ingested between 80 and 88 mg of buprenorphine over a two day period and experienced extreme withdrawal symptoms, despite restarting heroin during these symptoms. Methadone relieved his withdrawal symptoms.(8)	BELBUCA, BRIXADI, BUPRENORPHINE, BUPRENORPHINE HCL, BUPRENORPHINE-NALOXONE, BUTRANS, PENTAZOCINE-NALOXONE HCL, SUBLOCADE, SUBOXONE, ZUBSOLV
Opioids/Butorphanol SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Butorphanol antagonize mu-opiate receptors. Other opioids agonize mu-opiate receptors.(1) CLINICAL EFFECTS: Concurrent use of butorphanol with other opioids in opioid dependent patients may result in withdrawal symptoms. Concurrent use in other patients may result in additive or decreased analgesia and decreased opioid side effects. PREDISPOSING FACTORS: Patients dependent on opioids may be more likely to experience withdrawal symptoms with concurrent use. Patients using higher doses of opioids may also be at a higher risk. PATIENT MANAGEMENT: Use butorphanol with caution in patients maintained or dependent on other opioids and monitor for signs of withdrawal. In other patients, also monitor for changes in analgesic effects. DISCUSSION: Because butorphanol antagonizes mu-opiate receptors and other opioids agonize mu-opiate receptors, concurrent use of buprenorphine with other opioids in opioid dependent patients may result in withdrawal symptoms. Concurrent use in other patients may result in additive or decreased analgesia and decreased opioid side effects.(1) In a study in patients maintained on methadone, butorphanol produced withdrawal symptoms comparable to naloxone.(2) In a case report, the use of remifentanil for conscious sedation in a patient maintained on butorphanol produced severe withdrawal symptoms.(3)	BUTORPHANOL TARTRATE
Opioids/Nalbuphine SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Nalbuphine(1) antagonizes mu-opiate receptors. Other opioids agonize mu-opiate receptors. CLINICAL EFFECTS: Concurrent use of nalbuphine with other opioids in opioid dependent patients may result in withdrawal symptoms. Concurrent use in other patients may result in additive or decreased analgesia, decreased opioid side effects, and/or renarcotization. PREDISPOSING FACTORS: Patients dependent on opioids may be more likely to experience withdrawal symptoms with concurrent use. In opioid naive patients, higher doses of nalbuphine may result in decreased analgesic effects. PATIENT MANAGEMENT: Use nalbuphine with caution in patients maintained or dependent on other opioids and monitor for signs of withdrawal. In other patients, also monitor for changes in analgesic effects. If nalbuphine is used to reverse opioid anesthesia, monitor patients for renarcotization. DISCUSSION: Nalbuphine has been successfully used as an adjunct to morphine without decreasing analgesic effects.(2,3) However, other studies reported increased morphine requirements in patients who had initially received nalbuphine.(4,5) Nalbuphine has been used to reverse fentanyl anesthesia;(8-13) however, patients often required additional pain medication(5-7) and some studies reported renarcotization after the effects of nalbuphine wore off.(9,10) Nalbuphine has also been used to prevent epidural fentanyl,(13) morphine(14-16), and hydromorphone induced pruritus;(17-18) however, one study reported shortening of the duration of analgesia(16) and another reported increased PCA demands.(17) In methadone-dependent subjects, administration of nalbuphine produced withdrawal symptoms similar to naloxone.(19,20) Administration of nalbuphine to patients maintained on controlled-release morphine resulted in withdrawal symptoms.(20,21)	NALBUPHINE HCL
