Phenytoin and Valbenazine interaction
Phenytoin and Valbenazine: both prescribing labels 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 Valbenazine (INGREZZA) label · effective 2026-04-17
Use of strong CYP3A4 inducers with INGREZZA or INGREZZA SPRINKLE Concomitant use is not recommended.
Prevention or Management: Concomitant use of strong CYP3A4 inducers with INGREZZA or INGREZZA SPRINKLE is not recommended [see Dosage and Administration ( 2.5 )].
Strong CYP3A4 Inducers Clinical Implication: Concomitant use of INGREZZA or INGREZZA SPRINKLE with a strong CYP3A4 inducer decreased the exposure of valbenazine and its active metabolite compared to the use of INGREZZA or INGREZZA SPRINKLE alone.
From the Phenytoin label · effective 2024-12-24
…Phenytoin and antacids should not be taken at the same time of day Antineoplastic agents (usually in combination) Bleomycin, carboplatin, cisplatin, doxorubicin, methotrexate Antiviral agents Fosamprenavir, nelfinavir, ritonavir Antiepileptic drugs Carbamazepine, vigabatrin Other Chronic alcohol abuse, diazepam, diazoxide, folic acid, reserpine, rifampin, 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.