Drug interactions
Clozapine + Ibutilide
Severity: Major
Clozapine and Ibutilide: major interaction.
Last updated Sources: US FDA label
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
Ibutilide is a class III antiarrhythmic with a substantial risk of torsades de pointes. Adding clozapine increases QT liability, which can contribute to life-threatening arrhythmia.
What this interaction means in plain words
Clozapine and Ibutilide 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.
Clozapine belongs to Central Nervous System; Ibutilide belongs to Cardiovascular.
Why it happens
Additive prolongation of cardiac repolarisation; ibutilide enhances the inward sodium current and blocks IKr.
What to do
Avoid the combination where possible. If ibutilide is needed for cardioversion, correct electrolytes first and keep continuous ECG monitoring for several hours afterward.
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 Clozapine
- Clozapine + Deferiprone Contraindicated
- Clozapine + Irinotecan Contraindicated
- Clozapine + Pimozide Contraindicated
- Clozapine + Thioridazine Contraindicated
- Acalabrutinib + Clozapine Major
- Adagrasib + Clozapine Major
Other interactions of Ibutilide
- Amiodarone + Ibutilide Contraindicated
- Amisulpride + Ibutilide Contraindicated
- Chlorpromazine + Ibutilide Contraindicated
- Clarithromycin + Ibutilide Contraindicated
- Desipramine + Ibutilide Contraindicated
- Dolasetron + Ibutilide Contraindicated
Frequently asked questions
Can I take Clozapine with Ibutilide?
MediHelp rates the interaction as major. Clozapine and Ibutilide 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. Ibutilide is a class III antiarrhythmic with a substantial risk of torsades de pointes. Adding clozapine increases QT liability, which can contribute to life-threatening arrhythmia.
How serious is the interaction between Clozapine and Ibutilide?
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. If ibutilide is needed for cardioversion, correct electrolytes first and keep continuous ECG monitoring for several hours afterward.
What other medicines interact with Clozapine?
MediHelp also lists interactions of Clozapine with, for example, Deferiprone, Irinotecan, Pimozide. The full list is on the Clozapine page.
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