Background: Erectile dysfunction is a common medical problem affecting many men. Although several intracavernosal therapies are available, their efficacy and safety have not been studied systematically.
Methods: We investigated the efficacy and safety of alprostadil formulated for intracavernosal treatment in three separate multi-institutional, prospective studies in men with erectile dysfunction of vasculogenic, neurogenic, psychogenic, and mixed causes. Clinical and laboratory evaluations of erection and the feasibility of satisfactoriness of sexual activity as assessed both by the men and by their partners were the primary measures of efficacy.
Results: In a dose-response study of 296 men, all doses of alprostadil were superior to placebo and there was a significant dose-response relation (P < / = 0.001), resulting in higher response rates with increasing doses of alprostadil (from 2.5 to 20 microg). In a dose-finding study of 201 men, the minimal effective dose was < / = 2 microg in 23, 20, 38 and 23 percent of men with erectile dysfunction of neurogenic, vasculogenic, psychogenic, or mixed causes, respectively. In a six-month self-injection study in 683 men, the participants reported being able to have sexual activity after 94 percent of the injections. The men and their partners rated the sexual activity as satisfactory after 87 and 86 percent of the injections, respectively. Penile pain, usually mild, occurred in 50 percent of the men at some time but after only 11 percent of the injections. Prolonged erections occurred in 5 percent of the men, priapism in 1 percent, penile fibrotic complications in 2 percent, and hematoma or ecchymosis in 8 percent.
Conclusions: In men with erectile dysfunction, intracavernosal injection of alprostadil is an effective therapy with tolerable side effects.