Phenytoin and Phytonadione (vitamin K1) interaction
Phenytoin and Phytonadione (vitamin K1): the Phenytoin prescribing label flag 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 Phenytoin label · effective 2024-12-24
A potentially life-threatening bleeding disorder related to decreased levels of vitamin K-dependent clotting factors may occur in newborns exposed to phenytoin in utero.
This drug-induced condition can be prevented with vitamin K administration to the mother before delivery and to the neonate after birth.
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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.