Evaluation of efficacy, safety, and reversibility of combination regimen of cyproterone acetate and testosterone buciclate in bonnet monkey.

A combination regimen of cyproterone acetate (CPA) and testosterone buciclate (TB) was evaluated for its contraceptive efficacy, safety, and reversibility in bonnet monkeys. Cyproterone acetate (5 mg in 0.2 mL of olive oil) injected daily for 180 days, in combination with 40 mg testosterone buciclate given i.m. on days 0, 60, and 120 in the monkeys of group II (n = 6) induced azoospermia in all animals by 120 days, which was maintained until day 210. By day 240 sperm concentration increased gradually and reached baseline values by day 330. When 5mg of cyproterone acetate was injected daily for a similar duration in combination with a higher dose (80 mg) of testosterone buciclate in the monkeys of group III (n = 6) on days 0, 60, and 120, uniform and consistent azoospermia could not be achieved and two animals remained oligozoospermic even after 180 days of treatment. Mean sperm concentration did not return to baseline values until the day that the study ended, i.e. day 330. In groups II and III serum testosterone levels were elevated (p <0.05) from days 9-120 except on day 150 and returned to near baseline values by day 330. Serum testosterone levels were higher in group III compared to group II. The sperm concentration and testosterone levels in control animals (group I; n = 6) showed fluctuations. Lipid profile and liver function parameters did not show significant changes in any group. The present data clearly indicate that administration of CPA and TB in proper dosage combination can provide an effective, safe, and reversible method of male contraception.