Drug interactions
Marijuana + Pimozide
Severity: Major
Marijuana and Pimozide: 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
Cannabinoids may inhibit CYP enzymes involved in pimozide metabolism, possibly raising pimozide levels. The clinical significance is uncertain, but pimozide has a narrow margin regarding QT prolongation.
What this interaction means in plain words
Marijuana and Pimozide 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
Cannabinoids may inhibit CYP3A4 and other enzymes, though the effect on pimozide is largely theoretical.
What to do
Advise patients to avoid cannabis use. Obtain an ECG if use continues and monitor for dizziness, palpitations or syncope.
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 Pimozide
- Adagrasib + Pimozide Contraindicated
- Amiodarone + Pimozide Contraindicated
- Amisulpride + Pimozide Contraindicated
- Amitriptyline + Pimozide Contraindicated
- Amoxapine + Pimozide Contraindicated
- Anagrelide + Pimozide Contraindicated
Frequently asked questions
Can I take Marijuana with Pimozide?
MediHelp rates the interaction as major. Marijuana and Pimozide 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. Cannabinoids may inhibit CYP enzymes involved in pimozide metabolism, possibly raising pimozide levels. The clinical significance is uncertain, but pimozide has a narrow margin regarding QT prolongation.
How serious is the interaction between Marijuana and Pimozide?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Advise patients to avoid cannabis use. Obtain an ECG if use continues and monitor for dizziness, palpitations or syncope.
What other medicines interact with Pimozide?
MediHelp also lists interactions of Pimozide with, for example, Adagrasib, Amiodarone, Amisulpride. The full list is on the Pimozide page.
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