Drug interactions
Risperidone + St john's wort
Severity: Moderate
Risperidone 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 can lower circulating concentrations of risperidone and its active metabolite. This may reduce antipsychotic efficacy and risk symptom relapse.
What this interaction means in plain words
Risperidone 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
Induction of P-glycoprotein and CYP3A4 by St John's wort increases risperidone clearance and reduces exposure.
What to do
Avoid the combination where possible; if started or stopped, monitor psychiatric symptoms and adjust the risperidone dose accordingly.
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 Risperidone
- Ibutilide + Risperidone Contraindicated
- Risperidone + Vandetanib Contraindicated
- Adagrasib + Risperidone Major
- Amiodarone + Risperidone Major
- Amisulpride + Risperidone Major
- Amoxapine + Risperidone Major
Frequently asked questions
Can I take Risperidone with St john's wort?
MediHelp rates the interaction as moderate. Risperidone 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 can lower circulating concentrations of risperidone and its active metabolite. This may reduce antipsychotic efficacy and risk symptom relapse.
How serious is the interaction between Risperidone 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: Avoid the combination where possible; if started or stopped, monitor psychiatric symptoms and adjust the risperidone dose accordingly.
What other medicines interact with Risperidone?
MediHelp also lists interactions of Risperidone with, for example, Ibutilide, Vandetanib, Adagrasib. The full list is on the Risperidone page.
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