Alprostadil

Alprostadil is a synthetic prostaglandin E1 (PGE1) analogue that acts as a vasodilator. It is used in several medical contexts where dilation of blood vessels is beneficial.

In neonatology, alprostadil is used to maintain the patency of the ductus arteriosus in certain congenital heart defects until surgical repair or stabilization. It is typically given by intravenous infusion and requires careful monitoring in a hospital setting because of potential respiratory and cardiovascular effects.

In adult medicine, alprostadil is used to treat erectile dysfunction. It can be delivered by intracavernosal injection or by intraurethral suppository. In some markets, a topical alprostadil cream or gel is available for ED as an alternative formulation. Brand names associated with these products include Caverject and Edex for injections, Muse for urethral dosing, and, in certain regions, Vitaros for topical use.

Mechanism of action: alprostadil activates prostaglandin receptors on smooth muscle, increasing cyclic adenosine monophosphate (cAMP) and causing relaxation of vascular and corporal smooth muscle. This leads to vasodilation and increased blood flow to targeted tissues, producing an erection or maintaining ductal patency, depending on the clinical context.

Safety and side effects: in neonates, adverse effects can include apnea, hypotension, and fever, requiring close monitoring. In ED use, common reactions include penile pain at the injection site, urethral burning with intraurethral dosing, and penile enlargement or prolonged erection (priapism). Rarely, fibrosis can occur with repeated injections. Alprostadil is contraindicated in patients using nitrates and in those with certain penile conditions or hypersensitivity.

Overview: alprostadil is a versatile PGE1 analogue employed to maintain ductus arteriosus in infants and to treat erectile dysfunction in adults, with formulation and dosing tailored to the clinical indication.