Endothelin-1 is a potent vasoconstrictor involved in vascular remodeling. There are three FDA-approved endothelin receptor antagonists (ERA) in the market for the treatment of pulmonary arterial hypertension (PAH), including bosentan, ambrisentan and macitentan. ERAs are used in PAH to improve exerc...

The FDA requires LFT testing before starting and every month thereafter for bosentan. For ambrisentan and macitentan, there is no requirement for monthly monitoring of LFTs due to the clinical trials data and post-marketing data demonstrating the safety of these medications. I routinely check LFTs d...

Every 3 months