Infectious Disease Compendium

Methenamine

Dosing

CrCl Formula

CrCl > 80: 1 g po bid. Take with vitamin C to keep urine pH low.

CrCl 80-50:

CrCl 50-10:

CrCl < 10:

Hemodialysis:

Peritoneal dialysis:

Important side effects

Important drug interactions

Antacids, sulfamethizole.

Rants and Screeds

Pearls

Have to keep the pH < 6 to work. Urea-splitting organisms (Proteus species) will not respond as they prevent urine acidification.

Treatment of choice

Use for

UTI, both treatment and prophylaxis.

Don't use for

Class

Turns into formaldehyde in acidic urine.