Drug interactions
Phenobarbital + Pimavanserin
Severity: Moderate
Phenobarbital and Pimavanserin: 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
Phenobarbital is a CYP3A4 inducer and can reduce pimavanserin concentrations, which may lead to loss of efficacy. Additive sedation is also possible.
What this interaction means in plain words
Phenobarbital and Pimavanserin 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
Phenobarbital induces CYP3A4, increasing pimavanserin metabolism.
What to do
Avoid if possible; if combined, monitor psychosis control and consider raising the pimavanserin dose. Reassess the dose if phenobarbital is stopped.
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 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 Phenobarbital with Pimavanserin?
MediHelp rates the interaction as moderate. Phenobarbital and Pimavanserin 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. Phenobarbital is a CYP3A4 inducer and can reduce pimavanserin concentrations, which may lead to loss of efficacy. Additive sedation is also possible.
How serious is the interaction between Phenobarbital and Pimavanserin?
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 if possible; if combined, monitor psychosis control and consider raising the pimavanserin dose. Reassess the dose if phenobarbital 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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