First off, you must know the difference between ischemic and non-ischemic priapism. You just need to think about either the patient’s underlying disease process or a medication they took that caused the priapism. The classic example of ischemic priapism is in a patient with sickle cell disease, whereas the non-ischemic priapism can be seen in patients that took nitrates/phosphodiesterase inhibitors. Also, the erection must have been present for at least four hours to be called a priapism.
The management of the ischemic priapism may or may not involve medications. The American Urologic Association has an algorithm for the approach to the management of ischemic priapism, but it was last updated in 2003. They recommend either going directly to aspiration/irrigation or starting with penile phenylephrine injection. The urology literature no longer supports the use of oral sympathomimetic agents such as terbutaline or pseudoephedrine, although these recommendations are still out there. Many people are of the belief that there is little downside to trying one of these oral medications PO while you get the phenylephrine from the pharmacy. The dose of terbutaline is one dose at 5-10 mg PO followed by a similar dose approximately 15 minutes later. One study quoted this as working in one third of patients, but other studies give much poorer results. The oral pseudoephedrine dose is 60-120 mg, and no studies have shown that it works. If you give these, wait only 30 minutes to see if they work before trying something different.
The next medications in the algorithm are alpha-adrenergic sympathomimetics injected directly into the corpus carvernosum. The most common are phenylephrine and ephedrine. To make the phenylephrine solution, mix one ampule of phenylephrine (1 mL: 1,000 mcg) with 9 mL of normal saline. Then inject 0.3 to 0.5 mL of this solution into the corpus cavernosum every 15 minutes as needed using a 29-gauge needle. If this doesn’t work, it’s probably time for aspiration.
American Urological Association. Priapism: Guideline on the management of priapism. 2003.
Burnett, A; Bivalacqua, A; Priapsim: New concepts in medical and surgical management. Urologic Clinics of North America. May, 2011: 38(2)
Dougherty, C. Priapism in Emergency Medicine Medication. Emedicine.com Nov 17, 2009.