Pyrimethamine: an approach to the development of a male contraceptive.

With the human population of the world currently more than 5.2 billion and growing at an explosive rate, the need for additional forms of readily available contraception appears paramount. To date, contraception techniques in the male have been very limited. The present study demonstrates the ability of pyrimethamine (PYR) to cause spermatogenic arrest and male infertility in mice in a dose-dependent manner. Furthermore, upon cessation of drug administration all animals returned to normal fertility status. It is also suggested that the action of PYR is due to its antifolate action. Thus, PYR represents another approach toward development of a male contraceptive.