Drug interactions
Pimavanserin + Rifampin
Severity: Major
Pimavanserin and Rifampin: 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
Rifampin is a strong CYP3A4 inducer and markedly lowers pimavanserin exposure. This can lead to loss of efficacy in Parkinson's disease psychosis.
What this interaction means in plain words
Pimavanserin and Rifampin 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
Rifampin potently induces CYP3A4, increasing pimavanserin clearance.
What to do
Avoid the combination if possible; otherwise monitor for relapse of psychotic symptoms and consider increasing the pimavanserin dose. Reduce the dose back after rifampin is stopped.
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 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 Rifampin?
MediHelp rates the interaction as major. Pimavanserin and Rifampin 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. Rifampin is a strong CYP3A4 inducer and markedly lowers pimavanserin exposure. This can lead to loss of efficacy in Parkinson's disease psychosis.
How serious is the interaction between Pimavanserin and Rifampin?
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 if possible; otherwise monitor for relapse of psychotic symptoms and consider increasing the pimavanserin dose. Reduce the dose back after rifampin is stopped.
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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