Drug interactions
Fluoxetine + Mifepristone
Severity: Major
Fluoxetine and Mifepristone: 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
Both drugs can prolong the QT interval, and mifepristone at higher doses (such as for Cushing syndrome) also inhibits CYP3A4 and may raise fluoxetine exposure. This increases the risk of torsades de pointes in susceptible patients.
What this interaction means in plain words
Fluoxetine and Mifepristone 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.
Fluoxetine belongs to Central Nervous System; Mifepristone belongs to Endocrine.
Why it happens
Additive QT prolongation, with possible increased fluoxetine exposure through enzyme inhibition by mifepristone.
What to do
Use an alternative antidepressant if feasible; if combined, obtain a baseline ECG, monitor QTc and correct potassium and magnesium.
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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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 Mifepristone
- Apixaban + Mifepristone Contraindicated
- Argatroban + Mifepristone Contraindicated
- Cisapride + Mifepristone Contraindicated
- Cortisone + Mifepristone Contraindicated
- Cyclosporin + Mifepristone Contraindicated
- Dabigatran etexilate + Mifepristone Contraindicated
Frequently asked questions
Can I take Fluoxetine with Mifepristone?
MediHelp rates the interaction as major. Fluoxetine and Mifepristone 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. Both drugs can prolong the QT interval, and mifepristone at higher doses (such as for Cushing syndrome) also inhibits CYP3A4 and may raise fluoxetine exposure. This increases the risk of torsades de pointes in susceptible patients.
How serious is the interaction between Fluoxetine and Mifepristone?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Use an alternative antidepressant if feasible; if combined, obtain a baseline ECG, monitor QTc and correct potassium and magnesium.
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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