One-dose treatment of acute uncomplicated gonorrhoea of male patients with ceftriaxone Ro 13-9904, a new parenteral cephalosporin. A dose-range finding pilot study using doses of 500, 250, 125 and 50 mg respectively, in descending order.

54 adult male patients suffering from acute uncomplicated gonococcal urethritis entered a dose-range trial with a new parenteral cephalosporin, ceftriaxone Ro 13-9904. In order to evaluate the lowest effective dose of a single intramuscular injection of Ro 13-9904, the patients received different doses in descending order: 500 mg for the first group of 10 patients, 250 mg for the second group of 13 patients, 125 mg for the third group of 11 patients and 50 mg for the fourth group of 20 patients. All 34 patients of the first three trial groups were cured clinically and bacteriologically. In the group receiving 50 mg of the cephalosporin, 1 patient was bacteriologically a failure and a second was considered to be a reinfection. 7 further patients of this trial group showed clinical symptoms of urethritis after therapy, but gonococci were eradicated. The systemic and local tolerance of the drug was satisfactory. On the basis of this trial, the lowest effective dose for the eradication of Neisseria gonorrhoeae in male patients with uncomplicated gonorrhoea seems to be a single injection of between 50 and 125 mg of Ro 13-9904.