Drug interactions
Chloroquine + Hydroxyzine
Severity: Major
Chloroquine 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
Both drugs can prolong the QT interval, so giving them together raises the risk of torsades de pointes and other serious ventricular arrhythmias. The risk is higher with electrolyte disturbances, bradycardia, or underlying heart disease.
What this interaction means in plain words
Chloroquine 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.
Chloroquine belongs to Anti Parasitic; Hydroxyzine belongs to Respiratory.
Why it happens
Additive blockade of cardiac hERG potassium channels causing delayed ventricular repolarization.
What to do
Prefer a non-QT-prolonging alternative to hydroxyzine such as a non-sedating agent where possible. If used together, obtain a baseline ECG, correct potassium and magnesium, and monitor QTc.
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 Chloroquine
- Chloroquine + Cisapride Contraindicated
- Chloroquine + Dofetilide Contraindicated
- Chloroquine + Dronedarone Contraindicated
- Chloroquine + Droperidol Contraindicated
- Chloroquine + Panobinostat Contraindicated
- Chloroquine + Pimozide 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 Chloroquine with Hydroxyzine?
MediHelp rates the interaction as major. Chloroquine 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. Both drugs can prolong the QT interval, so giving them together raises the risk of torsades de pointes and other serious ventricular arrhythmias. The risk is higher with electrolyte disturbances, bradycardia, or underlying heart disease.
How serious is the interaction between Chloroquine 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: Prefer a non-QT-prolonging alternative to hydroxyzine such as a non-sedating agent where possible. If used together, obtain a baseline ECG, correct potassium and magnesium, and monitor QTc.
What other medicines interact with Chloroquine?
MediHelp also lists interactions of Chloroquine with, for example, Cisapride, Dofetilide, Dronedarone. The full list is on the Chloroquine page.
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