Drug interactions
Flecainide + Haloperidol
Severity: Major
Flecainide and Haloperidol: major interaction.
Last updated Sources: UK SmPC
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
Haloperidol inhibits CYP2D6 and can increase flecainide concentrations, and both drugs can prolong the QT interval or slow conduction. The combination raises the risk of torsades de pointes and other ventricular arrhythmias.
What this interaction means in plain words
Flecainide and Haloperidol 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; Haloperidol belongs to Central Nervous System.
Why it happens
CYP2D6 inhibition by haloperidol reduces flecainide clearance, combined with additive pharmacodynamic effects on cardiac repolarization and conduction.
What to do
Avoid the combination where possible, or use an alternative antipsychotic with less QT effect. If used together, monitor ECG continuously or frequently and consider a lower flecainide dose guided by plasma levels.
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 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 Flecainide with Haloperidol?
MediHelp rates the interaction as major. Flecainide and Haloperidol 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 inhibits CYP2D6 and can increase flecainide concentrations, and both drugs can prolong the QT interval or slow conduction. The combination raises the risk of torsades de pointes and other ventricular arrhythmias.
How serious is the interaction between Flecainide and Haloperidol?
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, or use an alternative antipsychotic with less QT effect. If used together, monitor ECG continuously or frequently and consider a lower flecainide dose guided by plasma levels.
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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