Drug interactions
Dextromethorphan + Lithium
Severity: Moderate
Dextromethorphan and Lithium: 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
Lithium enhances serotonergic transmission, and with dextromethorphan could theoretically add to the risk of serotonin toxicity. Documented cases are few.
What this interaction means in plain words
Dextromethorphan and Lithium 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; Lithium belongs to Central Nervous System.
Why it happens
Additive serotonergic effects; lithium enhances serotonin neurotransmission while dextromethorphan inhibits serotonin reuptake.
What to do
Monitor for tremor, agitation, clonus and autonomic instability. Avoid high or prolonged dextromethorphan dosing in lithium-treated patients.
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 Lithium
- Lithium + Thioridazine Contraindicated
- Lithium + Vandetanib Contraindicated
- Aceclofenac + Lithium Major
- Acemetacin + Lithium Major
- Amisulpride + Lithium Major
- Amlodipine-benazepril + Lithium Major
Frequently asked questions
Can I take Dextromethorphan with Lithium?
MediHelp rates the interaction as moderate. Dextromethorphan and Lithium 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. Lithium enhances serotonergic transmission, and with dextromethorphan could theoretically add to the risk of serotonin toxicity. Documented cases are few.
How serious is the interaction between Dextromethorphan and Lithium?
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 tremor, agitation, clonus and autonomic instability. Avoid high or prolonged dextromethorphan dosing in lithium-treated patients.
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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