The chemical Macitentan has a designated molecular formula of C19H20Br2N6O4S and a molecular weight of 588.275 g/mol. Synonyms may include: ACT-064992, Actelion-1, ACT064992, UNII-Z9K9Y9WMVL, ACT 064992, Opsumit (ChemID). Macitentan has been assigned a MeSH pharmacological action of: Endothelin A Receptor Antagonist, Endothelin B Receptor Antagonist.