Letairis (generic: ambrisentan) is a prescription medication used to treat high blood pressure in the arteries of the lungs, known medically as pulmonary arterial hypertension (PAH). Letairis belongs to a group of drugs called endothelin receptor antagonists. It works by stopping the action of a natural substance that causes blood vessels to narrow in people who have PAH.

This medication comes in tablet form and is usually taken once a day, with or without food. Swallow tablets whole.

Common side effects of Letairis include swelling of hands, legs, and feet, stuffy nose, and hot flashes.