Bosentan

Class

• dual endothelin receptor antagonist

Mechanism of Action

• competitive antagonism of endothelin-1 (pulmonary vasoconstrictor) at the endothelin receptors -> decreases PVR

Pharmaceutics

• tablet

Dose

• 62.5mg BD -> increased monthly

Indications

(1) severe PHT
(2) scleroderma with digital ulcers

Adverse Effects

• liver injury
• teratogenicity

PK

• Absorption – bioavailability = 50%
• Distribution – protein binding 98%
• Metabolism – hepatic
• Elimination – t ½ = 5 hrs

Evidence