Update on the clinical utility of sildenafil in the treatment of pulmonary arterial hypertension

Abstract

Sildenafil is an orally administered phosphor diesterase type 5 inhibitor that is approved for the treatment of pulmonary arterial hypertension (PAH). The hemo dynamic effects of sildenafil are mitigated primarily via potentiating the effects of endogenous nitricoxide, leading to smooth muscle cell relaxation and reductions in pulmonary arterial pressures and pulmonary vascular resistance. When added to standard background therapy in patients with idiopathic or associated PAH from congenital heart disease, anorexigen use, or connective tissue disease, sildenafil treatment results in improved exercise capacity as measured by6 minute walk distance, improved hemo dynamics, and favorable changes in quality of life. Sildenafil use is contraindicated with concomitant nitrate administration, and caution should be exercised when used in combination with antihypertensive agents due to risks of precipitating hypotension. Side effects are generally mild, and include flushing, headaches, and epistaxis. The combination of sildenafil with intravenous epoprostenol is safe and well tolerated, and further improves exercise capacity. Sildenafil is approved only for treatment of PAH, and although hemerging data suggest a potential role in treating other types of pulmonary hypertension, larger trials are required to confirm these findings. © 2010 Ramani and Park, publisher and licensee Dove Medical Press Ltd.