Ambrisan 5 mg Tablet is a medication used for the treatment of Pulmonary Arterial Hypertension (PAH), which is high blood pressure in the arteries of the lungs. It contains the active ingredient Ambrisentan, an endothelin receptor antagonist. By blocking the action of endothelin-1, a substance that causes blood vessels to constrict, Ambrisan helps relax and widen the blood vessels in the lungs, thus reducing pulmonary artery pressure and improving blood flow. This leads to enhanced exercise capacity and may delay the progression of PAH. It is usually prescribed either alone or in combination with other medications like tadalafil for more effective management of PAH.