Oral therapies for pulmonary arterial hypertension: endothelin receptor antagonists and phosphodiesterase-5 inhibitors.

The development of orally active pulmonary vasodilators has been a major breakthrough in the treatment of pulmonary arterial hypertension (PAH). Orally active medications greatly enhanced patient access to PAH treatment and increased an interest in the diagnosis and treatment of this disease that still continues. Four different orally active drugs are currently available for the treatment of PAH and several more are undergoing evaluation. This article discusses the mechanisms by which endothelin receptor antagonists and phosphodiesterase-5 inhibitors mitigate pulmonary hypertensive responses, and reviews the most recent data concerning their efficacy and limitations in the treatment of PAH.