Ivacaftor and Rifabutin interaction
Ivacaftor and Rifabutin: both prescribing labels describe an interaction that usually calls for monitoring, a dose change, or spacing the doses.
Usually manageable with monitoring or a dose change. Tell your pharmacist you take both.
What the FDA labels say
From the Ivacaftor (Kalydeco) label · effective 2026-03-23
Concomitant Use with CYP3A Inducers Use of KALYDECO with strong CYP3A inducers, such as rifampin, substantially decreases the exposure of ivacaftor, which may reduce the therapeutic effectiveness of KALYDECO.
Inducers of CYP3A Co-administration with rifampin, a strong CYP3A inducer, significantly decreased ivacaftor exposure (AUC) by approximately 9-fold.
Use with CYP3A inducers: Concomitant use with strong CYP3A inducers (e.g., rifampin, St.
Therefore, co-administration of KALYDECO with strong CYP3A inducers (e.g., rifampin, St.
Therefore, co-administration with strong CYP3A inducers, such as rifampin, rifabutin, phenobarbital, carbamazepine, phenytoin, and St.
From the Rifabutin label · effective 2026-09-01
Effect of Other Drugs on Rifabutin Pharmacokinetics Some drugs that inhibit CYP3A may significantly increase the plasma concentration of rifabutin.
Therefore, carefully monitor for rifabutin associated adverse events in those patients also receiving CYP3A inhibitors, which include fluconazole and clarithromycin.
In some cases, the dosage of rifabutin may need to be reduced when it is co-administered with CYP3A inhibitors.
Antiretroviral and Anti-HCV Drug Interactions Protease inhibitors act as substrates or inhibitors of CYP3A4 mediated metabolism.
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.