Topical agents to treat erectile dysfunction are applied to the penis or perineal regions and have included hormone-derived medications, as well as vasodilators.
There are no RCT studies in this area. Topical agents that cause vasodilation, such as minoxidil, PGE1, papaverine and nitroglycerine, are generally safe yet found to be effective only in a minority of patients (providing an erection sufficient for vaginal penetration in 22-29%), most likely due to inadequate absorption through the tunica albuginia. Kim & McVary (1995), although showing a significant increase in mean cavernous artery diameter and mean peak systolic flow velocity with topical application of PGE1, reported a clinically useful erection in only 2 out of 9 subjects. One study found topical minoxidil spray to be significantly less effective than comparative treatments with papaverine ICI or a vacuum constriction device. Use of topical agents to treat ED seem to have little if any role to play in the SCI population, particularly in view of the efficacy and reliability of PDE5i and ICI.
There is level 2 evidence (from 1 non-randomized controlled trial: Kim and McVary 1995) that shows that the use of topical agents is not effective as treatment for erectile dysfunction in men with SCI.