6 The phosphodiesterase-5 inhibitor sildenafil is licensed for PAH in FC I–IV within the United states and FC II–III in Europe. Endothelin receptor antagonists (ERAs) which includes bosentan, sitaxentan and ambrisentan are oral therapies accredited to be used in PAH. As no oral agent has revealed superiority there remains discussion https://sergiozawrm.affiliatblogger.com/78101510/bosentan-secrets