Male contraception--a review.

Abstract

This review of male contraception provides a basis for understanding the main methods of contraception as well as which methods are more effective than others. An effective male contraceptive must be safe reversible rapid in action acceptable to the user and without adverse consequences on sexual potency or libido. There are many points along the axis of the reproductive system at which intervention could either reduce or abolish fertility; there are 2 main points at which intervention can be applied--during spermatogenesis and when spermatozoa mature. Inhibition of the normal negative feedback system may be achieved intentionally by means of administration of pharmacological amounts of these compounds; spermatogenesis would consequently be suppressed. Estrogens and progestogens are effective male contraceptives but they tend to depress the circulating testosterone which in turn produces an unacceptable reduction in libido. Other drugs that act at the hypothalamic level are: androgens anabolic steroids estrogens or progestogens with androgens medroxyprogesterone acetate/percutaneous testosterone d-Norgestrel and testosterone enanthate and levo-norgestrel and testosterone enanthate. Some drugs have been found experimentally to reduce spermatogenesis via a mechanism which bypasses the hypothalamus and anterior pituitary gland. However these compounds acting at testicular levels are often toxic to body cells in general and some may even produce genetic defects. Exmaples include: tetramine (TEM) triethylene-phosphoramide (TEPA) and gossypol. Gossypol has been claimed to be 99% effective in producing infertility within 2 to 3 months of commencing therapy; however gastrointestinal symptoms skin rashes and fatigue are undesirable side effects that have been reported. Drugs impairing sperm maturation such as chlorohydrin chlorinated sugars and antiandrogens affect the already formed and stored spermatozoa and should be able to produce infertility within as little as a few days. Drugs which are analogues of gonadotrophin releasing hormones immunological control of fertility vasectomy spermicidal agents and the sheath are 5 other types of male contraceptives discussed. Because of the side effects often associated with all types of male contraceptives whatever the future reveals it is generally agreed that it will be many years before a satisfactory male contraceptive can be available.