Drug interactions
Ibutilide + Promethazine
Severity: Contraindicated
Ibutilide and Promethazine: contraindicated 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
Ibutilide markedly prolongs repolarization and can cause torsades de pointes, and adding another QT-prolonging drug such as promethazine increases that risk further.
What this interaction means in plain words
Ibutilide and Promethazine are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two.
Ibutilide belongs to Cardiovascular; Promethazine belongs to Respiratory.
Why it happens
Additive QT prolongation through cardiac potassium channel blockade.
What to do
Avoid giving promethazine around ibutilide administration; use a non-QT-prolonging alternative. Ibutilide requires continuous ECG monitoring.
What to ask your pharmacist
- Is there an alternative to one of these two medicines for me?
- If both are essential, who is monitoring me and how often?
- Which symptoms mean I should stop and seek help straight away?
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Other interactions of Promethazine
- Pimozide + Promethazine Contraindicated
- Promethazine + Thioridazine Contraindicated
- Alfentanil + Promethazine Major
- Amiodarone + Promethazine Major
- Amisulpride + Promethazine Major
- Belladonna and opium + Promethazine 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 Ibutilide with Promethazine?
MediHelp rates the interaction as contraindicated. Ibutilide and Promethazine are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two. Ibutilide markedly prolongs repolarization and can cause torsades de pointes, and adding another QT-prolonging drug such as promethazine increases that risk further.
How serious is the interaction between Ibutilide and Promethazine?
MediHelp rates it contraindicated, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid giving promethazine around ibutilide administration; use a non-QT-prolonging alternative. Ibutilide requires continuous ECG monitoring.
What other medicines interact with Promethazine?
MediHelp also lists interactions of Promethazine with, for example, Pimozide, Thioridazine, Alfentanil. The full list is on the Promethazine page.
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