Drug interactions
L-tryptophan + Venlafaxine
Severity: Major
L-tryptophan and Venlafaxine: major 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
L-tryptophan is a precursor of serotonin, and taking it with venlafaxine can excessively increase serotonergic activity. Cases of serotonin syndrome have been reported with tryptophan and antidepressants.
What this interaction means in plain words
L-tryptophan and Venlafaxine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Why it happens
Additive serotonergic effects from increased serotonin synthesis and reduced reuptake.
What to do
Avoid tryptophan supplements in patients taking venlafaxine. If combined, monitor for signs of serotonin syndrome.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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Other interactions of Venlafaxine
- Isocarboxazid + Venlafaxine Contraindicated
- Methylene blue + Venlafaxine Contraindicated
- Phenelzine + Venlafaxine Contraindicated
- Procarbazine + Venlafaxine Contraindicated
- Rasagiline + Venlafaxine Contraindicated
- Safinamide + Venlafaxine Contraindicated
Frequently asked questions
Can I take L-tryptophan with Venlafaxine?
MediHelp rates the interaction as major. L-tryptophan and Venlafaxine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. L-tryptophan is a precursor of serotonin, and taking it with venlafaxine can excessively increase serotonergic activity. Cases of serotonin syndrome have been reported with tryptophan and antidepressants.
How serious is the interaction between L-tryptophan and Venlafaxine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid tryptophan supplements in patients taking venlafaxine. If combined, monitor for signs of serotonin syndrome.
What other medicines interact with Venlafaxine?
MediHelp also lists interactions of Venlafaxine with, for example, Isocarboxazid, Methylene blue, Phenelzine. The full list is on the Venlafaxine page.
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