Drug interactions
Pimavanserin + St john's wort
Severity: Major
Pimavanserin 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 induces CYP3A4 and can lower pimavanserin concentrations, reducing its benefit. Because it also has serotonergic activity, the interaction can extend beyond pharmacokinetics.
What this interaction means in plain words
Pimavanserin 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
Induction of CYP3A4 (and P-glycoprotein) by hyperforin increases pimavanserin clearance.
What to do
Avoid concomitant use; advise patients to stop the herbal product. If it cannot be avoided, monitor for loss of efficacy and consider increasing the pimavanserin dose.
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 Pimavanserin
- Lefamulin + Pimavanserin Contraindicated
- Pimavanserin + Pimozide Contraindicated
- Pimavanserin + Vandetanib Contraindicated
- Adagrasib + Pimavanserin Major
- Amiodarone + Pimavanserin Major
- Amisulpride + Pimavanserin Major
Frequently asked questions
Can I take Pimavanserin with St john's wort?
MediHelp rates the interaction as major. Pimavanserin 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 induces CYP3A4 and can lower pimavanserin concentrations, reducing its benefit. Because it also has serotonergic activity, the interaction can extend beyond pharmacokinetics.
How serious is the interaction between Pimavanserin 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 concomitant use; advise patients to stop the herbal product. If it cannot be avoided, monitor for loss of efficacy and consider increasing the pimavanserin dose.
What other medicines interact with Pimavanserin?
MediHelp also lists interactions of Pimavanserin with, for example, Lefamulin, Pimozide, Vandetanib. The full list is on the Pimavanserin page.
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