Genetic factors contribute to the high inter-individual variability in response to anti-epileptic drugs.
Many medications, including the majority of anti-epileptic medications, are metabolized by two enzymes in the liver: CYP2C9 and CYP2C19.
Other metabolic pathways include CYP3A4, CYP3A5, HLA-B*15:02, HLA-A*31:01 and UGT1A1.
Your genes are the main factor determining the level of these enzymes found primarily in your liver.
Population Frequency of Cytochrome P450 (CYP) Metabolizer Types [5]
| Poor (no or low enzyme levels) |
Intermediate (reduced enzyme levels) |
Normal (normal enzyme levels) |
|
|---|---|---|---|
| CYP2C9 | 3% | 30% | 68% |
| CYP2C19* | 3%-21% | 24-36% | 79-97% |
*CYP2C19 variability depends on ethnicity.
Some epilepsy medications that are impacted by your genetics: [12]
| Trade Name | DRUG |
|---|---|
| Briviact® | brivaracetam |
| Cerebyx® | fosphenytoin |
| Depakote | valproic acid |
| Dilantin® | phenytoin |
| Tegretol® | carbamazepine |
| Trileptal® | oxcarbazepine |
| Vimpat® | lacosamide |