Drug interactions
Disopyramide + Formoterol
Severity: Major
Disopyramide 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
Disopyramide is a class Ia antiarrhythmic that prolongs QT, and formoterol can add to QT prolongation and cause hypokalemia. Together they raise the risk of torsades de pointes.
What this interaction means in plain words
Disopyramide 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.
Disopyramide belongs to Cardiovascular; Formoterol belongs to Respiratory.
Why it happens
Additive QT prolongation, with beta-agonist-induced hypokalemia increasing proarrhythmic risk.
What to do
Avoid the combination if possible; otherwise monitor ECG and serum potassium and magnesium closely.
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 Disopyramide
- Amisulpride + Disopyramide Contraindicated
- Desipramine + Disopyramide Contraindicated
- Disopyramide + Dronedarone Contraindicated
- Disopyramide + Itraconazole Contraindicated
- Disopyramide + Ketoconazole Contraindicated
- Disopyramide + Maprotiline Contraindicated
Frequently asked questions
Can I take Disopyramide with Formoterol?
MediHelp rates the interaction as major. Disopyramide 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. Disopyramide is a class Ia antiarrhythmic that prolongs QT, and formoterol can add to QT prolongation and cause hypokalemia. Together they raise the risk of torsades de pointes.
How serious is the interaction between Disopyramide 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: Avoid the combination if possible; otherwise monitor ECG and serum potassium and magnesium closely.
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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