Drug interactions
Apixaban + Phenobarbital
Severity: Major
Apixaban and Phenobarbital: major interaction.
Last updated Sources: UK SmPC
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
Phenobarbital is an inducer of CYP3A4 and P-glycoprotein and is expected to reduce apixaban exposure. This may cause loss of anticoagulant protection and thrombotic events. The effect is predicted from mechanism rather than extensively documented.
What this interaction means in plain words
Apixaban and Phenobarbital 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.
Why it happens
Enzyme and transporter induction by phenobarbital accelerates apixaban metabolism and efflux, lowering plasma levels.
What to do
Avoid the combination and use an alternative anticonvulsant or anticoagulant strategy. If unavoidable, monitor closely for thromboembolic events and consider an agent with a measurable effect such as warfarin.
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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References
Other interactions of Apixaban
- Apixaban + Dabigatran Contraindicated
- Apixaban + Defibrotide Contraindicated
- Apixaban + Edoxaban Contraindicated
- Apixaban + Ketorolac Contraindicated
- Apixaban + Mifepristone Contraindicated
- Abciximab + Apixaban Major
Frequently asked questions
Can I take Apixaban with Phenobarbital?
MediHelp rates the interaction as major. Apixaban and Phenobarbital 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. Phenobarbital is an inducer of CYP3A4 and P-glycoprotein and is expected to reduce apixaban exposure. This may cause loss of anticoagulant protection and thrombotic events. The effect is predicted from mechanism rather than extensively documented.
How serious is the interaction between Apixaban and Phenobarbital?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination and use an alternative anticonvulsant or anticoagulant strategy. If unavoidable, monitor closely for thromboembolic events and consider an agent with a measurable effect such as warfarin.
What other medicines interact with Apixaban?
MediHelp also lists interactions of Apixaban with, for example, Dabigatran, Defibrotide, Edoxaban. The full list is on the Apixaban page.
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