Drug interactions
Chlorpromazine + Hydroxyzine
Severity: Major
Chlorpromazine and Hydroxyzine: major interaction.
Last updated Sources: Health Canada product monograph
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
Hydroxyzine can prolong the QT interval and is sedating and anticholinergic. Combined with chlorpromazine, the risk of torsades de pointes rises, and sedation and anticholinergic effects are additive.
What this interaction means in plain words
Chlorpromazine and Hydroxyzine 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.
Chlorpromazine belongs to Central Nervous System; Hydroxyzine belongs to Respiratory.
Why it happens
Additive QT prolongation plus additive CNS depression and anticholinergic effects.
What to do
Avoid the combination when possible, particularly in patients with cardiac disease, electrolyte disturbance or advanced age. If used, monitor ECG and electrolytes and watch for oversedation.
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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References
Other interactions of Chlorpromazine
- Chlorpromazine + Dofetilide Contraindicated
- Chlorpromazine + Dronedarone Contraindicated
- Chlorpromazine + Droperidol Contraindicated
- Chlorpromazine + Ibutilide Contraindicated
- Chlorpromazine + Metrizamide Contraindicated
- Chlorpromazine + Panobinostat Contraindicated
Other interactions of Hydroxyzine
- Droperidol + Hydroxyzine Contraindicated
- Hydroxyzine + Pimozide Contraindicated
- Hydroxyzine + Thioridazine Contraindicated
- Hydroxyzine + Vandetanib Contraindicated
- Alfentanil + Hydroxyzine Major
- Amiodarone + Hydroxyzine Major
Frequently asked questions
Can I take Chlorpromazine with Hydroxyzine?
MediHelp rates the interaction as major. Chlorpromazine and Hydroxyzine 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. Hydroxyzine can prolong the QT interval and is sedating and anticholinergic. Combined with chlorpromazine, the risk of torsades de pointes rises, and sedation and anticholinergic effects are additive.
How serious is the interaction between Chlorpromazine and Hydroxyzine?
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 when possible, particularly in patients with cardiac disease, electrolyte disturbance or advanced age. If used, monitor ECG and electrolytes and watch for oversedation.
What other medicines interact with Chlorpromazine?
MediHelp also lists interactions of Chlorpromazine with, for example, Dofetilide, Dronedarone, Droperidol. The full list is on the Chlorpromazine page.
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