Experts Discuss Use of High-dose Phenylephrine for Ischemic Priapism

Using higher doses of phenylephrine appears to have good results in a small series of men with ischemic priapism, according to a recent study in the Journal of Sexual Medicine.

Priapism is an erection that lasts for several hours. Normally, when a man has an erection, his penis becomes engorged with blood. Veins constrict to keep the blood in the penis and keep the erection firm. After the man ejaculates – or once sexual stimulation ends – this blood flows back into the body.

Ischemic priapism (sometimes called low-flow) priapism occurs when the blood does not leave the penis. This type of erection can be painful and last for hours, sometimes longer a than a day. The situation is a medical emergency and can result in tissue damage and erectile dysfunction (ED) if not treated quickly.

Treatment options include aspiration (draining the penis with a needle and syringe), injected medication that allows blood to drain out, or surgery that redirects the blood flow.

One medication used to treat ischemic priapism is phenylephrine, which is injected into the penis at various concentrations and doses. The American Urological Association (AUA) and European Association of Urology (EAU) have issued dosage guidelines, but select physicians routinely use higher concentrations and doses. In this study, one group reported on their experiences with this protocol.

They looked at data from 58 patients between the ages of 18 and 65 who sought emergency care for ischemic priapism between 2010 and 2015. Some of the patients were treated more than once. Overall, there were 136 emergency room visits.

All of the men received phenylephrine injections ranging from 200-1000 μg with each injection, with total amounts of 0.3-12 mg instilled. Overall, the treatment was successful for 86% of the patients and in 94% of the emergency room visits. Men who were treated within 12 hours of the start of priapism tended to have better results. No complications were reported.

More research is still needed, however. The study authors noted that their work is retrospective (looking back in time) and did not have a control group. It is important to learn more about the effectiveness and safety of high-dose phenylephrine and to determine the most appropriate dosage.

Experts caution that further study is required before routine adoption of the higher dose protocol, as the potential complications of high doses of intravascular phenylephrine could be lethal and have been reported to cause cerebrovascular hemorrhage in rare cases. It is recommended to closely monitor the blood pressure of these patients and to inject phenylephrine slowly to avoid egress of the phenylephrine from the corporal bodies into the systemic circulation.

Resources

International Society for Sexual Medicine

“How is priapism treated?”
http://www.issm.info/sexual-health-qa/how-is-priapism-treated/

“Why is priapism an emergency?”
http://www.issm.info/sexual-health-qa/why-is-priapism-an-emergency

The Journal of Sexual Medicine

Douglas G. Ridyard, MD, et al.
“Use of High-Dose Phenylephrine in the Treatment of Ischemic Priapism: Five-Year Experience at a Single Institution”
(Full-text. First published online: September 27, 2016)
http://www.jsm.jsexmed.org/article/S1743-6095(16)30412-X/fulltext

Mayo Clinic

“Priapism”
(July 8, 2016)
http://www.mayoclinic.org/diseases-conditions/priapism/home/ovc-20208946