Drug interactions
Carbamazepine + Pimavanserin
Severity: Major
Carbamazepine and Pimavanserin: 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
Strong CYP3A4 inducers such as carbamazepine substantially reduce pimavanserin exposure and may reduce antipsychotic efficacy in Parkinson's disease psychosis. Labeling advises considering a higher pimavanserin dose.
What this interaction means in plain words
Carbamazepine and Pimavanserin 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.
Carbamazepine belongs to Central Nervous System; Pimavanserin belongs to Central Nervous System.
Why it happens
Carbamazepine induces CYP3A4, which is the main route of pimavanserin metabolism.
What to do
Avoid the combination if possible. If it is unavoidable, monitor for loss of efficacy and consider increasing the pimavanserin dose, then reduce it if carbamazepine 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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Other interactions of Carbamazepine
- Artemether / lumefantrine + Carbamazepine Contraindicated
- Cabotegravir + Carbamazepine Contraindicated
- Carbamazepine + Delamanid Contraindicated
- Carbamazepine + Dienogest / estradiol valerate Contraindicated
- Carbamazepine + Doravirine Contraindicated
- Carbamazepine + Elbasvir / grazoprevir Contraindicated
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 Carbamazepine with Pimavanserin?
MediHelp rates the interaction as major. Carbamazepine and Pimavanserin 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. Strong CYP3A4 inducers such as carbamazepine substantially reduce pimavanserin exposure and may reduce antipsychotic efficacy in Parkinson's disease psychosis. Labeling advises considering a higher pimavanserin dose.
How serious is the interaction between Carbamazepine and Pimavanserin?
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. If it is unavoidable, monitor for loss of efficacy and consider increasing the pimavanserin dose, then reduce it if carbamazepine is stopped.
What other medicines interact with Carbamazepine?
MediHelp also lists interactions of Carbamazepine with, for example, Artemether / lumefantrine, Cabotegravir, Delamanid. The full list is on the Carbamazepine page.
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