Drug interactions
Dofetilide + Fluoxetine
Severity: Major
Dofetilide and Fluoxetine: 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
Dofetilide has a substantial risk of torsades de pointes, and fluoxetine can add further QT prolongation. Fluoxetine may also affect dofetilide handling, so the combination can lead to life-threatening arrhythmia.
What this interaction means in plain words
Dofetilide and Fluoxetine 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.
Dofetilide belongs to Cardiovascular; Fluoxetine belongs to Central Nervous System.
Why it happens
Additive QT prolongation through blocked cardiac repolarizing potassium current.
What to do
Avoid the combination where possible and choose an alternative antidepressant with less QT effect, such as sertraline. If used, monitor ECG and keep potassium and magnesium normal.
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 Fluoxetine
- Fluoxetine + Isocarboxazid Contraindicated
- Fluoxetine + Mavacamten Contraindicated
- Fluoxetine + Methylene blue Contraindicated
- Fluoxetine + Phenelzine Contraindicated
- Fluoxetine + Pimozide Contraindicated
- Fluoxetine + Rasagiline Contraindicated
Other interactions of Dofetilide
- Amiodarone + Dofetilide Contraindicated
- Amisulpride + Dofetilide Contraindicated
- Amlodipine-hydrochlorothiazide-valsartan + Dofetilide Contraindicated
- Amlodipine-olmesartan-hydrochlorothiazide + Dofetilide Contraindicated
- Candesartan-hydrochlorothiazide + Dofetilide Contraindicated
- Captopril-hydrochlorothiazide + Dofetilide Contraindicated
Frequently asked questions
Can I take Dofetilide with Fluoxetine?
MediHelp rates the interaction as major. Dofetilide and Fluoxetine 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. Dofetilide has a substantial risk of torsades de pointes, and fluoxetine can add further QT prolongation. Fluoxetine may also affect dofetilide handling, so the combination can lead to life-threatening arrhythmia.
How serious is the interaction between Dofetilide and Fluoxetine?
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 and choose an alternative antidepressant with less QT effect, such as sertraline. If used, monitor ECG and keep potassium and magnesium normal.
What other medicines interact with Fluoxetine?
MediHelp also lists interactions of Fluoxetine with, for example, Isocarboxazid, Mavacamten, Methylene blue. The full list is on the Fluoxetine page.
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