Feasibility of the Use of Phosphodiesterase Type 5 Inhibitors in a Pharmacologic Prevention Program for Recurrent Priapism

Abstract

Recurrent ischemic priapism is an enigmatic erectile disorder in need of improved clinical interventions to avert its known, potentially serious complications. To evaluate the use of a long-term, continuous phosphodiesterase type 5 (PDE5) inhibitor therapeutic regimen in controlling recurrent ischemic priapism and its feasibility in a clinical management program for the disorder. The main outcome measure was reduction in frequency or duration of priapism episodes. A secondary outcome measure was preservation of erectile ability. We retrospectively evaluated the clinical progress of seven patients (age 22-37 years) with sickle cell disease-associated "stuttering" priapism (N = 4) and idiopathic recurrent priapism (N = 3), who were counseled and consented to the "off-label" use of the PDE5 inhibitors sildenafil citrate and tadalafil. The medications were administered according to a specified therapeutic regimen based on scientific evidence that chronic PDE5 inhibitor administration in priapism contexts effectively reconditions PDE5 regulatory function in the penis. The duration of clinical follow-up extended through 2 years. All seven patients were confirmed to have recurrent ischemic priapism without identifiable pharmacologic, traumatic, or neoplastic disease associations based on clinical history, physical examination, laboratory testing, and penile diagnostics. PDE5 inhibitor treatment was successful in alleviating or resolving priapism recurrences in six of the seven patients. Erectile function was unchanged in six patients and improved in one patient at last follow-up compared with baseline status. All the patients reported that PDE5 inhibitor therapy was well tolerated and did not cause any adverse effects limiting their continued use of the medication. Because of their efficacy, safety, and tolerability as shown in this case series, PDE5 inhibitors would appear to have a possible role in a rigorously implemented clinical management program to control recurrent priapism. However, completion of a controlled clinical trial is necessary to confirm the utility of this treatment.