Which of the following is not true about bosentan

Ans. is 'b' i.e., used in malignant hepatitis Endothein receptor antagonists There are two endothelin receptor subtypes - ETA and and ETB. Bosentan is a nonselective endothelin antagonist - blocks both ETA and ETB. Bosentan is active intravenously and orally. Bosentan is currently approved for use in pulmonary hypeension. Tezosentan another nonselective antagonist is used investigation for the treatment of acute hea failure. Sitaxentan and ambrisentan are selective ETA antagonists. Phosphoramidon inhibits formation of endothelin by inhibiting endothelin conveing enzyme. Remember Bosentan can cause severe hepatotoxicity - monthly liver function tests should be done. It is contraindicated in pregnancy.