Drug interactions
Haloperidol + Ketoconazole
Severity: Major
Haloperidol and Ketoconazole: 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
Both drugs can prolong the QT interval, and ketoconazole may also raise haloperidol exposure by inhibiting its CYP3A4-mediated metabolism. The combination increases the risk of torsades de pointes and serious ventricular arrhythmias, especially with electrolyte disturbances or cardiac disease.
What this interaction means in plain words
Haloperidol and Ketoconazole 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.
Haloperidol belongs to Central Nervous System; Ketoconazole belongs to Anti Fungals.
Why it happens
Additive QT prolongation plus CYP3A4 inhibition by ketoconazole reducing haloperidol clearance.
What to do
Avoid the combination where possible and choose a non-QT-prolonging antifungal or antipsychotic. If it is unavoidable, obtain a baseline and follow-up ECG, correct potassium and magnesium, and consider reducing the haloperidol dose.
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 Ketoconazole
- Alfuzosin + Ketoconazole Contraindicated
- Alprazolam + Ketoconazole Contraindicated
- Avanafil + Ketoconazole Contraindicated
- Conivaptan + Ketoconazole Contraindicated
- Dihydroergotamine intranasal + Ketoconazole Contraindicated
- Dihydroergotamine + Ketoconazole Contraindicated
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 Ketoconazole?
MediHelp rates the interaction as major. Haloperidol and Ketoconazole 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. Both drugs can prolong the QT interval, and ketoconazole may also raise haloperidol exposure by inhibiting its CYP3A4-mediated metabolism. The combination increases the risk of torsades de pointes and serious ventricular arrhythmias, especially with electrolyte disturbances or cardiac disease.
How serious is the interaction between Haloperidol and Ketoconazole?
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 where possible and choose a non-QT-prolonging antifungal or antipsychotic. If it is unavoidable, obtain a baseline and follow-up ECG, correct potassium and magnesium, and consider reducing the haloperidol dose.
What other medicines interact with Ketoconazole?
MediHelp also lists interactions of Ketoconazole with, for example, Alfuzosin, Alprazolam, Avanafil. The full list is on the Ketoconazole page.
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