Valproic Acid and Dabigatran: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Dabigatran
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.
What happens
Decreased dabigatran exposure and possible subtherapeutic anticoagulation which could lead to a thrombotic event
Interaction Deep Dive
Concomitant use of dabigatran with valproic acid is not recommended due decreased dabigatran plasma levels1.
Why it happens (mechanism)
Induction of P-glycoprotein-mediated efflux transport by valproic acid; possible induction of CYP3A4-mediated metabolism by valproic acid
Literature reports
2 reports — tap to read
a) A significantly increased risk of stroke/systemic embolism was noted with administration of direct-acting oral anticoagulant (DOAC) drugs concomitantly with valproic acid (adjusted OR, 2.38; 95% CI, 1.37 to 4.12) in a propensity-score adjusted nested case-control study of patients with atrial fibrillation or recent DVT/PE (N=89,284). Patients were new users of DOAC therapy and included 54.8% on apixaban, 31.3% on rivaroxaban, and 14% on dabigatran. Results were adjusted for demographic and lifestyle variables 2.
b) In a prospective cohort study of patients with nonvalvular atrial fibrillation receiving direct-acting oral anticoagulant therapy (DOAC) concomitantly with antiepileptic drugs (N=91), the composite outcome of ischemic stroke, transient ischemic attack, and systemic embolism occurred in 9 patients (5.7% patient-year; 3 fatalities) over a median follow up of 17.5 +/- 14.5 months; however, patients who experienced a thromboembolic event were older (75 years or greater), had a history of stroke, and a higher risk score (CHA(2)DS(2)-VASc greater than 3). Although no direct comparisons were made, this incidence of thromboembolic events was noted to be higher than rates in cohort studies of patients with atrial fibrillation treated with DOAC therapy alone. Major bleeding occurred in 3 patients (1.9% patient-year; 1 fatality). In the study, 46.2%, 27.5%, 16.5%, and 9.9% of patients received apixaban, rivaroxaban, dabigatran, and edoxaban, respectively. Concomitant 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 Dabigatran together?
Decreased dabigatran exposure and possible subtherapeutic anticoagulation which could lead to a thrombotic event Always confirm with your pharmacist or prescriber before making any change.
How serious is the Valproic Acid and Dabigatran 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 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 Dabigatran 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. DOI
- 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. PubMed
Keep reading about Dabigatran
Keep reading about Valproic Acid
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