rivaroxaban + erythromycin

This is a **combination of rivaroxaban and erythromycin**, used concomitantly rather than as a fixed-dose product. - **Rivaroxaban** is an oral, direct factor Xa inhibitor anticoagulant, primarily used for the prevention and treatment of thromboembolic disorders (such as prevention of stroke in atrial fibrillation, treatment/prevention of deep vein thrombosis and pulmonary embolism). Its mechanism is inhibition of factor Xa, part of the coagulation cascade. - **Erythromycin** is a macrolide antibiotic that inhibits bacterial protein synthesis via binding to the 50S ribosomal subunit. It is also an inhibitor of the cytochrome P450 3A4 (CYP3A4) enzyme and P-glycoprotein transporter (P-gp). Co-administration of erythromycin with rivaroxaban increases rivaroxaban plasma concentrations due to inhibition of CYP3A4 and P-gp-mediated clearance, resulting in increased anticoagulant effect and a higher risk of bleeding. There is **no approved combination product** under this name; instead, the clinical relevance stems from the interaction of these two agents when prescribed together, requiring careful consideration due to the increased risk of bleeding and, for erythromycin, potential pro-arrhythmic effects via QT interval prolongation[1][3][7][4][2][5][6].