Drug interactions
Lithium + St john's wort
Severity: Moderate
Lithium and St john's wort: 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
St John's wort has serotonergic activity and combining it with lithium may increase the risk of serotonin syndrome. Case reports describe serotonergic toxicity with this type of combination.
What this interaction means in plain words
Lithium and St john's wort 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, with St John's wort inhibiting reuptake of serotonin and other monoamines.
What to do
Advise patients to avoid St John's wort while on lithium. If it has been used, monitor for signs of serotonin toxicity.
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 Lithium with St john's wort?
MediHelp rates the interaction as moderate. Lithium and St john's wort 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. St John's wort has serotonergic activity and combining it with lithium may increase the risk of serotonin syndrome. Case reports describe serotonergic toxicity with this type of combination.
How serious is the interaction between Lithium and St john's wort?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Advise patients to avoid St John's wort while on lithium. If it has been used, monitor for signs of serotonin toxicity.
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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