Moderate
Established
Mô tả
Phenytoin reduces topiramate plasma levels via enzyme induction, potentially compromising seizure control when topiramate is added to phenytoin therapy.
Cơ chế
Phenytoin is a potent CYP3A4 and CYP2C19 inducer that increases topiramate metabolic clearance by approximately 48%.
Ý nghĩa lâm sàng
Topiramate levels may be halved by phenytoin co-administration; dose adjustments are typically required to maintain therapeutic effect.
Xử trí
Monitor seizure control and topiramate levels; titrate topiramate to therapeutic effect with awareness of enhanced clearance.