Fosphenytoin and Mexiletine interaction
Fosphenytoin and Mexiletine: both prescribing labels describe an interaction that usually calls for monitoring, a dose change, or spacing the doses.
Usually manageable with monitoring or a dose change. Tell your pharmacist you take both.
What the FDA labels say
From the Fosphenytoin (CEREBYX) label · effective 2025-08-28
…Nifedipine, nimodipine, nisoldipine, verapamil Other Albendazole (decreases active metabolite), chlorpropamide, clozapine, cyclosporine, digoxin, disopyramide, folic acid, methadone, mexiletine, praziquantel, quetiapine 7.3 Hyperammonemia with Concomitant Use of Valproate Concomitant administration of phenytoin and valproate has been associated with an increased…
From the Mexiletine (Mexiletine Hydrochloride) label · effective 2026-01-15
When phenytoin or other hepatic enzyme inducers such as rifampin and phenobarbital have been taken concurrently with mexiletine, lowered mexiletine plasma levels have been reported.
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.