Long Term Use Of Oral PDE-5 Inhibitors May Treat And Prevent Recurrent Priapism

Main Category: Erectile Dysfunction / Premature Ejaculation
Also Included In: Urology / Nephrology
Article Date: 20 Apr 2006 - 0:00 PDT

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UroToday.com - Priapism is a devastating condition in men that can result in long lasting deleterious effects on erectile function. Two types of priapism have been described: ischemic or non-ischemic (high flow). Occurrences of ischemic priapism are usually idiopathic or drug-related. Men with sickle cell trait/disease can especially be afflicted. Non-ischemic priapism is usually related to trauma. Priapism can present as an isolated episode or recurrent with attacks as frequent as everyday.

Based on previously published research linking dysregulated phosphodiesterase-5 (PDE-5) and ischemic priapism, Dr. Burnett and colleagues at Johns Hopkins University hypothesized that PDE-5 modulation may prevent or treat this condition.

They studied a total of 4 men (3 with Sickle Cell disease and 1 Idiopathic) with frequent episodes of priapism and administered either sildenafil citrate (25 or 50 mg) every morning or tadalafil (5 mg) three times weekly on a long-term basis.

Patients were followed and treated from 3-11 months with episodes of priapism significantly reduced to rare or occasional. The authors believe this encouraging response helps prove the dysregulated PDE-5 theory.

The authors concluded that the treatment with the PDE-5 inhibitors resets the dysregulation, thereby restoring normal function and protects against future recurrence.

By Raymond Pak, MD

Reference:
J Sex Med 2006; 3(Suppl 1): Abstract 20.
Link Here.
Burnett AL, Bivialacqua TJ, Chanmpion HC, Musicki B

Editorial Comment: Priapism is a devastating problem. In sickle cell patients it may be recurrent, often initiated by a normal nocturnal erection. These recurrent episodes are described in the older literature as 'stuttering'; the erections are evident up awakening and fail to subside after morning voids. A variety of techniques have been recommended: penile self-injection of alpha agonist, hormonal suppression with LHRH agonists, and hormonal interference with bicalutamide, baclofen and even placement of penile prosthesis.

This research and subsequent clinical trial of Sildenafil citrate is revolutionary, defying convention wisdom that this class of medications is contraindicated in priapism patients. The mechanism is counter intuitive to our traditional understanding, why should a penile vasodilator usually used to promote erection actually be of help in cases of recurring prolonged erection? Clearly the basic research is highly sophisticated, and based on a cellular regulatory model. For now I would advise practicing urologists to refer these men to centers of excellence for consideration of this and other off label treatments for stuttering priapism. The AUA Guidelines on Priapism [www.auanet.org] are a must read for practicing urologist and emergency department physicians who are faced with the medical emergency of priapism.

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