Drug interactions
Clomipramine + Dextromethorphan
Severity: Major
Clomipramine and Dextromethorphan: major interaction.
Last updated Sources: UK SmPC
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
Clomipramine is strongly serotonergic, and adding dextromethorphan may precipitate serotonin syndrome. Clomipramine metabolites may also inhibit CYP2D6 and raise dextromethorphan levels.
What this interaction means in plain words
Clomipramine and Dextromethorphan can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Clomipramine belongs to Central Nervous System; Dextromethorphan belongs to Respiratory.
Why it happens
Additive serotonergic effects with CYP2D6-mediated reduction of dextromethorphan metabolism.
What to do
Avoid the combination and use a non-serotonergic antitussive. If unavoidable, use minimal doses and monitor for serotonin toxicity.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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References
- Benylin Dry Coughs 7.5mg / 5ml Syrup - SmPC sections 4.3/4.5 (class statement: psychotropics; "Dextromethorphan might exhibit additive CNS depressant effects when co-administered with alcohol, antihistamines, psychotropics, and other CNS depressant drugs.") — electronic medicines compendium (UK SmPC)
Other interactions of Dextromethorphan
- Dextromethorphan + Isocarboxazid Contraindicated
- Dextromethorphan + Linezolid Contraindicated
- Dextromethorphan + Phenelzine Contraindicated
- Dextromethorphan + Rasagiline Contraindicated
- Dextromethorphan + Safinamide Contraindicated
- Dextromethorphan + Selegiline Contraindicated
Other interactions of Clomipramine
- Arsenic trioxide + Clomipramine Contraindicated
- Clomipramine + Dofetilide Contraindicated
- Clomipramine + Droperidol Contraindicated
- Clomipramine + Isocarboxazid Contraindicated
- Clomipramine + Methylene blue Contraindicated
- Clomipramine + Pentamidine Contraindicated
Frequently asked questions
Can I take Clomipramine with Dextromethorphan?
MediHelp rates the interaction as major. Clomipramine and Dextromethorphan can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Clomipramine is strongly serotonergic, and adding dextromethorphan may precipitate serotonin syndrome. Clomipramine metabolites may also inhibit CYP2D6 and raise dextromethorphan levels.
How serious is the interaction between Clomipramine and Dextromethorphan?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination and use a non-serotonergic antitussive. If unavoidable, use minimal doses and monitor for serotonin toxicity.
What other medicines interact with Dextromethorphan?
MediHelp also lists interactions of Dextromethorphan with, for example, Isocarboxazid, Linezolid, Phenelzine. The full list is on the Dextromethorphan page.
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