Sildenafil for pulmonary arterial hypertension

Pulmonary arterial hypertension is a disease characterized by progressive obliteration of the pulmonary vasculature leading to right-ventricular failure and if untreated, death. Several effective therapies are now available for pulmonary arterial hypertension. These therapies target specific abnormalities in the endothelium, including prostacyclin and nitric oxide deficiencies, and endothelin excess. Sildenafil, a phosphodiesterase type-5 inhibitor, has garnered interest recently for the treatment of pulmonary arterial hypertension because it increases cyclic GMP--a second messenger in the nitric oxide pathway. Early studies suggested a favorable response with traditional measures of a 6-min walk and hemodynamics in pulmonary arterial hypertension patients. Recently, sildenafil was approved by the US Food and Drug Administration and the European Medicines Agency under the trade name Revatio (Pfizer, Inc.). Sildenafil is well tolerated and adverse events have been shown to be mild and transient. Potential benefits of sildenafil therapy include its ease of administration and safety profile.