Tamsulosin-induced priapism: A case report

Background

Priapism is a persistent erection generally lasting more than 4 h. Types of priapism include recurrent, ischemic, and non-ischemic and are generally classified based on penile arterial blood flow. Priapism can be induced by hematologic disorders (i.e. sickle cell anemia), infections, recreational drug use, and medication use. Tamsulosin is an α_1A receptor antagonist commonly used in the treatment of LUTS and benign prostatic hyperplasia (BPH).

Case report

We report a case of priapism lasting 48 hours due to tamsulosin. Aspiration and irrigation of the corpus cavernosa and intracavernosal injection of phenylephrine were performed without success. A penile blood gas revealed a pH of 6.92, pCO2 of 108 mmHg, pO2 of 40 mmHg, and HCO3 of 22.2 mmol/L—indicating ischemic priapism. A T-shunt was performed through the glans with moderate detumescence—the penis was able to bend at least 60° in all directions and 90° ventrally. The patient had a computed tomographic angiography (CTA) of the pelvis and a magnetic resonance angiography (MRA) 1 and 3 months later, respectively, which indicated proper flow and the absence of arteriovenous malformations.

Why should an EM Physician be aware of this?

Despite its attractive nature for the treatment of LUTS or BPH, because of α_1A receptor selectivity, tamsulosin should be recognized as a culprit of priapism. Because of the high affinity for the α_1A receptor, patients on tamsulosin may not respond to traditional medical therapies for priapism and therefore may require surgical intervention.