Phenytoin and Toremifene interaction
Phenytoin and Toremifene: the Toremifene prescribing label flags this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Toremifene (Fareston) label · effective 2024-11-13
Coadministration with a strong CYP3A4 inducer may result in a relevant decrease in FARESTON exposure and should be avoided.
CYP2C9 substrates with a narrow therapeutic index such as warfarin or phenytoin with FARESTON should be used with caution and require careful monitoring.
Concomitant use of CYP2C9 substrates with a narrow therapeutic index such as warfarin or phenytoin with FARESTON should be done with caution and requires careful monitoring (e.g., substrate concentrations (if possible), appropriate laboratory markers, and signs and symptoms of increased exposure).
Effect of Strong CYP3A4 Inducers on Toremifene Strong CYP3A4 enzyme inducers, such as dexamethasone, phenytoin, carbamazepine, rifampin, rifabutin, phenobarbital, St.
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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.