Interaction Checker

Methenamine interactions

Methenamine (Hiprex, Urex), an antibiotic has 5 documented interactions across the FDA labels and fact sheets we index: 0 major, 4 moderate, 1 minor, and 0 where a label reports no significant interaction. Each entry below quotes the sentence behind it. This drug page is a starting point, not a verdict for your situation.

Interactions from the label

Moderate interactions (4)

  • DextroamphetamineCNS stimulantModerate

    Methenamine Therapy Urinary excretion of amphetamines is increased, and efficacy is reduced, by acidifying agents used in methenamine therapy. (Dextroamphetamine label, Drug interactions)

  • Fosinopril and hydrochlorothiazideACE inhibitorModerate

    By alkalinizing the urine, hydrochlorothiazide may decrease the effectiveness of methenamine. (Fosinopril and hydrochlorothiazide label, Drug interactions)

  • Metolazonethiazide diureticModerate

    Methenamine Efficacy may be decreased due to urinary alkalizing effect of metolazone. (Metolazone label, Drug interactions)

  • Triamterene and hydrochlorothiazidepotassium-sparing diureticModerate

    The effectiveness of methenamine may be decreased when used concurrently with hydrochlorothiazide because of alkalinization of the urine. (Triamterene and hydrochlorothiazide label, Drug interactions)

Minor mentions (1)

  • Acetazolamidecarbonic anhydrase inhibitorMinor

    Acetazolamide may prevent the urinary antiseptic effect of methenamine. (Acetazolamide label, Drug interactions)

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Not medical advice. Severity reflects the label's wording, not your circumstances. A "major" flag can be routine under supervision and a "minor" one can matter at high doses. Ask a pharmacist.