Drug interactions
Prochlorperazine + Promazine
Severity: Major
Prochlorperazine and Promazine: 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 phenothiazines that can prolong the QT interval, so combining them raises the risk of torsades de pointes. Sedative, anticholinergic and extrapyramidal effects are also additive.
What this interaction means in plain words
Prochlorperazine and Promazine 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 cardiac potassium channel blockade, plus additive dopamine blockade and sedation.
What to do
Avoid combining two phenothiazines and use a single agent at the lowest effective dose. If unavoidable, monitor the ECG and electrolytes.
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?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Prochlorperazine and Promazine, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 7 days on the web. No card needed.
References
- Almus Migraine Relief 3mg Buccal Tablets - SmPC sections 4.3/4.5 (class statement: neuroleptics; "There is an increased risk of arrhythmias when neuroleptics are used with concomitant QT prolonging drugs (including certain anti-arrhythmics, antidepressants, ") — electronic medicines compendium (UK SmPC)
Other interactions of Prochlorperazine
- Dronedarone + Prochlorperazine Contraindicated
- Ibutilide + Prochlorperazine Contraindicated
- Nilotinib + Prochlorperazine Contraindicated
- Pimozide + Prochlorperazine Contraindicated
- Prochlorperazine + Thioridazine Contraindicated
- Amiodarone + Prochlorperazine Major
Frequently asked questions
Can I take Prochlorperazine with Promazine?
MediHelp rates the interaction as major. Prochlorperazine and Promazine 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 phenothiazines that can prolong the QT interval, so combining them raises the risk of torsades de pointes. Sedative, anticholinergic and extrapyramidal effects are also additive.
How serious is the interaction between Prochlorperazine and Promazine?
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 combining two phenothiazines and use a single agent at the lowest effective dose. If unavoidable, monitor the ECG and electrolytes.
What other medicines interact with Prochlorperazine?
MediHelp also lists interactions of Prochlorperazine with, for example, Dronedarone, Ibutilide, Nilotinib. The full list is on the Prochlorperazine page.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
