On the basis of reports describing nitric oxide as a form of endotheli
um-derived relaxing factor and on our own experience with intracaverno
us use of nitric oxide-releasing substances in animal models, we under
took an approved human study of intracavernous sodium nitroprusside as
a treatment for impotence. We report our early experience in which se
vere hypotension and only mild tumescence in our first 3 patients caus
ed us to discontinue the trial.