This article is from the Impotence FAQ, by Sine Nomine email@example.com with numerous contributions by others.
Right now, the only oral medication available outside of clinical
trials is Viagra (although you might get a doctor to prescribe
Vasomax; it's been approved for indications other than Erectile
Dysfunction). Viagra was approved in the US sometime in late March
1998 and should be available in drugstores by the end of April;
apomorphine is expected to be approved sometime in 1999. Vasomax has
not yet been submitted for FDA approval but is expected to be in time
for a 1998 approval. Yohimbine is available by prescription and in
health-food stores; it's very hard to be sure of the strength or
potency of over-the-counter yohimbine, though.