Drug interactions
Phenytoin + Quizartinib
Severity: Major
Phenytoin and Quizartinib: major interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Phenytoin, a strong CYP3A4 inducer, can markedly lower quizartinib exposure and may compromise its antileukemic efficacy.
What this interaction means in plain words
Phenytoin and Quizartinib can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Phenytoin belongs to Central Nervous System; Quizartinib belongs to Oncology.
Why it happens
Phenytoin induces CYP3A4, increasing the metabolism of quizartinib and its active metabolite.
What to do
Avoid concomitant use and select a non-inducing antiseizure drug such as levetiracetam. Monitor leukemia response if the combination cannot be avoided.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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Other interactions of Phenytoin
- Artemether / lumefantrine + Phenytoin Contraindicated
- Bictegravir + Phenytoin Contraindicated
- Cabotegravir + Phenytoin Contraindicated
- Doravirine + Phenytoin Contraindicated
- Elbasvir / grazoprevir + Phenytoin Contraindicated
- Elvitegravir / cobicistat / emtricitabine / tenofovir df + Phenytoin Contraindicated
Other interactions of Quizartinib
- Quizartinib + Thioridazine Contraindicated
- Quizartinib + Ziprasidone Contraindicated
- Alfuzosin + Quizartinib Major
- Amiodarone + Quizartinib Major
- Amitriptyline + Quizartinib Major
- Amobarbital + Quizartinib Major
Frequently asked questions
Can I take Phenytoin with Quizartinib?
MediHelp rates the interaction as major. Phenytoin and Quizartinib can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Phenytoin, a strong CYP3A4 inducer, can markedly lower quizartinib exposure and may compromise its antileukemic efficacy.
How serious is the interaction between Phenytoin and Quizartinib?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid concomitant use and select a non-inducing antiseizure drug such as levetiracetam. Monitor leukemia response if the combination cannot be avoided.
What other medicines interact with Phenytoin?
MediHelp also lists interactions of Phenytoin with, for example, Artemether / lumefantrine, Bictegravir, Cabotegravir. The full list is on the Phenytoin page.
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