Sildenafil citrate, a selective inhibitor of cyclic guanosine monophosphate
(cGMP)-specific phosphodiesterase type V (PDE V), initially designated as
compound 92-480-10 by Pfizer, was studied in the late 1980s as an antiangin
al. An unexpected side effect of the early clinical investigations was impr
oved erectile function among the men studied. This serendipitous finding ha
s transformed the field of erectile dysfunction therapy (1-3). The novelty
of this compound is its oral route of delivery and efficacy across a broad
range of etiologies. (C) 2000 Prous Science. All rights reserved.