Desmopressin/Agents with Hyponatremia Risk SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Carbamazepine, chlorpromazine, lamotrigine, NSAIDs, opioids, SSRIs, thiazide diuretics, and/or tricyclic antidepressants increase the risk of hyponatremia.(1-3) CLINICAL EFFECTS: Concurrent use may increase the risk of hyponatremia with desmopressin.(1-3) PREDISPOSING FACTORS: Predisposing factors for hyponatremia include: polydipsia, renal impairment (eGFR < 50 ml/min/1.73m2), illnesses that can cause fluid/electrolyte imbalances, age >=65, medications that cause water retention and/or increase the risk of hyponatremia (glucocorticoids, loop diuretics). PATIENT MANAGEMENT: The concurrent use of agents with a risk of hyponatremia with desmopressin may increase the risk of hyponatremia. If concurrent use is deemed medically necessary, make sure serum sodium levels are normal before beginning therapy and consider using the desmopressin nasal 0.83 mcg dose. Consider measuring serum sodium levels more frequently than the recommended intervals of: within 7 days of concurrent therapy initiation, one month after concurrent therapy initiation and periodically during treatment. Counsel patients to report symptoms of hyponatremia, which may include: headache, nausea/vomiting, feeling restless, fatigue, drowsiness, dizziness, muscle cramps, changes in mental state (confusion, decreased awareness/alertness), seizures, coma, and trouble breathing. Counsel patients to limit the amount of fluids they drink in the evening and night-time and to stop taking desmopressin if they develop a stomach/intestinal virus with nausea/vomiting or any nose problems (blockage, stuffy/runny nose, drainage).(1) DISCUSSION: In clinical trials of desmopressin for the treatment of nocturia, 4 of 5 patients who developed severe hyponatremia (serum sodium <= 125 mmol/L) were taking systemic or inhaled glucocorticoids. Three of these patients were also taking NSAIDs and one was receiving a thiazide diuretic.(2) Drugs associated with hyponatremia may increase the risk, including loop diuretics, carbamazepine, chlorpromazine, glucocorticoids, lamotrigine, NSAIDs, opioids, SSRIs, thiazide diuretics, and/or tricyclic antidepressants.(1,3-4)	DDAVP, DESMOPRESSIN ACETATE, NOCDURNA
Opioids (Cough & Cold)/Selected Stimulants SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Opioids and stimulants exhibit opposing effects on the CNS. CLINICAL EFFECTS: Concurrent use of opioids and stimulants may have unpredictable effects and may mask overdose symptoms of the opioid, such as drowsiness and inability to focus. PREDISPOSING FACTORS: Concurrent use of alcohol or other CNS depressants may increase the risk of adverse effects. PATIENT MANAGEMENT: Limit prescribing opioid analgesics with CNS stimulants such as amphetamines to patients for whom alternatives are inadequate. If concurrent use is necessary, limit the dosages and duration of each drug to the minimum possible while achieving the desired clinical effect. Respiratory depression can occur at any time during opioid therapy, especially during therapy initiation and following dosage increases. Consider this risk when using concurrently with stimulants.(1) Monitor patients receiving concurrent therapy for signs of substance abuse. DISCUSSION: A total of 70,237 persons died from drug overdoses in the United States in 2017; approximately two thirds of these deaths involved an opioid.(2). The CDC analyzed 2016-2017 changes in age-adjusted death rates involving cocaine and psychostimulants by demographic characteristics, urbanization levels, U.S. Census region, 34 states, and the District of Columbia (DC). The CDC also examined trends in age-adjusted cocaine-involved and psychostimulant-involved death rates from 2003 to 2017 overall, as well as with and without co-involvement of opioids. Among all 2017 drug overdose deaths, 13,942 (19.8%) involved cocaine, and 10,333 (14.7%) involved psychostimulants. Death rates increased from 2016 to 2017 for both drug categories across demographic characteristics, urbanization levels, Census regions, and states. In 2017, opioids were involved in 72.7% and 50.4% of cocaine-involved and psychostimulant-involved overdoses, respectively, and the data suggest that increases in cocaine-involved overdose deaths from 2012 to 2017 were driven primarily by synthetic opioids.(3) There was opioid co-involvement in 72.7 percent of cocaine and 50.4 percent of stimulant-involved overdose deaths. This was largely driven by synthetic opioids such as fentanyl. However, stimulant-involved overdose without opioid co-involvement is also increasing.(2)	ADDERALL, ADDERALL XR, ADZENYS XR-ODT, AMPHETAMINE SULFATE, APTENSIO XR, AZSTARYS, CONCERTA, COTEMPLA XR-ODT, DAYTRANA, DESOXYN, DEXEDRINE, DEXMETHYLPHENIDATE HCL, DEXMETHYLPHENIDATE HCL ER, DEXTROAMPHETAMINE SULFATE, DEXTROAMPHETAMINE SULFATE ER, DEXTROAMPHETAMINE-AMPHET ER, DEXTROAMPHETAMINE-AMPHETAMINE, DYANAVEL XR, EVEKEO, FOCALIN, FOCALIN XR, JORNAY PM, LISDEXAMFETAMINE DIMESYLATE, METADATE CD, METADATE ER, METHAMPHETAMINE HCL, METHYLIN, METHYLPHENIDATE, METHYLPHENIDATE ER, METHYLPHENIDATE ER (LA), METHYLPHENIDATE HCL, METHYLPHENIDATE HCL CD, METHYLPHENIDATE HCL ER (CD), MYDAYIS, PROCENTRA, QUILLICHEW ER, QUILLIVANT XR, RELEXXII, RITALIN, RITALIN LA, VYVANSE, XELSTRYM, ZENZEDI
