Combination of trimethoprim and methenamine hippurate in the treatment of acute urinary tract infections.

A new antimicrobial drug combination of trimethoprim and methenamine hippurate (TMP + MH) at 2 different dosages (100 + 500 mg and 200 + 1000 mg b.i.d.) was compared by a random double-blind technique with plain TMP (200 mg b.i.d.) and TMP-sulfamethoxazole combination (160 mg + 800 mg b.i.d.). Each of the 4 test groups of 40-47 patients with acute UTI was treated for 2 weeks. The successful response in the test groups varied from 91 to 98% and no statistical difference could be found between the groups. The side-effects were least common in the group treated with the lower dose of TMP-MH combination.