Drug interactions
Imipramine + Phenytoin
Severity: Moderate
Imipramine 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 can lower imipramine concentrations, reducing antidepressant effect. Tricyclics may in turn raise phenytoin levels in some patients and can lower seizure threshold, while both add to CNS depression.
What this interaction means in plain words
Imipramine 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.
Imipramine belongs to Central Nervous System; Phenytoin belongs to Central Nervous System.
Why it happens
Phenytoin induction of CYP enzymes increases imipramine clearance, and tricyclics may inhibit phenytoin metabolism.
What to do
Monitor antidepressant response and consider tricyclic level monitoring, adjusting the imipramine dose. Check phenytoin levels when a tricyclic is started or if toxicity signs appear.
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 Imipramine
- Dronedarone + Imipramine Contraindicated
- Imipramine + Isocarboxazid Contraindicated
- Imipramine + Phenelzine Contraindicated
- Imipramine + Pimozide Contraindicated
- Imipramine + Rasagiline Contraindicated
- Imipramine + Safinamide 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 Imipramine with Phenytoin?
MediHelp rates the interaction as moderate. Imipramine 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 can lower imipramine concentrations, reducing antidepressant effect. Tricyclics may in turn raise phenytoin levels in some patients and can lower seizure threshold, while both add to CNS depression.
How serious is the interaction between Imipramine 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 antidepressant response and consider tricyclic level monitoring, adjusting the imipramine dose. Check phenytoin levels when a tricyclic is started or if toxicity signs appear.
What other medicines interact with Imipramine?
MediHelp also lists interactions of Imipramine with, for example, Dronedarone, Isocarboxazid, Phenelzine. The full list is on the Imipramine page.
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