Drug interactions
Meperidine + St john's wort
Severity: Major
Meperidine and St john's wort: 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
St John's wort has serotonergic activity and may add to meperidine's serotonergic effects, raising the risk of serotonin syndrome. It also induces CYP3A4, which may shift meperidine metabolism toward neurotoxic normeperidine.
What this interaction means in plain words
Meperidine 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 serotonin reuptake inhibition, with CYP3A4 induction possibly increasing normeperidine formation.
What to do
Avoid combination and use a non-serotonergic opioid; if used, monitor for 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 Meperidine
- Alvimopan + Meperidine Contraindicated
- Isocarboxazid + Meperidine Contraindicated
- Meperidine + Methylene blue Contraindicated
- Meperidine + Olanzapine / samidorphan Contraindicated
- Meperidine + Phenelzine Contraindicated
- Meperidine + Procarbazine Contraindicated
Frequently asked questions
Can I take Meperidine with St john's wort?
MediHelp rates the interaction as major. Meperidine 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. St John's wort has serotonergic activity and may add to meperidine's serotonergic effects, raising the risk of serotonin syndrome. It also induces CYP3A4, which may shift meperidine metabolism toward neurotoxic normeperidine.
How serious is the interaction between Meperidine 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 combination and use a non-serotonergic opioid; if used, monitor for serotonin syndrome.
What other medicines interact with Meperidine?
MediHelp also lists interactions of Meperidine with, for example, Alvimopan, Isocarboxazid, Methylene blue. The full list is on the Meperidine page.
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