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Also known as
Prostaglandin E1, PGE1, PGE-1, l-Prostaglandin E1, Alprostadilum, Befar, Caverject, Caverject Impulse, Edex, Muse, Vitaros, Femprox, Topiglan, Alprox-TD, Liprostin, Prostandin, Prostin VR Pediatric, Prostavasin, Lipoprost, Promostan, Prostivas, l-PGE1, PGE1alpha, (11alpha,13E,15S)-11,15-dihydroxy-9-oxoprost-13-en-1-oic acid, (-)-Protaglandin E1
Definition
Alprostadil is a synthetic prostaglandin E1 (PGE1) analog primarily used as a second-line treatment for erectile dysfunction in males when oral therapy has failed.1 It works by binding as an agonist to prostaglandin receptors (e.g., EP2), thereby activating adenylate cyclase. This results in an accumulation of 3’5′-cyclic adenosine monophosphate (cAMP), which is responsible for the pharmacological effects of the medication, including smooth muscle relaxation that leads to vasodilation (increasing peripheral and intracavernosal blood flow), bronchodilation, and inhibition of platelet aggregation.1
Clinical Context
Alprostadil is FDA-approved as a second-line treatment for erectile dysfunction when first-line oral therapies such as phosphodiesterase type-5 (PDE5) inhibitors (e.g., sildenafil) prove ineffective.1 It can be administered via intracavernosal injection, intraurethral suppository, or topical cream.2 The drug works by relaxing the smooth muscle tissue of the corpus cavernosum, widening the cavernosal arteries, increasing blood flow and leading to an erection.1
For erectile dysfunction, alprostadil is available in several formulations:
- Intracavernosal injection: Alprostadil is the only FDA-approved agent for intracavernosal injections in the treatment of erectile dysfunction.1 Clinical trials have shown that intracavernosal alprostadil is effective in 70-80% of patients with erectile dysfunction.3
- Intraurethral suppository (MUSE – Medicated Urethral System for Erection): This less invasive alternative has shown efficacy in approximately 43% of patients.4
- Topical cream (Vitaros, Femprox): Topical alprostadil cream has proven to be effective and well-tolerated, increasing the erectile function score of the International Index of Erectile Function by up to 13 points from baseline.2 It offers a less invasive option with fewer systemic side effects.
Alprostadil can also be combined with other medications, such as in the formulation known as “Trimix,” which includes papaverine, phentolamine, and alprostadil.1 This combination is particularly effective when administered via intracavernous injection.
Beyond erectile dysfunction, alprostadil is also FDA-approved for temporarily maintaining ductus arteriosus patency in neonates with ductal-dependent congenital heart disease until surgical intervention.1 Other clinical applications include management of ischemic changes in patients with Raynaud phenomena, treatment of diabetic peripheral neuropathy, prevention of contrast-induced nephropathy, and post-liver transplant to improve hepatic vascular flow and reduce ischemia-reperfusion injury.1
Patient selection criteria for alprostadil therapy typically includes individuals who:
- Have failed or cannot tolerate oral PDE5 inhibitors2
- Have contraindications to PDE5 inhibitors (e.g., nitrate use)1
- Have erectile dysfunction of various etiologies (vasculogenic, psychogenic, or mixed causes)2
- Need a diagnostic test for erectile dysfunction3