Drug interactions
Fluoxetine + Lumefantrine
Severity: Major
Fluoxetine and Lumefantrine: major interaction.
Last updated Sources: UK SmPC
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
Lumefantrine is partly metabolised by CYP2D6 and can prolong the QT interval. Fluoxetine inhibits CYP2D6 and may itself lengthen QT, so combined use may increase the risk of arrhythmia.
What this interaction means in plain words
Fluoxetine and Lumefantrine 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.
Why it happens
Fluoxetine inhibits CYP2D6 and both drugs have additive QT-prolonging effects.
What to do
Avoid the combination when alternatives exist. Otherwise obtain a baseline ECG, correct potassium and magnesium, and monitor QTc.
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?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Fluoxetine and Lumefantrine, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 7 days on the web. No card needed.
References
- Fluoxetine 10 mg hard capsules - SmPC sections 4.3/4.5 (class statement: medicinal products that prolong the QT interval; "co-administration of fluoxetine with medicinal products that prolong the QT interval, such as Class IA and III antiarrhythmics, antipsychotics") — electronic medicines compendium (UK SmPC)
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 Lumefantrine?
MediHelp rates the interaction as major. Fluoxetine and Lumefantrine 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. Lumefantrine is partly metabolised by CYP2D6 and can prolong the QT interval. Fluoxetine inhibits CYP2D6 and may itself lengthen QT, so combined use may increase the risk of arrhythmia.
How serious is the interaction between Fluoxetine and Lumefantrine?
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 when alternatives exist. Otherwise obtain a baseline ECG, correct potassium and magnesium, and monitor QTc.
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.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
