Researchers conducted two multicenter trials with a new drug for minimal erectile dysfunction. The first phase was designed as a placebo-controlled, parallel group, double-blind study involving randomized doses of 40 mg or 80 mg of either oral phentolamine or placebo. In the 40 mg group, out of 152 men, 56 (37%) responded and 96 (63%) did not. With the 80 mg dose, out of 159 men, 72 (45%) responded and 87 (55%) did not. Out of 148 patients on placebo, 24 (16%) responded.

A responder was considered any man whose condition improved by one clinical dysfunction class and who had, at endpoint, mild to moderate erectile dysfunction. The second phase was a placebo-controlled, crossover design of fixed dose 40 mg oral phentolamine versus placebo. Out of 148 patients who took 40 mg of oral phentolamine, 50 (34%) responded. Out of 145 patients on placebo, 30 (21%) responded. Although they involved less than 10% of the men, side effects to the 40 mg dose included headache, facial flushing, and nasal consumptio n. The investigators concluded that the 40 mg oral phentolamine dose is a safe and effective oral medication for the treatment of mild erectile dysfunction.