Drug interactions
Apixaban + Fosphenytoin
Severity: Major
Apixaban and Fosphenytoin: major interaction.
Last updated Sources: US FDA label
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
Fosphenytoin is converted to phenytoin, a strong inducer of CYP3A4 and P-glycoprotein, which can reduce apixaban exposure. This may cause loss of anticoagulant effect and thromboembolic events.
What this interaction means in plain words
Apixaban and Fosphenytoin 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.
Apixaban belongs to Cardiovascular; Fosphenytoin belongs to Central Nervous System.
Why it happens
Induction of CYP3A4 and P-glycoprotein by phenytoin increases apixaban clearance.
What to do
Avoid combined use and choose a non-inducing anticonvulsant or a different anticoagulant with INR monitoring. If unavoidable, monitor for thromboembolic events.
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
Other interactions of Fosphenytoin
- Dronedarone + Fosphenytoin Contraindicated
- Fosphenytoin + Ledipasvir-sofosbuvir Contraindicated
- Fosphenytoin + Lorlatinib Contraindicated
- Fosphenytoin + Lurasidone Contraindicated
- Fosphenytoin + Ranolazine Contraindicated
- Fosphenytoin + Sofosbuvir-velpatasvir-voxilaprevir Contraindicated
Frequently asked questions
Can I take Apixaban with Fosphenytoin?
MediHelp rates the interaction as major. Apixaban and Fosphenytoin 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. Fosphenytoin is converted to phenytoin, a strong inducer of CYP3A4 and P-glycoprotein, which can reduce apixaban exposure. This may cause loss of anticoagulant effect and thromboembolic events.
How serious is the interaction between Apixaban and Fosphenytoin?
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 combined use and choose a non-inducing anticonvulsant or a different anticoagulant with INR monitoring. If unavoidable, monitor for thromboembolic events.
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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