Ischemic priapism is not uncommonly encountered in the emergency department (ED) and essentially results in a compartment syndrome of the penis. Thus, time is erectile tissue. The prolonged erection in ischemic priapism leads to tissue edema and ultimately necrosis of the corpus cavernosa, with irreversible damage occurring after 24 hours. The best chance to reduce long-term sequelae is through rapid detumescence.

The American Urological Association (AUA) released updated guidelines for the management of acute ischemic priapism that take a stab at treating the condition more efficiently. There are two primary takeaways. First, don’t waste time with conservative treatment in the ED. If you use conservative measures, at least use them concurrently with more definitive treatment. Second, an intracavernosal injection of phenylephrine or another sympathomimetic should be used up front in the treatment of ischemic priapism.¹

Conservative measures, such as exercise or oral agents (pseudoephedrine, an alphaadrenergic agonist or terbutaline, a beta-agonist), for the treatment of ischemic priapism are alluring. Aspiration and injection generally require a multistep process of dorsal nerve blocks and instrumentation of the penis. And, of course, patients would much prefer a pill over management involving injection of an extremely sensitive area. For physicians, aspiration and injection can be time consuming. Despite the allure, it seems unlikely that an oral agent could achieve sufficient concentrations in an area with reduced blood flow due to outflow obstruction; studies confirm inconsistent effects.

In one study of 53 patients who had prolonged erections after receiving intracavernosal injections for evaluation of erectile dysfunction, approximately 66% of prolonged erections resolved after 30 minutes of exercise—walking up and down stairs (39.6%)—or an oral beta-agonist (26.9%).² Although many patients did not require aspiration and/or intracavernosal injections, these patients are likely different than those who present to the ED. These conservative treatments delay definitive management. In another study of 75 patients who had a prolonged erection after receiving prostaglandin injections for erectile dysfunction, oral medical therapy (pseudoephedrine, terbutaline, or placebo) was unsuccessful in 75 percent of patients.³ Other small studies found no benefit to terbutaline over placebo.4 The data on the effectiveness of conservative measures for patients who present to the ED for care are minimal, inconsistent, or derived from a different population than general ED patients with acute ischemic priapism. Given the time-critical nature of acute ischemic priapism, current data do not support routine use of these conservative measures in the ED population.

Fresco in Pompeii depicting Priapus, the Greek god of fertility and male genitalia, for whom the condition is named after. (Click to enlarge.)

The presurgical management of ischemic priapism has often involved a stepwise approach, with initial aspiration of blood from the corpus cavernosa to relieve the venous outflow obstruction, followed by intracavernosal injections of a sympathomimetic, usually phenylephrine, if aspiration was unsuccessful. However, data suggest that resolution rates are higher with initial combined strategies (i.e., aspiration and phenylephrine) compared with either alone. In fact, injections of phenylephrine alone (with a 31-gauge needle) are sufficient for some patients. The guidelines state, “Clinicians treating acute ischemic priapism may elect to proceed with alpha adrenergics, aspiration with saline irrigation, or a combination of both therapies, based on clinical judgment.” The guidelines also now recommend that, in patients with prolonged erections after intracavernosal injections of vasoactives for erectile dysfunction, clinicians use intracavernosal injections of phenylephrine as first-line treatment.¹

Phenylephrine is a pure alpha-adrenergic agonist, which can contract the cavernosa smooth muscle and alleviate the venous outflow obstruction of ischemic priapism. The guidelines recommend injection of 100-500 mcg of phenylephrine every three to five minutes because there is insufficient evidence to support an optimal dose. However, several retrospective studies provide insight on how much phenylephrine it typically takes.

One study of 136 cases of priapism in 58 patients revealed that 65 percent were treated with phenylephrine alone, with a median total dosage of 1,500 mcg (range 300–12,000 mcg). Of note, patients with priapism fewer than 36 hours in duration received less phenylephrine (median of 1,400 mcg) compared with those with a duration greater than 36 hours (median 3,500 mcg).⁵ In another study of 74 patient encounters, the median dose of phenylephrine was 1,000 mcg (IQR 500-2000 mcg).6 Despite relatively large doses of phenylephrine, no adverse events or increases in heart rate or blood pressure were reported in either study.^5,6 Although dose adjustments may be prudent in those with significant cardiovascular disease and in pediatric patients, 500 mcg is likely the most efficient initial dose.

The guidance to use phenylephrine up front for most patients may help reduce morbidity by decreasing time to detumescence; however, a plan for an injectable phenylephrine-first approach (plus or minus aspiration) may help with ED efficiency. Clinicians can ensure that the proper phenylephrine concentration (500 mcg/mL or 1,000 mcg/mL, ideally pre-mixed for safety) is available and ready. Further, targeting the initial dose to 500 mcg in most patients may reduce the number of attempts and the time to detumescence.

Dr. Westafer (@Lwestafer) is an attending physician and research fellow at Baystate Medical Center, clinical instructor at the University of Massachusetts Medical School in Worcester, and co-host of FOAMcast.

References

1. Bivalacqua TJ, Allen BK, Brock GB, et al. The diagnosis and management of recurrent ischemic priapism, priapism in sickle call patients, and nonischemic priapism: an AUA/SMSNA guideline. J Urol. 2022;208(1):43-52.
2. Habous M, Elkhouly M, Abdelwahab O, et al. Noninvasive treatments for iatrogenic priapism: Do they really work? A prospective multicenter study. Urol Ann. 2016;8(2):193-196.
3. Lowe FC, Jarow JP. Placebo-controlled study of oral terbutaline and pseudoephedrine in management of prostaglandin E1-induced prolonged erections. Urology. 1993;42(1):51-53.
4. Govier FE, Jonsson E, Kramer-Levien D. Oral terbutaline for the treatment of priapism. J Urol. 1994;151(4):878-879.
5. Ridyard DG, Phillips EA, Vincent W, et al. Use of high-dose phenylephrine in the treatment of ischemic priapism: Five-year experience at a single institution. J Sex Med. 2016;13(11):1704-1707.
6. Sidhu AS, Wayne GF, Kim BJ, et al. The hemodynamic effects of intracavernosal phenylephrine for the treatment of ischemic priapism. J Sex Med. 2018;15(7):990-996.