<prompt> Which is the best anti-hypeensive drug in pulmonary hypeension?BosentanAmlodipineFrusemideDigoxin  <response>: Endothelin receptor antagonist Bosentan is approved by US FDA and improves exercise tolerance in 6-minute walk test. Amlodipine Not approved by US FDA and only 20 respond to CCB in the long term. Diuretics Will worsen PAH Digoxin Used in CHF and no role in PAH 