Drug interactions
Fluvoxamine + St john's wort
Severity: Major
Fluvoxamine and St john's wort: major interaction.
Last updated Sources: US FDA label
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
Both agents enhance serotonergic neurotransmission, so taking them together raises the risk of serotonin syndrome, with agitation, tremor, hyperthermia, diarrhea and neuromuscular hyperactivity. St John's wort may also alter the exposure of other drugs through enzyme induction.
What this interaction means in plain words
Fluvoxamine and St john's wort 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 SSRI-mediated serotonin reuptake inhibition and St John's wort's reuptake inhibition of serotonin and other monoamines.
What to do
Avoid the combination and advise patients to stop St John's wort before starting or continuing fluvoxamine. If combined exposure has occurred, monitor for serotonin toxicity symptoms.
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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References
Other interactions of Fluvoxamine
- Agomelatine + Fluvoxamine Contraindicated
- Alosetron + Fluvoxamine Contraindicated
- Fezolinetant + Fluvoxamine Contraindicated
- Fluvoxamine + Isocarboxazid Contraindicated
- Fluvoxamine + Mavacamten Contraindicated
- Fluvoxamine + Methylene blue Contraindicated
Frequently asked questions
Can I take Fluvoxamine with St john's wort?
MediHelp rates the interaction as major. Fluvoxamine and St john's wort 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. Both agents enhance serotonergic neurotransmission, so taking them together raises the risk of serotonin syndrome, with agitation, tremor, hyperthermia, diarrhea and neuromuscular hyperactivity. St John's wort may also alter the exposure of other drugs through enzyme induction.
How serious is the interaction between Fluvoxamine and St john's wort?
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 the combination and advise patients to stop St John's wort before starting or continuing fluvoxamine. If combined exposure has occurred, monitor for serotonin toxicity symptoms.
What other medicines interact with Fluvoxamine?
MediHelp also lists interactions of Fluvoxamine with, for example, Agomelatine, Alosetron, Fezolinetant. The full list is on the Fluvoxamine page.
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