- Design
- Scoping review following PRISMA-ScR
- Population
- 30 clinical reports and observational datasets of antiseizure drug and DOAC co-prescription
- Primary outcome
- DOAC concentrations and clinical outcomes
- Effect
- Enzyme inducers consistently linked to subtherapeutic DOAC levels and serious failures; dose doubling did not prevent events in several cases
This scoping review gathered clinical reports of patients taking an antiseizure medication together with a DOAC. Thirty studies met the criteria.
Enzyme-inducing antiseizure drugs were repeatedly associated with low DOAC concentrations and serious clinical failures, such as strokes and venous clots. Increasing the DOAC dose did not reliably compensate. Evidence for non-inducing drugs was limited, and results with levetiracetam were variable.
The combination is common in older adults with atrial fibrillation and epilepsy, often after a stroke. The safest options are to avoid the inducer or to use an anticoagulant that can be monitored.
- Carbamazepine, phenobarbital, primidone and oxcarbazepine were most often involved.
- Rivaroxaban and apixaban were the most frequently reported DOACs.
- Several patients had thromboembolic events despite doubled DOAC doses.
- Levetiracetam and valproate data were sparse and inconsistent.
- Involve neurology early: switching to a non-inducing antiseizure drug may be the safest route.
Why it matters
Doubling the DOAC dose, a common workaround, did not prevent strokes and clots in several reported cases.
Don't overread it
The evidence is case reports and small observational series, prone to publication bias; the size of the risk is unknown.
The statistics, in plain English
Case reports show that a failure can happen, not how often. Publication bias means the true rate may be lower than these reports suggest, but the direction is consistent with known pharmacology.
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