Drug interactions
Chlorpromazine + Protriptyline
Severity: Major
Chlorpromazine and Protriptyline: major interaction.
Last updated Sources: US FDA label
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 agents can prolong the QT interval, and combining them increases the risk of serious ventricular arrhythmias. Chlorpromazine may also raise tricyclic concentrations and add anticholinergic, sedative and hypotensive effects.
What this interaction means in plain words
Chlorpromazine and Protriptyline 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, with chlorpromazine inhibiting CYP2D6-mediated metabolism of protriptyline and additive anticholinergic effects.
What to do
Avoid if possible; if used together, check a baseline and follow-up ECG, correct electrolytes, and monitor for anticholinergic toxicity. Reduce the protriptyline dose if signs of excess exposure appear.
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 Chlorpromazine
- Chlorpromazine + Dofetilide Contraindicated
- Chlorpromazine + Dronedarone Contraindicated
- Chlorpromazine + Droperidol Contraindicated
- Chlorpromazine + Ibutilide Contraindicated
- Chlorpromazine + Metrizamide Contraindicated
- Chlorpromazine + Panobinostat Contraindicated
Frequently asked questions
Can I take Chlorpromazine with Protriptyline?
MediHelp rates the interaction as major. Chlorpromazine and Protriptyline 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 agents can prolong the QT interval, and combining them increases the risk of serious ventricular arrhythmias. Chlorpromazine may also raise tricyclic concentrations and add anticholinergic, sedative and hypotensive effects.
How serious is the interaction between Chlorpromazine and Protriptyline?
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 used together, check a baseline and follow-up ECG, correct electrolytes, and monitor for anticholinergic toxicity. Reduce the protriptyline dose if signs of excess exposure appear.
What other medicines interact with Chlorpromazine?
MediHelp also lists interactions of Chlorpromazine with, for example, Dofetilide, Dronedarone, Droperidol. The full list is on the Chlorpromazine page.
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