Drug interactions
Clomipramine + Fosphenytoin
Severity: Moderate
Clomipramine and Fosphenytoin: 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
Fosphenytoin is converted to phenytoin, an inducer of hepatic enzymes, which may lower clomipramine concentrations and reduce antidepressant efficacy. Tricyclics can also lower the seizure threshold and occasionally alter phenytoin levels, complicating seizure control.
What this interaction means in plain words
Clomipramine and Fosphenytoin 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.
Clomipramine belongs to Central Nervous System; Fosphenytoin belongs to Central Nervous System.
Why it happens
Phenytoin induces CYP enzymes (including CYP3A4 and CYP2C19) that metabolize clomipramine, and tricyclics have proconvulsant activity.
What to do
Monitor depressive or obsessive symptoms and consider raising clomipramine dose guided by clinical response or plasma levels. Monitor phenytoin levels and seizure control.
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 Clomipramine
- Arsenic trioxide + Clomipramine Contraindicated
- Clomipramine + Dofetilide Contraindicated
- Clomipramine + Droperidol Contraindicated
- Clomipramine + Isocarboxazid Contraindicated
- Clomipramine + Methylene blue Contraindicated
- Clomipramine + Pentamidine Contraindicated
Other interactions of Fosphenytoin
- Dronedarone + Fosphenytoin Contraindicated
- Fosphenytoin + Ledipasvir-sofosbuvir Contraindicated
- Fosphenytoin + Lorlatinib Contraindicated
- Fosphenytoin + Lurasidone Contraindicated
- Fosphenytoin + Ranolazine Contraindicated
- Fosphenytoin + Sofosbuvir-velpatasvir-voxilaprevir Contraindicated
Frequently asked questions
Can I take Clomipramine with Fosphenytoin?
MediHelp rates the interaction as moderate. Clomipramine and Fosphenytoin 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. Fosphenytoin is converted to phenytoin, an inducer of hepatic enzymes, which may lower clomipramine concentrations and reduce antidepressant efficacy. Tricyclics can also lower the seizure threshold and occasionally alter phenytoin levels, complicating seizure control.
How serious is the interaction between Clomipramine and Fosphenytoin?
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 or obsessive symptoms and consider raising clomipramine dose guided by clinical response or plasma levels. Monitor phenytoin levels and seizure control.
What other medicines interact with Clomipramine?
MediHelp also lists interactions of Clomipramine with, for example, Arsenic trioxide, Dofetilide, Droperidol. The full list is on the Clomipramine page.
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