Prostaglandin E1 and papaverine: a comparative study on the ability to increase the penile bloodpool as measured by the 99mTc-penogram in the baboon model.

The evaluation of arterial blood supply and venous drainage of the penis is essential in assessing the impotent male. The vaso-active drugs prostaglandin E1 and papaverine, as intracavernous injections, cause penile erections in humans by influencing the arterial blood supply and venous drainage. These drugs were used in the normal baboon and in vascular compromised baboons using a 99mTc-penogram to quantify the vascular status of the penis. Ligation of the A. Iliaca Interna was performed to change the penile blood supply, thus compromising the vascular supply. It was observed that pre- and post-operatively, the increase in the penile bloodpool was more dramatic although not significantly so (P less than 0.05), but more variable after papaverine than with prostaglandin E1. The effect was even more enhanced (P less than 0.05) in the vascular compromised baboons so that the occurrence of priapism after papaverine can speculatively not be excluded. Also the more consistent vasoactive response after prostaglandin E1 seems to establish it as the superior intracavernous injectable agent.