The clinical effects of a new self-injection pen were investigated in 160 impotent patients undergoing intracavernous vasoactive pharmacotherapy. Of the patients previously using insulin syringes for self-injection 90% switched to the pen, since it was considered easier to use and several injections could be performed with the same drug cartridge, thus avoiding the preparation necessary before every single injection with the syringe. Dropout rates were 36% and 12% for patients using the syringe and the pen, respectively (p < 0.05). This self-injection pen can be used for any drug, either singly or in combination with others. It is well accepted by patients, and greatly increases acceptance of and satisfaction with intracavernous pharmacotherapy.