Methenamine Disease Interactions

There are 2 disease interactions with methenamine:

The use of methenamine salts (i.e. methenamine hippurate or mandelate), but not the base, is contraindicated in patients with severe renal impairment or dehydration. Methenamine is excreted by the kidney and concentrated in the urine. In patients with low urinary output, the salts can precipitate and cause crystalluria.

The use of methenamine and its salts (i.e. methenamine hippurate or mandelate) is contraindicated in patients with severe hepatic impairment. Methenamine is hydrolyzed to ammonia and formaldehyde in the urine under acidic conditions. Patients with liver disease may already have elevated ammonia levels, which can cause or exacerbate hepatic encephalopathy. Methenamine hippurate has also been associated with isolated cases of transient elevations in serum transaminases. The manufacturer recommends periodic liver function tests during therapy, particularly in patients with preexisting liver dysfunction.

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methenamine drug Interactions

There are 118 drug interactions with methenamine

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