Drug interactions
Promazine + Risperidone
Severity: Major
Promazine and Risperidone: 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
Both are antipsychotics that prolong the QT interval. Using them together increases the risk of ventricular arrhythmias, and also adds sedation, hypotension and extrapyramidal effects.
What this interaction means in plain words
Promazine and Risperidone 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 hERG potassium channel blockade, plus overlapping dopamine antagonism.
What to do
Avoid antipsychotic polypharmacy where possible. If unavoidable, check ECG and electrolytes and monitor for arrhythmia symptoms.
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 Risperidone
- Ibutilide + Risperidone Contraindicated
- Risperidone + Vandetanib Contraindicated
- Adagrasib + Risperidone Major
- Amiodarone + Risperidone Major
- Amisulpride + Risperidone Major
- Amoxapine + Risperidone Major
Frequently asked questions
Can I take Promazine with Risperidone?
MediHelp rates the interaction as major. Promazine and Risperidone 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. Both are antipsychotics that prolong the QT interval. Using them together increases the risk of ventricular arrhythmias, and also adds sedation, hypotension and extrapyramidal effects.
How serious is the interaction between Promazine and Risperidone?
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 antipsychotic polypharmacy where possible. If unavoidable, check ECG and electrolytes and monitor for arrhythmia symptoms.
What other medicines interact with Risperidone?
MediHelp also lists interactions of Risperidone with, for example, Ibutilide, Vandetanib, Adagrasib. The full list is on the Risperidone page.
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