Bosentan (bosentan)

Bosentan, an endothelin-receptor antagonist, is a vasodilator.

Bosentan, an endothelin receptor antagonist, improves exercise capacity and hemodynamics in patients with pulmonary arterial hypertension (PAH) by inhibiting the vasoconstricting effects of endothelin-1. Endothelin-1 (ET-1) concentrations have been shown to be elevated in plasma and lung tissue of patients with PAH, suggesting a pathogenic role for ET-1 in this disorder. Two ET-1 receptor subtypes, type A and type B, have been identified; activation of ET-1 type A receptors mediates vasoconstriction and smooth muscle cell proliferation, while activation of ET-1 type B receptors results in vasodilation and facilitates clearance of ET-1.

Bosentan exhibits specific and competitive antagonism of both endothelin type A and type B receptors in the endothelium and vascular smooth muscle, with slightly greater affinity for ET-1 type A receptors. The clinical importance of selective versus nonselective endothelin receptor blockade is not known.

After oral administration, maximum plasma concentrations of bosentan are attained within 3-5 hours and the terminal elimination half-life is about 5 hours in healthy subjects. Peak plasma concentrations achieved with the dispersible tablet are approximately 14% lower than those observed with the film-coated tablet, and AUC is approximately 11% lower. The absolute bioavailability of bosentan is approximately 50%.

Bosentan is 98% protein-bound. Bosentan is metabolized by cytochrome P-450 (CYP) isoenzymes 2C9 and 3A. The drug is eliminated principally by biliary excretion following metabolism in the liver; less than 3% of an orally administered dose is recovered in urine.

Bosentan has been shown to induce CYP2C9 and CYP3A and may possibly induce CYP2C19. Bosentan appears to induce its own metabolism following oral administration of multiple doses of the drug. Exposure to bosentan reaches a plateau at lower doses in pediatric patients than in adults, and doses higher than 2 mg/kg twice daily do not increase the exposure to bosentan in pediatric patients.

USES: Bosentan is used to treat high blood pressure in the lungs (pulmonary arterial hypertension). This condition is thought to be caused by increased levels of a certain natural substance (endothelin-1). This medication blocks the effects of endothelin-1, thereby helping to decrease the blood pressure in the lungs, slow the worsening of symptoms from the disease, and improve your ability to exercise.

Generic name: bosentan
Pronunciation: (boe-SEN-tan)

The following indications are listed for Bosentan:

• Pulmonary Arterial Hypertension

Also known as: Hypertensive Pulmonary Arterial Disease, Pulmonary Hypertensive Arterial Disease.

No ICD codes are available for this drug.