Regarding alprostadil pharmacotherapy in ED:a. Prostaglandin E1 cause vasoconstriction of penile veins
Prostaglandin E1 causes direct relaxation of cavernosal smooth muscle and antagonises the action of norepinephrine. These dual effects may explain its efficacy in inducing erections. The Alprostadil Study Group reported a 2% incidence of penile fibrosis. Pain is the major problem associated with alprostadil injection, with an incidence of 16% to 40% and a clear dose dependency. Alprostadil has a higher rate of penile pain compared to papaverine. Prolonged erection occurred in 5% of the men in the Alprostadil Study Group.