Drug interactions
Fenfluramine + Paroxetine
Severity: Major
Fenfluramine and Paroxetine: major 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
Fenfluramine increases serotonin release and paroxetine blocks its reuptake, so together they raise the risk of serotonin syndrome. Paroxetine also inhibits CYP2D6, which contributes to fenfluramine metabolism.
What this interaction means in plain words
Fenfluramine and Paroxetine 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.
Fenfluramine belongs to Central Nervous System; Paroxetine belongs to Central Nervous System.
Why it happens
Additive serotonergic activity with minor CYP2D6 inhibition.
What to do
Avoid combining where possible. If used together, monitor for serotonin syndrome features such as agitation, tremor, clonus and hyperthermia, and stop one agent if they occur.
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 Fenfluramine and Paroxetine, 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 14 days on the web. No card needed.
Other interactions of Paroxetine
- Isocarboxazid + Paroxetine Contraindicated
- Methylene blue + Paroxetine Contraindicated
- Paroxetine + Phenelzine Contraindicated
- Paroxetine + Pimozide Contraindicated
- Paroxetine + Procarbazine Contraindicated
- Paroxetine + Selegiline Contraindicated
Other interactions of Fenfluramine
- Fenfluramine + Isocarboxazid Contraindicated
- Fenfluramine + Linezolid Contraindicated
- Fenfluramine + Phenelzine Contraindicated
- Fenfluramine + Selegiline Contraindicated
- Fenfluramine + Tranylcypromine Contraindicated
- Almotriptan + Fenfluramine Major
Frequently asked questions
Can I take Fenfluramine with Paroxetine?
MediHelp rates the interaction as major. Fenfluramine and Paroxetine 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. Fenfluramine increases serotonin release and paroxetine blocks its reuptake, so together they raise the risk of serotonin syndrome. Paroxetine also inhibits CYP2D6, which contributes to fenfluramine metabolism.
How serious is the interaction between Fenfluramine and Paroxetine?
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 combining where possible. If used together, monitor for serotonin syndrome features such as agitation, tremor, clonus and hyperthermia, and stop one agent if they occur.
What other medicines interact with Paroxetine?
MediHelp also lists interactions of Paroxetine with, for example, Isocarboxazid, Methylene blue, Phenelzine. The full list is on the Paroxetine 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.
