Drug interactions
Fedratinib + Tofacitinib
Severity: Major
Fedratinib and Tofacitinib: major interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Fedratinib inhibits CYP3A4 and CYP2C19, the two main enzymes clearing tofacitinib, so tofacitinib exposure may rise substantially. This increases the risk of dose-related adverse effects such as serious infection and cytopenias. Fedratinib itself causes myelosuppression, which adds to the concern.
What this interaction means in plain words
Fedratinib and Tofacitinib can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Fedratinib belongs to Oncology; Tofacitinib belongs to Musculoskeletal.
Why it happens
Combined inhibition of CYP3A4 and CYP2C19 decreases tofacitinib clearance.
What to do
Reduce the tofacitinib dose in line with labeling for combined moderate CYP3A4 and potent CYP2C19 inhibition, and monitor blood counts and signs of infection.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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Other interactions of Tofacitinib
- Baricitinib + Tofacitinib Contraindicated
- Cladribine + Tofacitinib Contraindicated
- Tofacitinib + Upadacitinib Contraindicated
- Abatacept + Tofacitinib Major
- Anti-thymocyte + Tofacitinib Major
- Antithymocyte globulin equine + Tofacitinib Major
Other interactions of Fedratinib
- Fedratinib + Thioridazine Contraindicated
- Amobarbital + Fedratinib Major
- Apalutamide + Fedratinib Major
- Brexpiprazole + Fedratinib Major
- Carbamazepine + Fedratinib Major
- Chloramphenicol + Fedratinib Major
Frequently asked questions
Can I take Fedratinib with Tofacitinib?
MediHelp rates the interaction as major. Fedratinib and Tofacitinib can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Fedratinib inhibits CYP3A4 and CYP2C19, the two main enzymes clearing tofacitinib, so tofacitinib exposure may rise substantially. This increases the risk of dose-related adverse effects such as serious infection and cytopenias. Fedratinib itself causes myelosuppression, which adds to the concern.
How serious is the interaction between Fedratinib and Tofacitinib?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Reduce the tofacitinib dose in line with labeling for combined moderate CYP3A4 and potent CYP2C19 inhibition, and monitor blood counts and signs of infection.
What other medicines interact with Tofacitinib?
MediHelp also lists interactions of Tofacitinib with, for example, Baricitinib, Cladribine, Upadacitinib. The full list is on the Tofacitinib page.
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