Drug interactions
Fluoxetine + Formoterol
Severity: Moderate
Fluoxetine 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
Fluoxetine can prolong the QT interval, particularly at higher doses or with hypokalemia, and formoterol can add to QT effects and lower potassium. The combination may increase the risk of arrhythmia in susceptible patients.
What this interaction means in plain words
Fluoxetine 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.
Fluoxetine belongs to Central Nervous System; Formoterol belongs to Respiratory.
Why it happens
Additive QT prolongation with beta2-agonist-induced hypokalemia and sympathetic stimulation.
What to do
Monitor ECG in patients with cardiac disease or other QT risk factors, and maintain normal potassium and magnesium levels.
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 Fluoxetine
- Fluoxetine + Isocarboxazid Contraindicated
- Fluoxetine + Mavacamten Contraindicated
- Fluoxetine + Methylene blue Contraindicated
- Fluoxetine + Phenelzine Contraindicated
- Fluoxetine + Pimozide Contraindicated
- Fluoxetine + Rasagiline Contraindicated
Frequently asked questions
Can I take Fluoxetine with Formoterol?
MediHelp rates the interaction as moderate. Fluoxetine 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. Fluoxetine can prolong the QT interval, particularly at higher doses or with hypokalemia, and formoterol can add to QT effects and lower potassium. The combination may increase the risk of arrhythmia in susceptible patients.
How serious is the interaction between Fluoxetine 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 in patients with cardiac disease or other QT risk factors, and maintain normal potassium and magnesium levels.
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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