Drug interactions
Fluoxetine + Lorcaserin
Severity: Major
Fluoxetine and Lorcaserin: 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
Lorcaserin is a serotonin 5-HT2C agonist, and combining it with an SSRI may increase the risk of serotonin syndrome. Lorcaserin has been withdrawn from the US market, but the interaction remains relevant where it is still available.
What this interaction means in plain words
Fluoxetine and Lorcaserin 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 effects; fluoxetine also inhibits CYP2D6, which contributes to lorcaserin metabolism.
What to do
Avoid the combination if possible. If used, monitor for serotonin syndrome symptoms.
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
Frequently asked questions
Can I take Fluoxetine with Lorcaserin?
MediHelp rates the interaction as major. Fluoxetine and Lorcaserin 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. Lorcaserin is a serotonin 5-HT2C agonist, and combining it with an SSRI may increase the risk of serotonin syndrome. Lorcaserin has been withdrawn from the US market, but the interaction remains relevant where it is still available.
How serious is the interaction between Fluoxetine and Lorcaserin?
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 if possible. If used, monitor for serotonin syndrome symptoms.
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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