Drug interactions
Flecainide + Hydroxyzine
Severity: Major
Flecainide 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 is associated with QT prolongation and torsades de pointes, and flecainide has proarrhythmic effects. The combination may increase the risk of ventricular arrhythmia, particularly in older patients or those with cardiac disease.
What this interaction means in plain words
Flecainide 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.
Flecainide belongs to Cardiovascular; Hydroxyzine belongs to Respiratory.
Why it happens
Additive effects on cardiac repolarization.
What to do
Avoid if possible and choose a non-QT-prolonging anxiolytic or antihistamine. If needed, use the lowest dose with ECG and electrolyte monitoring.
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 Flecainide
- Flecainide + Nirmatrelvir Contraindicated
- Flecainide + Nirmatrelvir / ritonavir Contraindicated
- Flecainide + Pimozide Contraindicated
- Flecainide + Ritonavir Contraindicated
- Flecainide + Thioridazine Contraindicated
- Flecainide + Tipranavir 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 Flecainide with Hydroxyzine?
MediHelp rates the interaction as major. Flecainide 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 is associated with QT prolongation and torsades de pointes, and flecainide has proarrhythmic effects. The combination may increase the risk of ventricular arrhythmia, particularly in older patients or those with cardiac disease.
How serious is the interaction between Flecainide 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 if possible and choose a non-QT-prolonging anxiolytic or antihistamine. If needed, use the lowest dose with ECG and electrolyte monitoring.
What other medicines interact with Flecainide?
MediHelp also lists interactions of Flecainide with, for example, Nirmatrelvir, Nirmatrelvir / ritonavir, Pimozide. The full list is on the Flecainide page.
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