Drug interactions
Haloperidol + Primidone
Severity: Moderate
Haloperidol and Primidone: 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
Primidone, partly metabolised to phenobarbital, adds to haloperidol sedation and induces hepatic enzymes. This can reduce haloperidol concentrations and may weaken antipsychotic control.
What this interaction means in plain words
Haloperidol and Primidone 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.
Haloperidol belongs to Central Nervous System; Primidone belongs to Central Nervous System.
Why it happens
Additive CNS depression and enzyme induction (CYP3A4) by primidone and its phenobarbital metabolite.
What to do
Monitor sedation and psychiatric response, and raise the haloperidol dose if efficacy falls. Recheck dosing if primidone 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 Haloperidol
- Dofetilide + Haloperidol Contraindicated
- Dronedarone + Haloperidol Contraindicated
- Haloperidol + Ibutilide Contraindicated
- Haloperidol + Levoketoconazole Contraindicated
- Haloperidol + Panobinostat Contraindicated
- Haloperidol + Pimozide Contraindicated
Other interactions of Primidone
- Lorlatinib + Primidone Contraindicated
- Lurasidone + Primidone Contraindicated
- Primidone + Ranolazine Contraindicated
- Primidone + Sofosbuvir-velpatasvir-voxilaprevir Contraindicated
- Primidone + Voriconazole Contraindicated
- Abiraterone + Primidone Major
Frequently asked questions
Can I take Haloperidol with Primidone?
MediHelp rates the interaction as moderate. Haloperidol and Primidone 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. Primidone, partly metabolised to phenobarbital, adds to haloperidol sedation and induces hepatic enzymes. This can reduce haloperidol concentrations and may weaken antipsychotic control.
How serious is the interaction between Haloperidol and Primidone?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor sedation and psychiatric response, and raise the haloperidol dose if efficacy falls. Recheck dosing if primidone is stopped.
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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