Drug interactions
Prochlorperazine + Trifluoperazine
Severity: Major
Prochlorperazine and Trifluoperazine: 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. Extrapyramidal and sedative effects are also additive.
What this interaction means in plain words
Prochlorperazine and Trifluoperazine 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 D2 blockade.
What to do
Avoid using two phenothiazines together and use a single agent at the lowest effective dose. If unavoidable, monitor the ECG, electrolytes and extrapyramidal signs.
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
- 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 Trifluoperazine?
MediHelp rates the interaction as major. Prochlorperazine and Trifluoperazine 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. Extrapyramidal and sedative effects are also additive.
How serious is the interaction between Prochlorperazine and Trifluoperazine?
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 using two phenothiazines together and use a single agent at the lowest effective dose. If unavoidable, monitor the ECG, electrolytes and extrapyramidal signs.
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.
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