Drug interactions
Chlorpromazine + Procainamide
Severity: Major
Chlorpromazine and Procainamide: 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
Procainamide is a class IA antiarrhythmic that prolongs repolarization, and chlorpromazine has additional QT-prolonging effects. The combination increases the risk of torsades de pointes.
What this interaction means in plain words
Chlorpromazine and Procainamide 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.
Why it happens
Additive QT prolongation through potassium channel blockade and sodium channel effects.
What to do
Avoid the combination where possible and choose an antipsychotic with lower QT liability. If it cannot be avoided, monitor the ECG and keep electrolytes normal.
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
Frequently asked questions
Can I take Chlorpromazine with Procainamide?
MediHelp rates the interaction as major. Chlorpromazine and Procainamide 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. Procainamide is a class IA antiarrhythmic that prolongs repolarization, and chlorpromazine has additional QT-prolonging effects. The combination increases the risk of torsades de pointes.
How serious is the interaction between Chlorpromazine and Procainamide?
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 and choose an antipsychotic with lower QT liability. If it cannot be avoided, monitor the ECG and keep electrolytes normal.
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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