Efficacy of daily silodosin 8 mg as a potential reversible male contraceptive: A prospective placebo controlled study.

OBJECTIVE

To assess the efficacy of silodosin 8 mg as potentially reversible male contraceptive.

METHODS

In all, 200 healthy, sexually active, fertile male candidates were assigned as follows: 100 in silodosin group and 100 in placebo group. Males using other contraceptive methods were excluded. Follow up data of total spermatozoa per ejaculate, semen volume and post-ejaculation urinalysis after 2, 6 and 12 weeks of the studied groups were recorded. The various side effects reported in the study groups after 12 weeks from the start of the study were recorded.

MAIN OUTCOME MEASURES: The primary outcome measure was the treatment period and pregnancy rate during the study to evaluate silodosin contraceptive efficacy. The secondary outcome measure was intolerance to the drug due to adverse events leading to dropping out of the study.

RESULTS

After 3 months, total spermatozoa per ejaculate and semen volume in silodosin group were 0.113 ± 0.480 (0.0003-3.1) and 0.600 ± 0.028 (0.55-0.64) respectively that were highly significantly decreased compared to placebo group 75.967 ± 5.105 (66.4-85.90) and 2.415 ± 0.278 (1.99-3.03) respectively, p < 0.001. Side effects in the study groups after 3 months, silodosin group significantly suffered from stuffy nose, dizziness, weakness and scanty ejaculate (26%, 17%, 15% and 84%, respectively) higher than placebo group (4%, 2%, 4% and 6%, respectively), with highly significant difference between groups, p < 0.001, < 0.001, 0.008 and < 0.001, respectively). Silodosin group significantly had lower pregnancy incidence (4%) compared to placebo group (17%), p < 0.001.

CONCLUSION

Silodosin 8 mg yields a better sperm suppression results as on-demand male contraception after 3 months of continuous daily oral intake when compared to placebo, associated with pregnancy rate of 4% and higher but tolerable side effects.