Nefazodone and Phenytoin interaction
Nefazodone and Phenytoin: 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 Nefazodone (Nefazodone Hydrochloride) label · effective 2025-07-31
However, due to the nonlinear pharmacokinetics of phenytoin, the failure to observe a significant effect on the single-dose pharmacokinetics of phenytoin does not preclude the possibility of a clinically significant interaction with nefazodone when phenytoin is dosed chronically.
However, no change in the initial dosage of phenytoin is considered necessary and any subsequent adjustment of phenytoin dosage should be guided by usual clinical practices.
Phenytoin – Pretreatment for 7 days with 200 mg BID of nefazodone had no effect on the pharmacokinetics of a single 300 mg oral dose of phenytoin.
From the Phenytoin label · effective 2024-12-24
…Ethosuximide, felbamate, oxcarbazepine, methsuximide, topiramate Azoles Fluconazole, ketoconazole, itraconazole, miconazole, voriconazole Antineoplastic agents Capecitabine, fluorouracil Antidepressants Fluoxetine, fluvoxamine, sertraline Gastric acid reducing agents H 2 antagonists (cimetidine), omeprazole Sulfonamides Sulfamethizole, sulfaphenazole, sulfadiazine,…
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.