Drug interactions
Dextromethorphan + Trifluoperazine
Severity: Moderate
Dextromethorphan and Trifluoperazine: 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
Trifluoperazine, a phenothiazine, may modestly inhibit CYP2D6 and has dopamine-blocking effects, while dextromethorphan is serotonergic and a CYP2D6 substrate. Serotonin toxicity or neuroleptic-type reactions are theoretically possible and dextromethorphan exposure may increase.
What this interaction means in plain words
Dextromethorphan and Trifluoperazine 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.
Why it happens
Additive serotonergic and dopaminergic modulation, with possible CYP2D6 competition.
What to do
Monitor for mental status change, hyperthermia, rigidity and sedation when starting or increasing either drug. Use the lowest effective dextromethorphan dose.
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 Dextromethorphan
- Dextromethorphan + Isocarboxazid Contraindicated
- Dextromethorphan + Linezolid Contraindicated
- Dextromethorphan + Phenelzine Contraindicated
- Dextromethorphan + Rasagiline Contraindicated
- Dextromethorphan + Safinamide Contraindicated
- Dextromethorphan + Selegiline Contraindicated
Frequently asked questions
Can I take Dextromethorphan with Trifluoperazine?
MediHelp rates the interaction as moderate. Dextromethorphan and Trifluoperazine 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. Trifluoperazine, a phenothiazine, may modestly inhibit CYP2D6 and has dopamine-blocking effects, while dextromethorphan is serotonergic and a CYP2D6 substrate. Serotonin toxicity or neuroleptic-type reactions are theoretically possible and dextromethorphan exposure may increase.
How serious is the interaction between Dextromethorphan and Trifluoperazine?
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 mental status change, hyperthermia, rigidity and sedation when starting or increasing either drug. Use the lowest effective dextromethorphan dose.
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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