Effects of testosterone undecanoate on sexual potency and the hypothalamic-pituitary-gonadal axis of impotent males.

A double-blind comparison was made of the effects of testosterone undecanoate (TU) and placebo on sexual potency of 29 impotent men ages 45--75. The main criteria for inclusion in the study were a reduced or nonexistent capacity to have an erection during intercourse and no clinical signs of endocrinological pathology. All patients received placebo for 2 weeks. Then TU was given at a daily dose of 120 mg to 13 patients selected at random while the other patients continued to receive placebo. After 8 weeks all patients received placebo again for 2 weeks. An improvement in sexual potency was reported by five patients given TU and eight patients given placebo, with no significant differences between the groups. Treatment with TU influenced neither the hypothalamic-pituitary-gonadal axis, as judged by levels of prolactin, LH, FSH, and the LHRH-induced LH/FSH response, nor depression, anxiety, and somatic scores or performance tests. The only specific effect of TU treatment was to decrease the total plasma testosterone level. The present findings show pharmacotherapy with androgens to be no more effective than placebo in restoring sexual potency to sexually impotent men without androgen deficiency. Further studies may be needed to elucidate fully the effects of androgen administration on psychological and endocrinological variables in such patients.