Drug interactions
Phenytoin + Trimipramine
Severity: Moderate
Phenytoin and Trimipramine: 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 is a hepatic enzyme inducer and may lower trimipramine exposure, reducing antidepressant efficacy. Tricyclics can also lower the seizure threshold, which may reduce seizure control in patients taking phenytoin.
What this interaction means in plain words
Phenytoin and Trimipramine 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 belongs to Central Nervous System; Trimipramine belongs to Central Nervous System.
Why it happens
Phenytoin induces hepatic CYP enzymes (including CYP3A4 and CYP2C), increasing trimipramine clearance; trimipramine also lowers seizure threshold.
What to do
Monitor depressive symptoms and seizure frequency, and consider trimipramine dose adjustment guided by clinical response or drug levels. Check phenytoin levels if seizure control changes.
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 Trimipramine
- Disopyramide + Trimipramine Contraindicated
- Dofetilide + Trimipramine Contraindicated
- Ibutilide + Trimipramine Contraindicated
- Isocarboxazid + Trimipramine Contraindicated
- Pentamidine + Trimipramine Contraindicated
- Phenelzine + Trimipramine 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 Phenytoin with Trimipramine?
MediHelp rates the interaction as moderate. Phenytoin and Trimipramine 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 is a hepatic enzyme inducer and may lower trimipramine exposure, reducing antidepressant efficacy. Tricyclics can also lower the seizure threshold, which may reduce seizure control in patients taking phenytoin.
How serious is the interaction between Phenytoin and Trimipramine?
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 depressive symptoms and seizure frequency, and consider trimipramine dose adjustment guided by clinical response or drug levels. Check phenytoin levels if seizure control changes.
What other medicines interact with Trimipramine?
MediHelp also lists interactions of Trimipramine with, for example, Disopyramide, Dofetilide, Ibutilide. The full list is on the Trimipramine page.
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