Drug interactions
Clopidogrel + Phenytoin
Severity: Moderate
Clopidogrel 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 CYP enzymes and may increase formation of clopidogrel's active metabolite, potentially enhancing platelet inhibition. Conversely, clopidogrel may inhibit CYP2C9 and raise phenytoin levels.
What this interaction means in plain words
Clopidogrel 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.
Clopidogrel belongs to Cardiovascular; Phenytoin belongs to Central Nervous System.
Why it happens
Enzyme induction by phenytoin may increase clopidogrel bioactivation, and clopidogrel's metabolite may inhibit CYP2C9-mediated phenytoin metabolism.
What to do
Monitor for bleeding and check phenytoin concentrations when starting or stopping clopidogrel. Adjust the phenytoin dose according to levels and clinical signs of toxicity.
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 Clopidogrel
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 Clopidogrel with Phenytoin?
MediHelp rates the interaction as moderate. Clopidogrel 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 CYP enzymes and may increase formation of clopidogrel's active metabolite, potentially enhancing platelet inhibition. Conversely, clopidogrel may inhibit CYP2C9 and raise phenytoin levels.
How serious is the interaction between Clopidogrel 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 bleeding and check phenytoin concentrations when starting or stopping clopidogrel. Adjust the phenytoin dose according to levels and clinical signs of toxicity.
What other medicines interact with Clopidogrel?
MediHelp also lists interactions of Clopidogrel with, for example, Ombitasvir / paritaprevir / ritonavir and dasabuvir, Abrocitinib, Acetylsalicylic acid. The full list is on the Clopidogrel page.
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