Double-blind comparison of carbenicillin indanyl sodium, ampicillin, and cephalexin in treatment of urinary tract infection.

Carbenicillin indanyl sodium, ampicillin, or cephalexin was administered orally to 61 patients with urinary tract infections. Assignment of drug was made by a computer-generated, randomized plan in a double-blind fashion. The rates of cure 4 weeks after therapy were 50, 42, and 50% for patients treated with carbenicillin, ampicillin, and cephalexin, respectively. Failure of therapy was correlated with chronicity of infection and sensitivity of the microorganism to the antibiotic used. Thirty-nine percent of the patients developed side effects, but there were no significant differences in side effects among the three antibiotics. This double-blind study demonstrates that carbenicillin indanyl sodium is as effective as ampicillin and cephalexin in treatment of urinary tract infections.