Page Banner
Mayo Clinic Laboratories > Therapeutics > Precision therapeutics > Precision mental and behavioral health therapeutics > Precision epilepsy therapeutics

Precision epilepsy therapeutics

Precise answers to guide treatment selection and measure efficacy

For patients affected by epilepsy, finding the right medication or combination of medications to achieve stable seizure control can be a lifelong challenge. Multiple factors, such as genetic variation, aging, pregnancy, and patient compliance, can affect medication metabolization and impact treatment response.

A precision medicine approach that integrates pharmacogenomic (PGx) testing and therapeutic drug monitoring (TDM) is integral for ensuring safe and effective antiseizure therapy. This approach is especially important for patients with drug-resistant epilepsy (DRE) who require higher medication amounts to control seizure activity. In these cases, TDM helps quantify whether medication concentrations remain within the individual’s therapeutic range, which can often be outside of standard therapeutic ranges. Results from PGx and TDM can also inform additional diagnostic testing, especially in DRE cases that lack an underlying etiology.

Mayo Clinic Laboratories’ comprehensive menu of PGx and TDM assays is a singular, end-to-end solution for accurate, patient-specific answers across a patient’s treatment journey.

30–40%

30–40% of patients with epilepsy have seizures that are not controlled by medicine1

Precision epilepsy test menu

Pharmacogenomic medication-targeted testing Pharmacogenomic medication-targeted testing
Therapeutic drug monitoring for anti-seizure medications Therapeutic drug monitoring for anti-seizure medications

Pharmacogenomic, medication-targeted testing

Prior to therapy initiation, PGx testing can identify genetic variations that impact a patient’s ability to metabolize a particular medication. Our pharmacogenomic portfolio evaluates clinically actionable drug-gene interactions to guide safe and effective antiseizure therapy. Key associations identified through our testing include:

  • HLA-B15:02 / HLA-A31:01 andhypersensitivity risk with carbamazepine and oxcarbazepine.2
  • CYP2C9 and reduced phenytoin metabolism and dose-dependent toxicity.3

Each result includes Clinical Pharmacogenetics Implementation Consortium (CPIC)-aligned prescribing guidance with clear recommendations for dose adjustment or alternate therapy to minimize adverse drug reactions and optimize seizure control.

Key testing

  • CARBR | Carbamazepine Hypersensitivity Pharmacogenomics, Varies
    • Identifies individuals with specific human leukocyte antigen (HLA) alleles associated with the development of certain cutaneous adverse reactions to aromatic anticonvulsants.
    • Genotyping of HLA-B*15:02, which is strongly associated with a greater risk of Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) in patients treated with carbamazepine or oxcarbazepine.
      • Individuals who are positive for HLA-B*15:02 should also avoid phenytoin and fosphenytoin due to the association with hypersensitivity risk. Other aromatic antiepileptics, including eslicarbazepine, lamotrigine, and phenobarbital, have weaker evidence linking HLA-B*15:02 allele to hypersensitivity, but caution should be exercised when selecting an alternative agent.4
    • Genotyping of HLA-A*31:01, which is associated with increased risk of maculopapular exanthema, drug reaction with eosinophilia and systemic symptoms, and SJS/TEN in patients treated with carbamazepine.
  • PSYQP | Psychotropic Pharmacogenomics Gene Panel, Varies
    • Examines 23 genes (141 alleles) used to assess approximately 80 medications. 
    • Identifies variations in genes known to be associated with response and/or risk of toxicity with psychotropic medications. 

Therapeutic drug monitoring for anti-seizure medications

For epilepsy patients, high-dose treatment protocols are common. Access to broad analytical ranges is critical to ensure accurate measurement of medication concentrations, even when drug levels exceed typical thresholds.5,6 Our TDM assays use advanced analytical technologies, including high-performance liquid chromatography tandem mass spectrometry, where appropriate, to accurately measure medication concentrations in a patient’s blood and feature broad analytical ranges that can quantify high concentrations of anti-seizure medications.

Because most of our tests provide next-day answers on a wide range of medications, clinicians can make expeditious clinical decisions based on data reflective of the patient’s true exposure. Interpretive result reporting by testing experts ensures each result is reported in the context of each patient’s unique treatment scenario.

Key testing

Learn more View our menu of neurology epilepsy testing

Additional tests

Carbamazepine

Ethosuximide

Felbatol

Lacosamide

Oxcarbazepine

Phenytoin

Pregabalin

Primidone and Phenobarbital

Rufinamide

Topiramate

Trimethoprim

Valproic Acid

Zonisamide

References
  1. Engel J Jr. Approaches to refractory epilepsy. Ann Indian Acad Neurol. 2014 Mar;17(Suppl 1):S12-7. doi:10.4103/0972-2327.128644. PMID: 24791078; PMCID: PMC4001229.
  2. Clinical Pharmacogenetics Implementation Consortium (CPIC). Guideline for Carbamazepine and HLA-B15:02 and HLA-A31:01. Updated 2024. https://cpicpgx.org/guidelines/guideline-for-carbamazepine-and-hla-b/
  3. CPIC. Guideline for Phenytoin and CYP2C9 and HLA-B15:02.* Updated 2024. https://cpicpgx.org/guidelines/guideline-for-phenytoin-and-cyp2c9-and-hla-b/.
  4. Caudle KE, Sangkuhl K, Whirl-Carrillo M, et al. Clinical Pharmacogenetics Implementation Consortium Guideline for CYP2C9 and HLA-B Genotypes and Phenytoin Dosing. Clin Pharmacol Ther. 2020;108(5):865-876. doi:10.1002/cpt.1903
  5. Hiemke C, Bergemann N, Clement HW, et al. Consensus guidelines for therapeutic drug monitoring in neuropsychopharmacology: Update 2017. Pharmacopsychiatry. 2018;51(1-02):e1. doi:10.1055/s-0037-1600991
  6. Patsalos PN, Spencer EP, Berry DJ. Therapeutic drug monitoring of antiepileptic drugs in epilepsy: Updated guidelines from the ILAE TDM Task Force. Ther Drug Monit. 2022;44(5):621-646. doi:10.1097/FTD.0000000000000989
INTERESTED IN LEARNING MORE?

Fill out the form below and one of our specialists will be in touch.

Are you a patient? Click here.