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Drug interactions

Amisulpride + Promethazine

Severity: Major

Amisulpride and Promethazine: 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

Promethazine and amisulpride both can prolong the QTc interval, increasing the risk of torsades de pointes. Risk is higher with electrolyte disturbance, bradycardia or structural heart disease.

What this interaction means in plain words

Amisulpride and Promethazine 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.

Amisulpride belongs to Central Nervous System; Promethazine belongs to Respiratory.

Evidence level: Moderate

Why it happens

Additive QT prolongation through cardiac potassium channel blockade.

What to do

Avoid if possible; if combined, obtain a baseline and follow-up ECG and correct potassium and magnesium.

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?

Bring a full list of your medicines, including over-the-counter products, supplements and herbal remedies, to every pharmacy visit.

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Frequently asked questions

Can I take Amisulpride with Promethazine?

MediHelp rates the interaction as major. Amisulpride and Promethazine 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. Promethazine and amisulpride both can prolong the QTc interval, increasing the risk of torsades de pointes. Risk is higher with electrolyte disturbance, bradycardia or structural heart disease.

How serious is the interaction between Amisulpride and Promethazine?

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 if possible; if combined, obtain a baseline and follow-up ECG and correct potassium and magnesium.

What other medicines interact with Promethazine?

MediHelp also lists interactions of Promethazine with, for example, Ibutilide, Pimozide, Thioridazine. The full list is on the Promethazine page.

Full monographs, dosing and an interaction checker in the MediHelp app

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