Modafinil and Phenytoin interaction
Modafinil and Phenytoin: the Modafinil prescribing label 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 Modafinil (Provigil) label · effective 2025-10-16
Effects of PROVIGIL on CYP2C19 Substrates Elimination of drugs that are substrates for CYP2C19 (e.g., phenytoin, diazepam, propranolol, omeprazole, and clomipramine) may be prolonged by PROVIGIL via inhibition of metabolic enzymes, with resultant higher systemic exposure.
CYP2C19 substrates, such as omeprazole, phenytoin, and diazepam: Exposure of these medications may be increased.
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.