Double-blind trial to compare ampicillin, cephalexin, co-trimoxazole, and trimethoprim in treatment of urinary infection.

In order to test their value in urinary infection a double-blind trial was carried out using ampicillin, cephalexin, trimethoprim-sulphamethoxazole (co-trimoxazole), and trimethoprim. Eighty-three courses of treatment were given to hospital patients, 149 to pregnant women, and 107 to patients with dysuria and frequency seen in domiciliary practice. Thus infections of varying severity in defined groups of patients caused by organisms with different antibiotic sensitivities were treated.Analysis of the overall results (339 courses) was compared with those from the individual groups and considerable variation in response was found. In domiciliary infections and bacteriuria in pregnancy trimethoprim alone proved to be at least as effective as the other three compounds and caused fewer than half the number of side effects. In the hospital patients co-trimoxazole was superior to trimethoprim.The overall results for ampicillin and cephalexin were similar although cephalexin proved to be inferior in treating symptomatic domiciliary infections.