Drug interactions
L-tryptophan + Lithium
Severity: Moderate
L-tryptophan 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
Tryptophan is a serotonin precursor and lithium enhances serotonergic function. Together they have been associated with serotonin syndrome in case reports.
What this interaction means in plain words
L-tryptophan 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.
Why it happens
Additive serotonergic effects from increased serotonin synthesis and enhanced serotonergic transmission.
What to do
Avoid unnecessary use of tryptophan supplements in patients taking lithium. If used, monitor for signs of serotonin toxicity and stop tryptophan if they appear.
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 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 L-tryptophan with Lithium?
MediHelp rates the interaction as moderate. L-tryptophan 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. Tryptophan is a serotonin precursor and lithium enhances serotonergic function. Together they have been associated with serotonin syndrome in case reports.
How serious is the interaction between L-tryptophan 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: Avoid unnecessary use of tryptophan supplements in patients taking lithium. If used, monitor for signs of serotonin toxicity and stop tryptophan if they appear.
What other medicines interact with Lithium?
MediHelp also lists interactions of Lithium with, for example, Thioridazine, Vandetanib, Aceclofenac. The full list is on the Lithium page.
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