Drug interactions
Chlorpromazine + Formoterol
Severity: Major
Chlorpromazine and Formoterol: 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
Chlorpromazine can prolong the QT interval, and formoterol may add to this through tachycardia and hypokalemia. Together they increase the risk of torsades de pointes, especially in patients with other risk factors.
What this interaction means in plain words
Chlorpromazine and Formoterol 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; Formoterol belongs to Respiratory.
Why it happens
Additive QT prolongation, with beta-2 agonist-induced hypokalemia increasing proarrhythmic risk.
What to do
Check and correct potassium and magnesium, and monitor the ECG for QTc prolongation. Consider an alternative if QTc is already prolonged.
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 Formoterol
- Adagrasib + Formoterol Major
- Amiodarone + Formoterol Major
- Amisulpride + Formoterol Major
- Amitriptyline + Formoterol Major
- Amoxapine + Formoterol Major
- Arformoterol + Formoterol Major
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 Formoterol?
MediHelp rates the interaction as major. Chlorpromazine and Formoterol 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 can prolong the QT interval, and formoterol may add to this through tachycardia and hypokalemia. Together they increase the risk of torsades de pointes, especially in patients with other risk factors.
How serious is the interaction between Chlorpromazine and Formoterol?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Check and correct potassium and magnesium, and monitor the ECG for QTc prolongation. Consider an alternative if QTc is already prolonged.
What other medicines interact with Formoterol?
MediHelp also lists interactions of Formoterol with, for example, Adagrasib, Amiodarone, Amisulpride. The full list is on the Formoterol page.
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