An aqueous formulation of alprostadil (prostaglandin E 1 ; - Upjohn) has been approved by the US Food and Drug Administration (FDA) for injection into the corpus cavernosum to treat erectile dysfunction. The drug is also marketed as Prostin VR, an alcohol-containing formulation, for intravenous use in newborns with congenital heart disease to maintain the patency of the ductus arteriosus.

Sildenafil citrate (Viagra - Pfizer) is the first oral drug approved by the FDA for treatment of erectile dysfunction. Alprostadil is also marketed for this indication but must be injected into the corpus cavemosum (Caverject) or pushed into the urethra (MUSE).

The prostaglandin alprostadil injected into the corpus cavernosum (Caverject - Upjohn) can produce an erection in some men with erectile dysfunction (Medical Letter, 37:83, 1995). Now a pellet (microsuppository) formulation has become available for intraurethral administration of alprostadil (MUSE [Medicated Urethral System for Erection] - Vivus). It is marketed in a sterile foil pouch containing a pellet 1.4 mm in diameter and 3 or 6 mm long within the stem of a hollow applicator, which is inserted 3 cm deep into the urethra. Pressing a button pushes the pellet into the urethra.

Sexual complaints related to desire, arousal, orgasm and painful intercourse are common in women. Since the last Medical Letter article on this subject, some new information has become available.