This article is from the Impotence FAQ, by Sine Nomine firstname.lastname@example.org with numerous contributions by others.
MUSE (Medicated Urethral Suppository for Erection) is a small pellet
of alprostadil (PGE1, the active ingredient in Caverject) and a
plastic device for placing it in the urethra. Unlike injectables, MUSE
comes in only four set doses (125 mcg, 250 mcg, 500 mcg, and 1000 mcg)
-- you can't adjust your dose beyond that.