Drugs for male contraception

In spite of the long and successful use of drugs for contraception for women, the development of drug contraceptives for men has not yet reached fruition. Complexity of the spermatogenic process, lack of understanding of many of the factors involved, sociological factors and economic concerns have played a role in this. A need now exists for new contraceptive options, including male contraceptives. Currently the only methods of choice for men are the condom and vasectomy. Because hormones play an essential role in spermatogenesis, the manipulation of hormone systems has received much study as a means of male contraception and several clinical studies have been carried out in this area. Methods that result in depletion of circulating testosterone require supplementation with this hormone or other androgenic compounds. Use of androgens alone, combinations of androgens with other steroid hormones such as progestins, and combinations of antagonists of gonadotropin releasing hormones (GnRH) with androgens have all been found to produce infertility in a significant percentage of men. Non-hormonal methods may attack the fertilisation process at any point along the pathway of spermatogenesis, transport and maturation in the epididymis and interaction with the ovum. A large variety of structures have been shown to have male antifertility effects. Many of these compounds are either natural products or substances made for another purpose, but found to cause infertility. Relatively few have been studied systematically from a medicinal chemistry standpoint, but some successes have been achieved in increasing desirable properties and diminishing side-effects. More information about the mechanism of action of these compounds is needed. Progress has also been made on the molecular biology of the spermatogenic process, with identification of targets for pharmacological intervention. It is concluded that this is a field that still needs much basic research, but that is ripe for the concerted attack of basic and applied research that pharmaceutical companies have developed and used for other drug development.

Duke Scholars

Author Chad E. Cook Orthopaedic Surgery, Physical Therapy