Drug interactions
Citalopram + Phenytoin
Severity: Moderate
Citalopram 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 several CYP enzymes, including CYP3A4 and CYP2C19, and may lower citalopram concentrations and reduce its efficacy. Citalopram may also occasionally alter phenytoin levels.
What this interaction means in plain words
Citalopram 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.
Citalopram belongs to Central Nervous System; Phenytoin belongs to Central Nervous System.
Why it happens
Phenytoin induces CYP3A4 and CYP2C19, increasing citalopram clearance.
What to do
Monitor for loss of antidepressant response and adjust the citalopram dose within the labeled maximum. Monitor phenytoin concentrations when starting or stopping citalopram.
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 Citalopram
- Cisapride + Citalopram Contraindicated
- Citalopram + Dronedarone Contraindicated
- Citalopram + Escitalopram Contraindicated
- Citalopram + Isocarboxazid Contraindicated
- Citalopram + Methylene blue Contraindicated
- Citalopram + Phenelzine 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 Citalopram with Phenytoin?
MediHelp rates the interaction as moderate. Citalopram 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 several CYP enzymes, including CYP3A4 and CYP2C19, and may lower citalopram concentrations and reduce its efficacy. Citalopram may also occasionally alter phenytoin levels.
How serious is the interaction between Citalopram 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 loss of antidepressant response and adjust the citalopram dose within the labeled maximum. Monitor phenytoin concentrations when starting or stopping citalopram.
What other medicines interact with Citalopram?
MediHelp also lists interactions of Citalopram with, for example, Cisapride, Dronedarone, Escitalopram. The full list is on the Citalopram page.
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