Zonisamide/Anticholinergics SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Zonisamide can cause decreased sweating and elevated body temperature. Agents with anticholinergic activity can predispose patients to heat-related disorders.(1-2) CLINICAL EFFECTS: Concurrent use of zonisamide with agents with anticholinergic activity may increase the incidence of oligohidrosis and hyperthermia, especially in pediatric or adolescent patients.(1-2) Overheating and dehydration can lead to brain damage and death. PREDISPOSING FACTORS: Pediatric and adolescent patients and patients with dehydration may be more likely to experience heat-related disorders.(1) PATIENT MANAGEMENT: The UK and US manufacturers of zonisamide state that caution should be used in adults when zonisamide is prescribed with other medicinal products that predispose to heat-related disorders, such as agents with anticholinergic activity.(1-2) Pediatric and adolescent patients must not take anticholinergic agents (e.g. clomipramine, hydroxyzine, diphenhydramine, haloperidol, imipramine, and oxybutynin) concurrently with zonisamide.(1) Monitor for signs and symptoms of heat stroke: skin feels very hot with little or no sweating, confusion, muscle cramps, rapid heartbeat, or rapid breathing. Monitor for signs and symptoms of dehydration: dry mouth, urinating less than usual, dark-colored urine, dry skin, feeling tired, dizziness, or irritability. If signs or symptoms of dehydration, oligohidrosis, or elevated body temperature occur, discontinuation of zonisamide should be considered. DISCUSSION: Case reports of decreased sweating and elevated temperature have been reported, especially in pediatric patients. Some cases resulted in heat stroke that required hospital treatment and resulted in death.(1)	ZONEGRAN, ZONISADE, ZONISAMIDE
Topiramate/Anticholinergics SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Topiramate can cause decreased sweating and elevated body temperature. Agents with anticholinergic activity can predispose patients to heat-related disorders.(1-2) CLINICAL EFFECTS: Concurrent use of topiramate with agents with anticholinergic activity may increase the incidence of oligohidrosis and hyperthermia, especially in pediatric or adolescent patients.(1-2) Overheating and dehydration can lead to brain damage and death. PREDISPOSING FACTORS: Pediatric and adolescent patients and patients with dehydration may be more likely to experience heat-related disorders.(1) PATIENT MANAGEMENT: The manufacturer of topiramate states that caution should be used when topiramate is prescribed with other medicinal products that predispose to heat-related disorders, such as agents with anticholinergic activity (e.g. clomipramine, hydroxyzine, diphenhydramine, haloperidol, imipramine, and oxybutynin) concurrently with zonisamide.(1) Monitor for signs and symptoms of heat stroke: skin feels very hot with little or no sweating, confusion, muscle cramps, rapid heartbeat, or rapid breathing. Monitor for signs and symptoms of dehydration: dry mouth, urinating less than usual, dark-colored urine, dry skin, feeling tired, dizziness, or irritability. If signs or symptoms of dehydration, oligohidrosis, or elevated body temperature occur, discontinuation of zonisamide should be considered. DISCUSSION: Case reports of decreased sweating and elevated temperature have been reported, especially in pediatric patients. Some cases resulted in heat stroke that required hospital treatment.(1) A 64-year old woman developed non-exertional hyperthemia while taking multiple psychiatric medications with topiramate.(2)	EPRONTIA, PHENTERMINE-TOPIRAMATE ER, QSYMIA, TOPAMAX, TOPIRAMATE, TOPIRAMATE ER, TOPIRAMATE ER SPRINKLE, TROKENDI XR

