abemaciclib + rifampin

Abemaciclib + rifampin refers to the coadministration of **abemaciclib**, an oral small molecule inhibitor of cyclin-dependent kinases 4 and 6 (CDK4/6), and **rifampin**, an antibiotic and potent inducer of cytochrome P450 3A (CYP3A). Abemaciclib is used primarily in the treatment of hormone receptor-positive, HER2-negative advanced or metastatic breast cancer, often in combination with endocrine therapy. Its mechanism involves the inhibition of CDK4/6, which prevents cell-cycle progression from G1 to S phase, thereby arresting proliferation of cancer cells. Rifampin notably affects the pharmacokinetics of abemaciclib by strongly inducing CYP3A, leading to a substantial decrease in abemaciclib’s plasma concentrations and therapeutic effect[1][3][5]. The combination is contraindicated or should be avoided due to reduced efficacy of abemaciclib and increased risk of treatment failure[1][3][5].

Brand names

VerzenioRifadin

Other names

abemaciclib + rifampicin