Valproic Acid and Apixaban: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Aug 8, 2026 · Source data updated Jul 11, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Apixaban
Valproic Acid
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
Here's what's going on. Apixaban (Eliquis) is a blood thinner that helps prevent dangerous blood clots. Valproic acid (like Depakote) may speed up how your body clears apixaban out. That could leave less apixaban in your blood than you need.
The concern is that your blood thinner might not work as well, which could raise your risk of a clot. I'll be honest, this is based mostly on how the drugs work in theory, not strong real-world proof. Please keep taking both exactly as prescribed and let your pharmacist or doctor know you take them together so they can watch over this for you.
Effect: Valproic acid may reduce apixaban exposure, risking subtherapeutic anticoagulation and thrombotic events.
- Mechanism: Proposed induction of P-glycoprotein efflux and possibly CYP3A4 by valproic acid, increasing apixaban clearance. Apixaban is the active drug (not a prodrug), so reduced exposure means reduced anticoagulant effect.
- Direction: Decreased apixaban AUC/Cmax, reduced PD effect.
- Evidence: Theoretical; magnitude and onset not established.
- Management: Combination generally not recommended. Assess thrombotic risk, consider an alternative anticoagulant or antiseizure agent, and monitor closely for signs of thromboembolism if co-prescribed.
What happens
Decreased apixaban exposure and possible subtherapeutic anticoagulation which could lead to a thrombotic event
Interaction Deep Dive
Combining apixaban with valproic acid is advised against because valproic acid lowers the plasma concentrations of apixaban1.
Why it happens (mechanism)
Induction of P-glycoprotein-mediated efflux transport by valproic acid; possible induction of CYP3A4-mediated metabolism by valproic acid
How to manage this interaction
The good news: your care team can manage this. Because valproic acid may lower apixaban levels, this combination is generally not recommended, but the decision is individualized.
- Keep taking both as prescribed unless your prescriber tells you otherwise. Do not stop either on your own.
- Ask your pharmacist or doctor whether an alternative to one of these medicines might be a better fit for you.
- Your team may monitor you more closely for signs a clot could be forming.
- Seek urgent care for symptoms like leg swelling or pain, chest pain, sudden shortness of breath, or trouble speaking.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
2 reports — tap to read
a) A markedly higher risk of stroke or systemic embolism was observed when direct-acting oral anticoagulant (DOAC) drugs were given together with valproic acid (adjusted OR, 2.38; 95% CI, 1.37 to 4.12) in a propensity-score adjusted nested case-control study involving patients with atrial fibrillation or recent DVT/PE (N=89,284). The patients were new users of DOAC therapy, comprising 54.8% on apixaban, 31.3% on rivaroxaban, and 14% on dabigatran. The findings were adjusted for demographic and lifestyle factors 2.
b) In a prospective cohort study of patients with nonvalvular atrial fibrillation who received direct-acting oral anticoagulant therapy (DOAC) together with antiepileptic drugs (N=91), the composite outcome of ischemic stroke, transient ischemic attack, and systemic embolism was seen in 9 patients (5.7% patient-year; 3 deaths) across a median follow up of 17.5 +/- 14.5 months; however, patients who had a thromboembolic event were older (75 years or greater), had a prior stroke, and a higher risk score (CHA(2)DS(2)-VASc greater than 3). Although no direct comparisons were performed, this rate of thromboembolic events was reported to exceed rates in cohort studies of patients with atrial fibrillation treated with DOAC therapy alone. Major bleeding was seen in 3 patients (1.9% patient-year; 1 death). In this study, 46.2%, 27.5%, 16.5%, and 9.9% of patients received apixaban, rivaroxaban, dabigatran, and edoxaban, respectively. Concurrent antiepileptic therapy included 45% receiving levetiracetam, 22% valproic acid, 12% phenobarbital, 11% carbamazepine, and 10% other antiepileptic therapy 3.
Common questions
Can I take Valproic Acid and Apixaban together?
Valproic acid may lower apixaban levels and weaken its clot protection, so this combo is generally not recommended. Keep taking both as prescribed and ask your pharmacist or doctor whether a change or closer monitoring is needed. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Valproic Acid and Apixaban interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How is the Valproic Acid and Apixaban interaction managed?
The good news: your care team can manage this. Because valproic acid may lower apixaban levels, this combination is generally not recommended, but the decision is individualized. Keep taking both as prescribed unless your prescriber tells you otherwise. Do not stop either on your own. Ask your pharmacist or doctor whether an alternative to one of these medicines might be a better fit for you. Your… Management is individual — always follow your own care team's guidance.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Valproic Acid or Apixaban need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there a safer alternative to one of these medications for me?
References (3)
- Steffel J, Collins R, Antz M, et al: 2021 European Heart Rhythm Association Practical Guide on the use of non-vitamin K antagonist oral anticoagulants in patients with atrial fibrillation. Europace 2021; 23(10):1612-1676.
- Gronich N, Stein N, & Muszkat M: Association between use of pharmacokinetic-interacting drugs and effectiveness and safety of direct acting oral anticoagulants: nested case-control study. Clin Pharmacol Ther 2021; 110(6):1526-1536. PubMed
- Giustozzi M, Mazzetti M, Paciaroni M, et al: Concomitant use of direct oral anticoagulants and antiepileptic drugs: a prospective cohort study in patients with atrial fibrillation. Clin Drug Investig 2021; 41(1):43-51. DOI
Keep reading about Apixaban
Keep reading about Valproic Acid
These medications also interact with supplements
Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
Check another combination
Our instant two-drug interaction checker is almost here.
Still have questions about this combination?
Every question gets a real answer from a licensed pharmacist — free, and usually within a day.
Ask the pharmacist