Phenoxybenzamine--an effective male contraceptive pill.

Phenoxybenzamine (PBZ), administered in doses up to 20 mg/day, caused aspermia following male orgasm. This led to the development of a male contraceptive pill, PBZ being the active drug. It has been shown that small doses of the drug do not change the hormonal balance of the body, nor do they affect blood pressure. In 2 to 3 days, PBZ blocks ejaculation; this is fully reversed with the cessation of treatment. The drug does not affect semen quality (testicular function), even after a long period of medication. During treatment, the vas deferens, the ampulla and the ejaculatory ducts are probably paralyzed. Cessation of medication brought full recovery of these effects and the reappearance of normal ejaculation. Men complaining of premature ejaculation reported marked improvement in their sexual performance. The recommended regimen for administering PBZ as a male contraceptive is discussed.