The following contraindication information is available for MAXI-TUSS CD (chlorpheniramine maleate/phenylephrine hcl/codeine phosphate):

Overview
Contraindicated
Severe
Moderate

Drug contraindication overview.

No enhanced Contraindications information available for this drug.

There are 4 contraindications. Absolute contraindication.

Contraindication List
Acute asthma attack
Adenoidectomy in pediatric patient
Severe uncontrolled hypertension
Tonsillectomy in pediatric patient

There are 24 severe contraindications. Adequate patient monitoring is recommended for safer drug use.

Severe List
Acute pancreatitis
Angle-closure glaucoma
Benign prostatic hyperplasia
Bladder outflow obstruction
Chronic idiopathic constipation
Chronic kidney disease stage 5 (failure) GFr<15 ml/min
Coronary artery disease
CYp2d6 poor metabolizer
CYp2d6 ultrarapid metabolizer
Drug abuse
Exacerbation of chronic obstructive pulmonary disease
Familial dysautonomia
Gastrointestinal obstruction
History of opioid overdose
Hypertension
Hyperthyroidism
Intracranial hypertension
Kidney disease with likely reduction in glomerular filtration rate (GFr)
Respiratory depression
Shock
Sleep apnea
Stenosing peptic ulcer
Systemic mastocytosis
Urinary retention

There are 15 moderate contraindications. Clinically significant contraindication, where the condition can be managed or treated before the drug may be given safely.

Moderate List
Adrenocortical insufficiency
Alcohol intoxication
Biliary tract disorder
Chronic heart failure
Chronic obstructive pulmonary disease
Constipation
Cor pulmonale
Debilitation
Hypertension
Hyperthyroidism
Hypotension
Seizure disorder
Severe hepatic disease
Untreated hypothyroidism
Urinary retention

The following adverse reaction information is available for MAXI-TUSS CD (chlorpheniramine maleate/phenylephrine hcl/codeine phosphate):

Overview
Severe
Less Severe

Adverse reaction overview.

No enhanced Common Adverse Effects information available for this drug.

There are 35 severe adverse reactions.

More Frequent	Less Frequent
None.	Atelectasis CNS depression Dyspnea Hypotension Orthostatic hypotension Respiratory depression

Rare/Very Rare
Accidental fall Acute respiratory failure Adrenocortical insufficiency Anaphylaxis Androgen deficiency Blood dyscrasias Bradycardia Cardiac arrest Cardiac arrhythmia Dizziness Drug dependence Extrasystoles Hallucinations Headache disorder Hemolytic anemia Hyperhidrosis Hypersensitivity drug reaction Hypotension Ileus Insomnia Nervousness Opioid dependence Pallor Pancreatitis Seizure disorder Shock Sleep apnea Tachycardia Tremor

Rare/Very Rare

Accidental fall
Acute respiratory failure
Adrenocortical insufficiency
Anaphylaxis
Androgen deficiency
Blood dyscrasias
Bradycardia
Cardiac arrest
Cardiac arrhythmia
Dizziness
Drug dependence
Extrasystoles
Hallucinations
Headache disorder
Hemolytic anemia
Hyperhidrosis
Hypersensitivity drug reaction
Hypotension
Ileus
Insomnia
Nervousness
Opioid dependence
Pallor
Pancreatitis
Seizure disorder
Shock
Sleep apnea
Tachycardia
Tremor

There are 83 less severe adverse reactions.

