Effect of Oral Sildenafil on Skin Postocclusive Reactive Hyperemia in Healthy Volunteers

Abstract

Sildenafil is a type 5 phosphodiesterase inhibitor that has a theoretical ability to increase hyperemia following a short bout of ischemia. We tested if oral sildenafil increases skin PORH in healthy volunteers. We assessed forearm skin PORH (occlusion of blood flow for five minutes) in ten healthy volunteers 120minutes following the oral administration of 50 or 100mg of sildenafil. Cutaneous blood flow on the forearm was monitored using LDF. The PORH peak, expressed as a percentage of baseline, was clearly increased with 100mg sildenafil: 746% (95% CI 447-1044) versus 484% (95% CI 354-613) with 50mg sildenafil, and 468% (95% CI 347-588) without sildenafil (p=0.03 for 100mg versus 50mg and control). Oral sildenafil at 50mg increased the AUC of PORH on the forearm compared with control: 4568PU.sec (95% CI: 2252-6883) with 50mg sildenafil versus 1030 PU.sec (95% CI 737-1322) without sildenafil (p=0.006). Likewise, 100mg sildenafil increased the AUC (5271PU.sec (95% CI -81-10,623), albeit bordering on significance (p=0.07). Neither dose increased maximal LTH. Acute sildenafil administration at 50 and 100mg enhances skin hyperemia following a short bout of ischemia.