Drug interactions
Chloroquine + Phenytoin
Severity: Moderate
Chloroquine and Phenytoin: moderate 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 induces hepatic enzymes and may lower chloroquine concentrations, potentially reducing antimalarial or antirheumatic efficacy. The clinical significance is not well quantified.
What this interaction means in plain words
Chloroquine and Phenytoin can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Chloroquine belongs to Anti Parasitic; Phenytoin belongs to Central Nervous System.
Why it happens
Enzyme induction by phenytoin (including CYP3A4) increases chloroquine metabolism.
What to do
Monitor for reduced chloroquine response, particularly when used for malaria treatment or prophylaxis. Consider an alternative antimalarial if efficacy is a concern.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Chloroquine
- Chloroquine + Cisapride Contraindicated
- Chloroquine + Dofetilide Contraindicated
- Chloroquine + Dronedarone Contraindicated
- Chloroquine + Droperidol Contraindicated
- Chloroquine + Panobinostat Contraindicated
- Chloroquine + Pimozide Contraindicated
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
Frequently asked questions
Can I take Chloroquine with Phenytoin?
MediHelp rates the interaction as moderate. Chloroquine and Phenytoin can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Phenytoin induces hepatic enzymes and may lower chloroquine concentrations, potentially reducing antimalarial or antirheumatic efficacy. The clinical significance is not well quantified.
How serious is the interaction between Chloroquine and Phenytoin?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor for reduced chloroquine response, particularly when used for malaria treatment or prophylaxis. Consider an alternative antimalarial if efficacy is a concern.
What other medicines interact with Chloroquine?
MediHelp also lists interactions of Chloroquine with, for example, Cisapride, Dofetilide, Dronedarone. The full list is on the Chloroquine page.
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