More Frequent	Less Frequent
Abdominal pain with cramps Anticholinergic toxicity Constipation Dizziness Drowsy Hyperhidrosis Nausea Sedation Thick bronchial secretions Vomiting	Acute cognitive impairment Anorexia Dizziness Dysphoric mood General weakness Headache disorder Muscle weakness Nervousness Oliguria Palpitations Pruritus of skin Sedation Skin rash Syncope Urticaria Visual changes Xerostomia

Rare/Very Rare
Abdominal distension Accidental fall Acute abdominal pain Acute cognitive impairment Agitation Anorexia Ataxia Biliary spasm Blurred vision Chest discomfort Chills Constipation Depression Diarrhea Diplopia Dry nose Dry throat Dyspnea Dysuria Erectile dysfunction Euphoria Excitement Fatigue Flushing Gastrointestinal irritation Headache disorder Hyperhidrosis Infertility Insomnia Irritability Libido changes Maculopapular rash Malaise Migraine Nausea Nervousness Nightmares Opioid induced allodynia Opioid induced hyperalgesia Palpitations Paresthesia Pruritus of skin Skin photosensitivity Skin rash Symptoms of anxiety Tachycardia Tinnitus Tremor Urinary retention Urticaria Vasodilation of blood vessels Vertigo Visual changes Vomiting Wheezing Xerostomia

Rare/Very Rare

Abdominal distension
Accidental fall
Acute abdominal pain
Acute cognitive impairment
Agitation
Anorexia
Ataxia
Biliary spasm
Blurred vision
Chest discomfort
Chills
Constipation
Depression
Diarrhea
Diplopia
Dry nose
Dry throat
Dyspnea
Dysuria
Erectile dysfunction
Euphoria
Excitement
Fatigue
Flushing
Gastrointestinal irritation
Headache disorder
Hyperhidrosis
Infertility
Insomnia
Irritability
Libido changes
Maculopapular rash
Malaise
Migraine
Nausea
Nervousness
Nightmares
Opioid induced allodynia
Opioid induced hyperalgesia
Palpitations
Paresthesia
Pruritus of skin
Skin photosensitivity
Skin rash
Symptoms of anxiety
Tachycardia
Tinnitus
Tremor
Urinary retention
Urticaria
Vasodilation of blood vessels
Vertigo
Visual changes
Vomiting
Wheezing
Xerostomia

The following precautions are available for MAXI-TUSS CD (chlorpheniramine maleate/phenylephrine hcl/codeine phosphate):

Pediatric
Pregnant
Lactation
Geriatric

No enhanced Pediatric Use information available for this drug.

Contraindicated

None

Severe Precaution

None

Management or Monitoring Precaution

None

Reproduction studies in animals using dexchlorpheniramine have not been performed to date, but reproduction studies in rabbits and rats using chlorpheniramine maleate dosages up to 50 and 85 times the usual human dosage, respectively, have not revealed evidence of harm to the fetus. Decreased postnatal survival in offspring of rats receiving 33 and 67 times the usual human dosage of chlorpheniramine maleate has been reported. There are no adequate and controlled studies to date using chlorpheniramine or dexchlorpheniramine in pregnant women, and the drugs should be used during the first 2 trimesters only when clearly needed.

