Drug interactions
Chlorpromazine + Tetrabenazine
Severity: Major
Chlorpromazine and Tetrabenazine: 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 drugs prolong the QT interval, so combined use increases the risk of torsades de pointes. Both also cause sedation and parkinsonism, and chlorpromazine inhibits tetrabenazine metabolism.
What this interaction means in plain words
Chlorpromazine and Tetrabenazine 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.
Chlorpromazine belongs to Central Nervous System; Tetrabenazine belongs to Central Nervous System.
Why it happens
Additive QT prolongation; chlorpromazine inhibits CYP2D6, raising exposure to the active tetrabenazine metabolites, with additive dopamine antagonism.
What to do
Avoid the combination where possible; otherwise obtain ECG monitoring, correct electrolytes and limit the tetrabenazine dose. Watch for extrapyramidal symptoms, sedation and depression.
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 Chlorpromazine and Tetrabenazine, 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
Other interactions of Chlorpromazine
- Chlorpromazine + Dofetilide Contraindicated
- Chlorpromazine + Dronedarone Contraindicated
- Chlorpromazine + Droperidol Contraindicated
- Chlorpromazine + Ibutilide Contraindicated
- Chlorpromazine + Metrizamide Contraindicated
- Chlorpromazine + Panobinostat Contraindicated
Other interactions of Tetrabenazine
- Dronedarone + Tetrabenazine Contraindicated
- Isocarboxazid + Tetrabenazine Contraindicated
- Linezolid + Tetrabenazine Contraindicated
- Phenelzine + Tetrabenazine Contraindicated
- Pimozide + Tetrabenazine Contraindicated
- Procarbazine + Tetrabenazine Contraindicated
Frequently asked questions
Can I take Chlorpromazine with Tetrabenazine?
MediHelp rates the interaction as major. Chlorpromazine and Tetrabenazine 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 drugs prolong the QT interval, so combined use increases the risk of torsades de pointes. Both also cause sedation and parkinsonism, and chlorpromazine inhibits tetrabenazine metabolism.
How serious is the interaction between Chlorpromazine and Tetrabenazine?
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 the combination where possible; otherwise obtain ECG monitoring, correct electrolytes and limit the tetrabenazine dose. Watch for extrapyramidal symptoms, sedation and depression.
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.
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.
