An oral regimen of cyproterone acetate and testosterone undecanoate for spermatogenic suppression in men

Objective: To test the effectiveness, safety, and reversibility of the combined administration of cyproterone acetate and T undecanoate. Design: Open clinical trial. Setting: Healthy volunteers in an academic research environment. Patient(s): Eight healthy men, aged 25-42 years were selected. Intervention(s): Cyproterone acetate, 12.5 mg, and T undecanoate, 80 mg, were administered orally twice daily for 16 weeks. Main Outcome Measure(s): Semen analyses every 2 weeks; physical examination, chemistries, hematology, prostatic-specific antigen, gonadotropins and T levels, and a questionnaire on sexual and behavioral function every 4 weeks. Result(s): In all subjects a profound suppression of spermatogenesis occurred; one subject became azoospermic, five subjects had sperm counts of ≤3 x 106/mL, and in two subjects sperm counts were 4 and 6 x 106/mL in week 16. Sperm counts returned to baseline in all men after hormone administration was discontinued. No changes in metabolic parameters and total prostatic-specific antigen were detected. Hemoglobin and hematocrit decreased statistically significantly at week 16 of treatment and returned to baseline by week 12 of recovery. There was no change in sexual function or behavior. Conclusion(s): The oral administration of T undecanoate plus cyproterone acetate induces a profound suppression of spermatogenesis with no major adverse effects. These data suggest the feasibility of oral contraception in men.