Drug interactions
Dexfenfluramine + Duloxetine
Severity: Major
Dexfenfluramine and Duloxetine: 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
Dexfenfluramine releases serotonin and blocks its reuptake, and duloxetine also raises synaptic serotonin. The combination increases the risk of serotonin syndrome, with agitation, tremor, hyperthermia and neuromuscular hyperactivity. Dexfenfluramine has been withdrawn from most markets.
What this interaction means in plain words
Dexfenfluramine and Duloxetine 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
Additive serotonergic activity through serotonin release and reuptake inhibition.
What to do
Avoid the combination where possible. If it is unavoidable, monitor for signs of serotonin syndrome and stop one or both agents if symptoms appear.
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 Duloxetine
- Duloxetine + Isocarboxazid Contraindicated
- Duloxetine + Linezolid Contraindicated
- Duloxetine + Methylene blue Contraindicated
- Duloxetine + Phenelzine Contraindicated
- Duloxetine + Procarbazine Contraindicated
- Duloxetine + Rasagiline Contraindicated
Frequently asked questions
Can I take Dexfenfluramine with Duloxetine?
MediHelp rates the interaction as major. Dexfenfluramine and Duloxetine 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. Dexfenfluramine releases serotonin and blocks its reuptake, and duloxetine also raises synaptic serotonin. The combination increases the risk of serotonin syndrome, with agitation, tremor, hyperthermia and neuromuscular hyperactivity. Dexfenfluramine has been withdrawn from most markets.
How serious is the interaction between Dexfenfluramine and Duloxetine?
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. If it is unavoidable, monitor for signs of serotonin syndrome and stop one or both agents if symptoms appear.
What other medicines interact with Duloxetine?
MediHelp also lists interactions of Duloxetine with, for example, Isocarboxazid, Linezolid, Methylene blue. The full list is on the Duloxetine page.
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