Hiprex

Drug overview for HIPREX (methenamine hippurate):

Generic name: METHENAMINE HIPPURATE (meth-EN-a-meen)
Drug class: Urinary Tract Anti-Infectives
Therapeutic class: Genitourinary Therapy

Methenamine is a synthetic urinary antibacterial agent that is chemically unrelated to other currently available anti-infectives.

No enhanced Uses information available for this drug.

DRUG IMAGES

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The following indications for HIPREX (methenamine hippurate) have been approved by the FDA:

Indications:
Prevention of bacterial urinary tract infection

Professional Synonyms:
Urinary tract infection prophylaxis
UTI prophylaxis

Generic dosing information for METHENAMINE HIPPURATE
DRUG LABEL	DOSING TYPE	DOSING INSTRUCTIONS
METHENAMINE HIPP 1 GM TABLET	Maintenance	Adults take 1 tablet (1 gram) by oral route 2 times per day

The following drug interaction information is available for HIPREX (methenamine hippurate):

Contraindicated
Severe
Moderate

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

Drug Interaction	Drug Names
Methenamine/Sulfonamides 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: Methenamine is hydrolyzed to formaldehyde in acidic urine. Sulfonamides may form an insoluble precipitate with formaldehyde in the urine.(1,2) CLINICAL EFFECTS: The concurrent administration of methenamine and sulfamethizole or sulfathiazole is likely to form a precipitate in the urine.(1-3) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Methenamine should not be administered to patients receiving sulfonamides.(1-3) DISCUSSION: Methenamine is hydrolyzed to formaldehyde in acidic urine. An in vitro study showed that addition of methenamine and mandelic acid to saturated solutions of sulfamethizole at pH 5.0 and 6.0 produced a precipitate in one hour.(4)	ACETAZOLAMIDE, ACETAZOLAMIDE ER, ACETAZOLAMIDE SODIUM, AZULFIDINE, BACTRIM, BACTRIM DS, DICHLORPHENAMIDE, KEVEYIS, METHAZOLAMIDE, ORMALVI, SULFACETAMIDE, SULFACETAMIDE SOD MONOHYDRATE, SULFACETAMIDE SODIUM, SULFADIAZINE, SULFADIAZINE SODIUM, SULFAMERAZINE, SULFAMETHOXAZOLE, SULFAMETHOXAZOLE-TRIMETHOPRIM, SULFANILAMIDE, SULFAPYRIDINE, SULFASALAZINE, SULFASALAZINE DR, SULFATHIAZOLE, SULFATRIM, SULFISOXAZOLE

Drug Interaction

Drug Names

Methenamine/Sulfonamides

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: Methenamine is hydrolyzed to formaldehyde in acidic urine. Sulfonamides may form an insoluble precipitate with formaldehyde in the urine.(1,2)

CLINICAL EFFECTS: The concurrent administration of methenamine and sulfamethizole or sulfathiazole is likely to form a precipitate in the urine.(1-3)

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: Methenamine should not be administered to patients receiving sulfonamides.(1-3)

DISCUSSION: Methenamine is hydrolyzed to formaldehyde in acidic urine. An in vitro study showed that addition of methenamine and mandelic acid to saturated solutions of sulfamethizole at pH 5.0 and 6.0 produced a precipitate in one hour.(4)

ACETAZOLAMIDE, ACETAZOLAMIDE ER, ACETAZOLAMIDE SODIUM, AZULFIDINE, BACTRIM, BACTRIM DS, DICHLORPHENAMIDE, KEVEYIS, METHAZOLAMIDE, ORMALVI, SULFACETAMIDE, SULFACETAMIDE SOD MONOHYDRATE, SULFACETAMIDE SODIUM, SULFADIAZINE, SULFADIAZINE SODIUM, SULFAMERAZINE, SULFAMETHOXAZOLE, SULFAMETHOXAZOLE-TRIMETHOPRIM, SULFANILAMIDE, SULFAPYRIDINE, SULFASALAZINE, SULFASALAZINE DR, SULFATHIAZOLE, SULFATRIM, SULFISOXAZOLE

There are 1 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
Fecal Microbiota Spores/Antibiotics SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Fecal microbiota spores is a suspension of live bacterial spores, which may be compromised by concurrent use of antibiotics.(1) CLINICAL EFFECTS: Antibiotics may decrease the effectiveness of fecal microbiota spores.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Antibiotics should not be used concurrently with fecal microbiota spores. Antibacterial treatment should be completed for 2 to 4 days before initiating treatment with fecal microbiota spores.(1) DISCUSSION: Antibiotics may compromise the effectiveness of fecal microbiota spores.	VOWST

Drug Interaction

Drug Names

Fecal Microbiota Spores/Antibiotics

SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.

MECHANISM OF ACTION: Fecal microbiota spores is a suspension of live bacterial spores, which may be compromised by concurrent use of antibiotics.(1)

CLINICAL EFFECTS: Antibiotics may decrease the effectiveness of fecal microbiota spores.(1)

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: Antibiotics should not be used concurrently with fecal microbiota spores. Antibacterial treatment should be completed for 2 to 4 days before initiating treatment with fecal microbiota spores.(1)

DISCUSSION: Antibiotics may compromise the effectiveness of fecal microbiota spores.

VOWST

There are 0 moderate interactions.

Contraindication List
Kidney disease with reduction in glomerular filtration rate (GFr)
Severe dehydration
Severe hepatic disease

Moderate List
Disease of liver

The following adverse reaction information is available for HIPREX (methenamine hippurate):

Overview
Severe
Less Severe

Adverse reaction overview.

No enhanced Common Adverse Effects information available for this drug.

There are 2 severe adverse reactions.

More Frequent	Less Frequent
None.	Skin rash

Rare/Very Rare
Hematuria

There are 4 less severe adverse reactions.

More Frequent	Less Frequent
None.	Dyspepsia Nausea

Rare/Very Rare
Dysuria Pruritus of skin

The following precautions are available for HIPREX (methenamine hippurate):

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 rats and rabbits using methenamine hippurate have not revealed evidence of harm to the fetus. A slight increase in the stillborn rate and slight impairment of weight gain and survival of live-born offspring was reported in a study in pregnant dogs using oral methenamine in dosages equivalent to the human dosage. There are no adequate and well-controlled studies to date using methenamine hippurate or methenamine mandelate in pregnant women, and the drugs should be used during pregnancy only when clearly needed.

Although safe use of methenamine or its salts during pregnancy has not been definitely established, the drugs have been used in pregnant women without adverse effects to the fetus. One manufacturer of methenamine hippurate states that safety during the last trimester is suggested, but not definitely proven. The effects of methenamine during labor and delivery are unknown and there are no recognized uses for the drug during labor or delivery.

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

No enhanced Geriatric Use information available for this drug.

Prevention of bacterial urinary tract infection
Z87.440	Personal history of urinary (tract) infections