Lithium and Phenytoin interaction
Lithium and Phenytoin: the Lithium 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 Lithium (Lithium Carbonate) label · effective 2026-06-04
Methyldopa, Phenytoin and Carbamazepine Clinical Impact: Concomitant use may increase risk of adverse reactions of these drugs.
Intervention: Monitor patients closely for adverse reactions of methyldopa, phenytoin, and carbamazepine.
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.