History of posttraumatic stress disorder · priapism · Dx?

A 35-year-old African-American man, who was an active duty service member, presented to the Troop Medical Clinic with a 4-hour history of priapism. He had been taking sertraline 100 mg and prazosin 10 mg nightly for 4 months to treat his posttraumatic stress disorder (PTSD) with no reported adverse effects. These doses were titrated 2 months prior to presentation. The patient reported that he took his usual medication doses before bed and awoke at 3 am with a penile erection. At 7 am, he presented to the clinic because of pain from the continued erection.