Drug interactions
Flecainide + Formoterol
Severity: Moderate
Flecainide and Formoterol: moderate interaction.
Last updated
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
Flecainide is a class IC antiarrhythmic with proarrhythmic potential and conduction slowing, and formoterol can cause tachycardia and hypokalemia. Hypokalemia increases flecainide's proarrhythmic risk, so the combination may raise the risk of serious ventricular arrhythmias, especially in structural heart disease.
What this interaction means in plain words
Flecainide and Formoterol can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Flecainide belongs to Cardiovascular; Formoterol belongs to Respiratory.
Why it happens
Additive proarrhythmic effects: flecainide conduction slowing and QRS/QT effects combined with beta2-agonist-induced tachycardia and hypokalemia.
What to do
Monitor ECG and keep serum potassium and magnesium in the normal range; report palpitations or syncope promptly.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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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 Flecainide
- Flecainide + Nirmatrelvir Contraindicated
- Flecainide + Nirmatrelvir / ritonavir Contraindicated
- Flecainide + Pimozide Contraindicated
- Flecainide + Ritonavir Contraindicated
- Flecainide + Thioridazine Contraindicated
- Flecainide + Tipranavir Contraindicated
Frequently asked questions
Can I take Flecainide with Formoterol?
MediHelp rates the interaction as moderate. Flecainide and Formoterol can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Flecainide is a class IC antiarrhythmic with proarrhythmic potential and conduction slowing, and formoterol can cause tachycardia and hypokalemia. Hypokalemia increases flecainide's proarrhythmic risk, so the combination may raise the risk of serious ventricular arrhythmias, especially in structural heart disease.
How serious is the interaction between Flecainide and Formoterol?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor ECG and keep serum potassium and magnesium in the normal range; report palpitations or syncope promptly.
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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