Intracavernous drug delivery system: an alternative to intracavernous injection in the treatment of impotence?

In 6 monkeys, the feasibility of chronic intracavernous drug application via a permanent intracavernous catheter was examined. In 4 monkeys, a combination of papaverine (15 mg/ml) and phentolamine (0.5 mg/ml) was injected via the drug delivery system; in 2 monkeys each, 30 or 100 injections were done. As a control, saline was injected in 2 monkeys. The dose of the papaverine-phentolamine mixture to induce full erection had to be increased by a mean of 240%, comparing the 1st to the 30th injection. The dose then remained stable. After 100 injections, penile histology showed a thin fibrotic layer around the implantation site of the catheter. Beside slight smooth muscle hypertrophy in the papaverine-phentolamine group, there were no abnormal findings in the proximal and medical part of the cavernous bodies. The distal part of the cavernous bodies showed extensive fibrosis due to mechanical irritation by the tip of the intracavernous catheter. Given appropriate selection and indication, implantation of an intracavernous drug delivery system may be an alternative to chronic intracavernous injection in the treatment of impotence.