Therapy of gonorrhea. Comparison of trimethoprim-sulfamethoxazole and ampicillin.

Eighty-nine men with gonococcal urethritis were randomly treated with trimethoprim-sulfamethoxazole, four tablets (trimethoprin, 320 mg, and sulfamethoxazole, 1,600 mg) twice daily for two days, or ampicillin, 3.5 g, plus probenecid, 1 g, in a single dose. Forty-one (95.3%) of 43 patients who received trimethoprin-sulfamethosazole and 41 (97.6%) of 42 given ampicillin were cured. Neither drug caused major side effects. All isolates of Neisseria gonorrhoeae were susceptible in vitro to trimethoprim-sulfame-thoxazole, and all but one were inhibited by ampicillin. The ampicillin-resistant strain (minimum inhibitory concentration, 4 micrograms/ml) produced penicillinase and was reovered from a patient who responded to treatment with trimethoprim-sulfamethoxazole. There was no significant correlation between the minimum inhibitory concentrations of trimethoprim-sulfamethoxazole and ampicillin. It is concluded that trimethoprim-sulfamethoxazole is as efficacious and safe as ampicillin in the therapy of gonococcal urethritis.