seizure breakthrough
2 interactions related to seizure breakthrough
phenytoin + st. john's wort
St. John's Wort is a potent inducer of CYP3A4, CYP2C9, CYP2C19, and P-glycoprotein via activation of the pregnane X receptor. Because phenytoin is heavily metabolized by CYP2C9 and CYP2C19, concurrent St. John's Wort can lower phenytoin plasma concentrations into the subtherapeutic range, increasing the risk of breakthrough seizures.
phenytoin + ginkgo
Ginkgo biloba induces CYP2C19, the primary enzyme responsible for phenytoin metabolism. A published case report described a fatal breakthrough seizure in a patient on phenytoin and valproate whose autopsy revealed subtherapeutic anticonvulsant levels and self-administration of ginkgo biloba. Ginkgo also has independent pro-convulsant potential at high doses and through ginkgotoxin contamination.