The effect of drugs on male sexual function and fertility.

Drugs may have negative effects on male libido, erection, ejaculation and orgasm, as well as on fertility, and research on these effects is increasing. Libido may be decreased by drugs that block dopamine or testosterone, or that cause dysphoria. Erection may be decreased by drugs that divert blood flow from the penis, or drugs that affect spinal reflexes. Ganglion blockers may also inhibit erection. Ejaculation may be diminished by drugs that affect spinal reflexes or be inhibited by ganglion blockage. Enervation of the vas deferens and epididymis may be blocked and cause a smaller emission. Retrograde ejaculation may occur due to blockage of the internal urethral sphincter. Orgasm is usually inhibited by the drugs that inhibit ejaculation. Fertility is impaired by drugs that affect sexual performance or spermatogenesis. Major groups of drugs that may affect male sexual function include drugs of abuse, CNS depressants, antihypertensives, anticholinergics, psychotherapeutics, hormones, and cancer therapeutics, in addition to miscellaneous other agents. Information about these drugs has been arranged in tables so that the provider has a convenient reference to use when explaining to men the effect of drugs on sexual response and fertility.