New male contraceptive entering clinical trials worldwide
Contraceptive Technology Update 10(10): 142-143
1989
ISSN/ISBN: 0274-726X PMID: 12342588 Document Number: 378711
250 men are participating in a clinical trial of a reversible male testosterone contraceptive at the University of Washington in Seattle and at 9 other centers in Europe, Asia, and Australia. Clinicians inject the WHO-developed testosterone enanthate (200 mg) into these men once a week. The testosterone contraceptive instructs the pituitary gland to deactivate 2 hormones which normally maintain the testes' function resulting in a temporary stop of spermatogenesis just like the female oral contraceptive instructs the pituitary gland to suppress ovulation. Tests of 5 ejaculates in preliminary trials have indicated that 50-60% of the men experience azoospermia. Investigators are concerned with the possibility that ejaculates during normal intercourse may contain enough sperm to impregnate the partner. An investigator at the University of Washington believes this clinical trial of 250 men will determine whether this is indeed the case. The concern about contraceptive failure is the main problem with contraceptive testosterone. The minor side effects include weight gain which may be due to increased muscle mass and some sodium retention, acne, and possible reduction of libido but that has not yet occurred in the 250 men in the clinical trial. This contraceptive testosterone does not remain active for long periods of time if administered orally. Researchers are now developing a newer form of the contraceptive which will increase the intervals between administrations from 1 week to 3 months. An investigator from Seattle guesses that this male contraceptive will not be available for marketing in the US until at least 1994.