Intracavernous Injection of Papaverine for Erectile Failure R. Virag
I n 1982 in a letter to the editor of The Lancet [1], Virag exposed to the English literature the ability of an intracavernous injection of papaverine to induce an erection. He stated that an accidental intracavernous injection of that drug during an arterial epigastric cavernous anastomosis [2], a vascular procedure proposed to treat vasculogenic erectile dysfunction (ED), had produced a rigid erection for 2 hours. After this finding, Virag decided to study the effect of papaverine in the physiology of erection. He studied 15 patients with organic ED and 10 with non-organic ED. Eighty milligrams of papaverine were injected into one corpora cavernosa and continuous recording of intracavernous pressure (ICP) was done through a 21 G needle inserted in the contralateral corpora cavernosa. Duplex ultrasound and pulse plethysmography were used for continuous monitoring of penile arterial vessels. In same cases, selective bilateral internal iliac angiography was performed. After papaverine injection, there was an ICP increase; this increase was higher when patient were under general anesthesia (mean of 70 mm Hg against 40 mm Hg without anesthesia). An increase on arterial flow was seen by duplex ultrasound, pulse plethysmography, and angiography; the peak effect was seen after 2–15 minutes after injection and lasted from 10 to 120 minutes. According to Virag, 7 out of 15 patients with organic ED reported improvement on their erections in the days following the study. All of seven had arterial ED. There was no improvement on patients with non-organic ED. Based on those results, Virag started a “conservative therapy” in 30 patients with ED who had Doppler and arteriographic evidence of penile arterial insufficiency, including 12 with diabetes mellitus. Patients received an intracavernous injection of 80 mg of papaverine and after 15 minutes, an infusion of saline with 1% of heparin via an infusion pump until they reached a rigid erection which was maintained for 15 minutes. The procedure was performed without anesthesia and was repeated after 2 months and every third month after that. Of the 14 patients who had at least two procedures, called by Virag as artificial erections, four returned to their “normal sexual life,” nine reported significant improvement in their penile rigidity, and one had no change in his erectile function. Virag concluded that papaverine was a powerful smooth-muscle relaxant, possibly acting as phosphodiesterase inhibitor or with an antinicotinic effect; to him, artificial erections were associated to vasodilation of pudendal arteries branches and with a possible “mechanical action” at the level of cavernous tissue. Sidney Glina