Drug interactions
Encainide + Thioridazine
Severity: Major
Encainide and Thioridazine: 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
Encainide is metabolized by CYP2D6 and thioridazine inhibits this enzyme, so encainide exposure may rise. Encainide is an antiarrhythmic with proarrhythmic potential and is rarely used now, and thioridazine adds QT risk.
What this interaction means in plain words
Encainide and Thioridazine 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
CYP2D6 inhibition by thioridazine reduces encainide metabolism, plus additive effects on cardiac conduction.
What to do
Avoid the combination; if encainide is used, monitor ECG closely and consider an alternative antipsychotic.
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 Thioridazine
- Abiraterone + Thioridazine Contraindicated
- Adagrasib + Thioridazine Contraindicated
- Amiodarone + Thioridazine Contraindicated
- Amisulpride + Thioridazine Contraindicated
- Amitriptyline + Thioridazine Contraindicated
- Amoxapine + Thioridazine Contraindicated
Frequently asked questions
Can I take Encainide with Thioridazine?
MediHelp rates the interaction as major. Encainide and Thioridazine 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. Encainide is metabolized by CYP2D6 and thioridazine inhibits this enzyme, so encainide exposure may rise. Encainide is an antiarrhythmic with proarrhythmic potential and is rarely used now, and thioridazine adds QT risk.
How serious is the interaction between Encainide and Thioridazine?
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; if encainide is used, monitor ECG closely and consider an alternative antipsychotic.
What other medicines interact with Thioridazine?
MediHelp also lists interactions of Thioridazine with, for example, Abiraterone, Adagrasib, Amiodarone. The full list is on the Thioridazine page.
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