Penile erection is a complex neurovascular event that represents a bal
ance between corporal smooth muscle relaxation and contraction. This b
alance is determined by the interaction between proerectile and antier
ectile neurotransmitters. It is believed that nitric oxide is the prim
ary erectogenic neurotransmitter and that noradrenaline (norepinephrin
e) is the primary erectolytic neurotransmitter. There are a number of
pharmacological approaches to the management of erectile dysfunction a
nd manipulation of the neurotransmitter systems. These involve direct
delivery of drugs into the erectile chambers (intracavernosal injectio
n therapy), administration of medications into the urethra (transureth
ral delivery), application of medications to the skin (transdermal del
ivery) and it is hoped that oral agents will be available in the very
near future. This article reviews the world literature on the medicati
ons that have been investigated to date and their delivery routes.