ORIGINAL RESEARCH—ED PHARMACOTHERAPY: Sildenafil Citrate Response Correlates with the Nature and the Severity of Penile Vascular Insufficiency

Abstract

ABSTRACT Introduction Sildenafil citrate is a highly effective erectogenic agent. However, predicting which patients will respond to this agent is often difficult. While the patient response to this agent is dependent on the nitric oxide–guanylate cyclase–cyclic guanosine monophosphate cascade, the integrity of penile arterial flow and venocclusive mechanism is also important. Duplex Doppler penile ultrasonography can reliably document penile hemodynamics. This study aimed at defining response rates based on degree of penile vascular sufficiency. Methods This study enrolled patients who met strict criteria for sildenafil citrate response who had also undergone penile ultrasound. Correlation was drawn between the nature and the severity of the vascular insufficiency and the response rate to sildenafil citrate. Results The distribution of vascular diagnoses was arteriogenic 64%, venogenic 6%, mixed vascular insufficiency 18%, and normal 12%. The best response was seen in those men with normal vascular studies, 80% responding. Fifty-three percent of all men with any abnormality on penile ultrasound responded; 65% of men with arteriogenic erectile dysfunction (ED), 25% of patients with venogenic ED, and 6% of men with a mixed vascular insufficiency were responders. There was a correlation between the degree of vascular impairment and the response rate. All men with venogenic ED who responded had mild leak. Conclusion These data demonstrate a correlation between the nature and severity of penile vascular disease and the ability to respond to sildenafil citrate. These data may be useful to the sexual medicine practitioner when counseling patients regarding oral erectogenic therapy.