Drug interactions
Hydroxyzine + Quinidine
Severity: Major
Hydroxyzine and Quinidine: 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, so giving them together raises the risk of torsades de pointes and other ventricular arrhythmias. The risk is greater with electrolyte disturbances, bradycardia, structural heart disease or high doses.
What this interaction means in plain words
Hydroxyzine and Quinidine 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 belongs to Respiratory; Quinidine belongs to Anti Parasitic.
Why it happens
Additive blockade of cardiac repolarizing potassium currents causing pharmacodynamic QT prolongation.
What to do
Use a non-QT-prolonging alternative to hydroxyzine where possible. If combined, obtain a baseline and follow-up ECG and correct potassium and magnesium.
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 Quinidine
- Adagrasib + Quinidine Contraindicated
- Arsenic trioxide + Quinidine Contraindicated
- Artemether / lumefantrine + Quinidine Contraindicated
- Chloroquine + Quinidine Contraindicated
- Dofetilide + Quinidine Contraindicated
- Dronedarone + Quinidine 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 Hydroxyzine with Quinidine?
MediHelp rates the interaction as major. Hydroxyzine and Quinidine 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 ventricular arrhythmias. The risk is greater with electrolyte disturbances, bradycardia, structural heart disease or high doses.
How serious is the interaction between Hydroxyzine and Quinidine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Use a non-QT-prolonging alternative to hydroxyzine where possible. If combined, obtain a baseline and follow-up ECG and correct potassium and magnesium.
What other medicines interact with Quinidine?
MediHelp also lists interactions of Quinidine with, for example, Adagrasib, Arsenic trioxide, Artemether / lumefantrine. The full list is on the Quinidine page.
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