Drug interactions
Dextromethorphan + L-tryptophan
Severity: Moderate
Dextromethorphan and L-tryptophan: 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
Tryptophan is a serotonin precursor, and with a serotonergic drug such as dextromethorphan it may raise the risk of serotonin syndrome. Cases are mostly reported with other serotonergic agents.
What this interaction means in plain words
Dextromethorphan and L-tryptophan 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 effect from increased serotonin synthesis and dextromethorphan's reuptake inhibition.
What to do
Monitor for signs of serotonin toxicity such as agitation, tremor and hyperthermia, especially with high doses of either agent.
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 L-tryptophan?
MediHelp rates the interaction as moderate. Dextromethorphan and L-tryptophan 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. Tryptophan is a serotonin precursor, and with a serotonergic drug such as dextromethorphan it may raise the risk of serotonin syndrome. Cases are mostly reported with other serotonergic agents.
How serious is the interaction between Dextromethorphan and L-tryptophan?
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 signs of serotonin toxicity such as agitation, tremor and hyperthermia, especially with high doses of either agent.
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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