Drug interactions
Dextromethorphan + Doxepin
Severity: Moderate
Dextromethorphan and Doxepin: 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
Both drugs have serotonergic activity, and doxepin is a CYP2D6 substrate and weak inhibitor, which may increase dextromethorphan exposure. The combination may raise the risk of serotonin syndrome.
What this interaction means in plain words
Dextromethorphan and Doxepin 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.
Dextromethorphan belongs to Respiratory; Doxepin belongs to Dermatology.
Why it happens
Additive serotonergic effects, with possible reduced CYP2D6 metabolism of dextromethorphan.
What to do
Prefer a non-serotonergic antitussive. If both are used, keep the dextromethorphan dose low and monitor for agitation, tremor and hyperthermia.
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
Other interactions of Doxepin
- Doxepin + Isocarboxazid Contraindicated
- Doxepin + Phenelzine Contraindicated
- Doxepin + Procarbazine Contraindicated
- Doxepin + Safinamide Contraindicated
- Doxepin + Selegiline Contraindicated
- Doxepin + Tranylcypromine Contraindicated
Frequently asked questions
Can I take Dextromethorphan with Doxepin?
MediHelp rates the interaction as moderate. Dextromethorphan and Doxepin 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. Both drugs have serotonergic activity, and doxepin is a CYP2D6 substrate and weak inhibitor, which may increase dextromethorphan exposure. The combination may raise the risk of serotonin syndrome.
How serious is the interaction between Dextromethorphan and Doxepin?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Prefer a non-serotonergic antitussive. If both are used, keep the dextromethorphan dose low and monitor for agitation, tremor and hyperthermia.
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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