In one epidemiologic study, use of chlorpheniramine was not associated with an increased risk of teratogenic effects; however, only a limited number of pregnant women received the drug in this study. Because of the risk of severe reactions (e.g., seizures) to antihistamines in neonates, chlorpheniramine or dexchlorpheniramine should not be used during the third trimester. It is not known whether phenylephrine hydrochloride can cause fetal harm when administered to pregnant women; the drug should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Animal studies suggest a potential for adverse cardiovascular effects to the fetus if the drug is administered IV during pregnancy. Administration of phenylephrine to patients in late pregnancy or labor may cause fetal anoxia and bradycardia by increasing contractility of the uterus and decreasing uterine blood flow. In studies of IV phenylephrine in pregnant women undergoing cesarean delivery with neuraxial anesthesia, common adverse effects reported in the mother included nausea and vomiting, bradycardia, reactive hypertension, and transient arrhythmias.

The drug did not appear to affect neonatal Apgar scores or umbilical artery blood-gas status. If a vasopressor is used in conjunction with oxytocic drugs, the vasopressor effect is potentiated and may result in potentially serious adverse effects. (See Drug Interactions: Oxytocic Drugs.)

It is not known whether chlorpheniramine or dexchlorpheniramine is distributed into milk, but other antihistamines (e.g., diphenhydramine) have been detected in milk. Because of the potential for serious adverse reactions to antihistamines in nursing infants, a decision should be made whether to discontinue nursing or chlorpheniramine or dexchlorpheniramine, taking into account the importance of the drug to the woman. It is not known whether phenylephrine is distributed into human milk following parenteral administration. The drug should be used with caution in nursing women.

No enhanced Geriatric Use information available for this drug.

The following prioritized warning is available for MAXI-TUSS CD (chlorpheniramine maleate/phenylephrine hcl/codeine phosphate):

WARNING: This medication has a risk for abuse and addiction, which can lead to overdose and death. This medication may also cause severe, possibly fatal, breathing problems. To lower your risk, your doctor should have you take the smallest dose that works, and take it for the shortest possible time.

See also How to Use section for more information about addiction. The risk for severe breathing problems is higher when you start this medication, or if you take the wrong dose or take more of this medication than prescribed. Taking this medication with alcohol or other drugs that can cause drowsiness or breathing problems may cause very serious side effects, including death.

Also, other medications can affect the removal of this product from your body, which may affect how it works. Be sure you know how to take this product and what other drugs you should avoid taking with it. See also Drug Interactions section.

Get medical help right away if any of these very serious side effects occur: slow/shallow breathing, unusual lightheadedness, severe drowsiness/dizziness, difficulty waking up. Keep this medicine in a safe place to prevent theft, misuse, or abuse. If someone accidentally swallows this drug, get medical help right away.

Before using this medication, women of childbearing age should talk with their doctor(s) about the risks and benefits. Tell your doctor if you are pregnant or think you may be pregnant. During pregnancy, this medication is not recommended.

It may slightly increase the risk of birth defects if used during the first two months of pregnancy. Also, using it for a long time or in high doses near the expected delivery date may harm the unborn baby. To lessen the risk, take the smallest effective dose for the shortest possible time.

Babies born to mothers who use this drug for a long time may develop severe (possibly fatal) withdrawal symptoms. Tell the doctor right away if you notice any symptoms in your newborn baby such as crying that doesn't stop, slow/shallow breathing, irritability, shaking, vomiting, diarrhea, poor feeding, or difficulty gaining weight.

The following icd codes are available for MAXI-TUSS CD (chlorpheniramine maleate/phenylephrine hcl/codeine phosphate)'s list of indications:

Allergic rhinitis
J30.1	Allergic rhinitis due to pollen
J30.2	Other seasonal allergic rhinitis
J30.5	Allergic rhinitis due to food
J30.8	Other allergic rhinitis
J30.81	Allergic rhinitis due to animal (cat) (dog) hair and dander
J30.89	Other allergic rhinitis
J30.9	Allergic rhinitis, unspecified
Cold symptoms
J00	Acute nasopharyngitis [common cold]
Cough
R05	Cough
R05.1	Acute cough
R05.2	Subacute cough
R05.3	Chronic cough
R05.9	Cough, unspecified
Nasal congestion
R09.81	Nasal congestion
Rhinorrhea
R09.82	Postnasal drip