Drug interactions
Haloperidol + Marijuana
Severity: Moderate
Haloperidol and Marijuana: 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
Cannabis can add to haloperidol sedation and dizziness, and cannabidiol may inhibit CYP2D6 and CYP3A4 and raise haloperidol levels. Cannabis can also worsen psychosis and cause tachycardia.
What this interaction means in plain words
Haloperidol and Marijuana 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
Additive CNS depression plus possible cannabinoid inhibition of CYP2D6 and CYP3A4.
What to do
Advise patients to avoid cannabis, particularly with psychotic illness. Monitor sedation, extrapyramidal symptoms and psychiatric status if use continues.
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 Haloperidol
- Dofetilide + Haloperidol Contraindicated
- Dronedarone + Haloperidol Contraindicated
- Haloperidol + Ibutilide Contraindicated
- Haloperidol + Levoketoconazole Contraindicated
- Haloperidol + Panobinostat Contraindicated
- Haloperidol + Pimozide Contraindicated
Frequently asked questions
Can I take Haloperidol with Marijuana?
MediHelp rates the interaction as moderate. Haloperidol and Marijuana 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. Cannabis can add to haloperidol sedation and dizziness, and cannabidiol may inhibit CYP2D6 and CYP3A4 and raise haloperidol levels. Cannabis can also worsen psychosis and cause tachycardia.
How serious is the interaction between Haloperidol and Marijuana?
MediHelp rates it moderate, 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, particularly with psychotic illness. Monitor sedation, extrapyramidal symptoms and psychiatric status if use continues.
What other medicines interact with Haloperidol?
MediHelp also lists interactions of Haloperidol with, for example, Dofetilide, Dronedarone, Ibutilide. The full list is on the Haloperidol page.
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