Seizure medications

Anticonvulsants and pharmacogenetics

Also known as: Antiepileptics, Seizure medications

4 medications 5 brand products CYP2C9CYP2C19

Which anticonvulsant fits my genetics best?

Depending on your genotype, these 3 medications split into up to 3 groups, from take-as-directed through to worth avoiding. Gene2Rx Pro reads CYP2C19 and CYP2C9 from your own report and tells you which is which.

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Why pharmacogenetics matter for anticonvulsants

Anticonvulsants treat epilepsy, bipolar disorder, trigeminal neuralgia, and neuropathic pain. The most consequential pharmacogenetic signal in this class is not about metabolism but about hypersensitivity: HLA-B*15:02 carriers have a dramatically elevated risk of Stevens-Johnson syndrome on carbamazepine and oxcarbazepine, and the FDA recommends pre-treatment screening in at-risk populations.^[1] Phenytoin and fosphenytoin also have CYP2C9-related dose considerations.^[2]

HLA-B*15:02 is common in people of East and Southeast Asian descent and rare elsewhere. Many US health systems now screen automatically when carbamazepine is ordered for patients from these populations. Gene2Rx does not test HLA-B*15:02; it is offered as a separate clinical test. Gene2Rx does report the CYP2C9 variants relevant to phenytoin and fosphenytoin dosing.^[3]

Key genes in this class

CYP2C9

Cytochrome P450 2C9

CYP2C9 metabolizes warfarin, phenytoin, celecoxib, and some NSAIDs. Variants that reduce its activity are most consequential for warfarin, where even small changes in drug clearance translate into very different doses …

CYP2C19

Cytochrome P450 2C19

CYP2C19 handles several SSRIs (citalopram, escitalopram, sertraline), proton pump inhibitors (omeprazole, esomeprazole), and the blood thinner clopidogrel. About 2 to 5 percent of people of European descent and 15 to …

Medications in this class with pharmacogenetic guidelines

Each link goes to the drug's full pharmacogenetics page with CPIC and FDA phenotype recommendations.

Brivaracetam CYP2C19 Clobazam CYP2C19 Fosphenytoin CYP2C9 Phenytoin CYP2C9

Brand products in the Seizure medications class

Combined products and brand names for the medications above. Each links to a pharmacogenetic breakdown.

References

U.S. Food and Drug Administration. Table of Pharmacogenetic Associations (2024). fda.gov
U.S. Food and Drug Administration. Table of Pharmacogenomic Biomarkers in Drug Labeling (2024). fda.gov
PharmGKB / Stanford University. PharmGKB: The Pharmacogenomics Knowledge Base. pharmgkb.org

Which seizure medications is right for your genetics?

This page covers the pharmacogenetics of anticonvulsants in general. A Gene2Rx report tells you how your personal genotype interacts with every drug on this page.

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Informational only, not medical advice. Pharmacogenetic guidelines describe population-level patterns that inform prescribing decisions. Never start, stop, or change a medication without talking to your prescribing clinician.