Drug interactions
Cimetidine + Fedratinib
Severity: Major
Cimetidine and Fedratinib: 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
Cimetidine is a nonselective CYP inhibitor and may raise fedratinib exposure, increasing risks such as GI toxicity, myelosuppression and, notably, encephalopathy. The combination has not been studied.
What this interaction means in plain words
Cimetidine and Fedratinib 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.
Cimetidine belongs to Gastrointestinal Tract; Fedratinib belongs to Oncology.
Why it happens
Cimetidine inhibits CYP3A4 and CYP2C19, which metabolize fedratinib, and may reduce its clearance.
What to do
Prefer famotidine or another non-inhibiting acid suppressant. If a strong CYP3A4 inhibitor must be used, reduce the fedratinib dose per labeling and monitor for neurologic symptoms, blood counts and GI toxicity.
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 Cimetidine
- Cimetidine + Dofetilide Contraindicated
- Cimetidine + Fezolinetant Contraindicated
- Alfentanil + Cimetidine Major
- Atazanavir + Cimetidine Major
- Carmustine + Cimetidine Major
- Cimetidine + Citalopram 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 Cimetidine with Fedratinib?
MediHelp rates the interaction as major. Cimetidine and Fedratinib 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. Cimetidine is a nonselective CYP inhibitor and may raise fedratinib exposure, increasing risks such as GI toxicity, myelosuppression and, notably, encephalopathy. The combination has not been studied.
How serious is the interaction between Cimetidine and Fedratinib?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Prefer famotidine or another non-inhibiting acid suppressant. If a strong CYP3A4 inhibitor must be used, reduce the fedratinib dose per labeling and monitor for neurologic symptoms, blood counts and GI toxicity.
What other medicines interact with Cimetidine?
MediHelp also lists interactions of Cimetidine with, for example, Dofetilide, Fezolinetant, Alfentanil. The full list is on the Cimetidine page.
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