sitaxsentan + rifampin

**Sitaxsentan + rifampin** is a combination of two pharmaceuticals: sitaxsentan, a selective endothelin receptor antagonist (ERA), and rifampin, a broad-spectrum antibiotic and potent inducer of certain liver enzymes. Sitaxsentan acts by competitively blocking endothelin-1 from binding its receptors on smooth muscle cells, thereby leading to vasodilation and reduced pulmonary vascular resistance. Sitaxsentan’s primary use was in pulmonary arterial hypertension (PAH), though it has been discontinued globally due to hepatotoxicity concerns. Rifampin is used primarily to treat tuberculosis and other bacterial infections; pharmacologically, it strongly induces enzymes CYP3A4 and CYP2C9. When co-administered, rifampin significantly increases the metabolism of sitaxsentan, lowering its plasma concentration and potentially reducing efficacy. This combination has no approved clinical indication and interaction carries a risk of decreased therapeutic effect and increased adverse reactions.

Brand names

Thelin

Other names

sitaxsentanrifampicin