Drug interactions
Mifepristone + Nelfinavir
Severity: Major
Mifepristone and Nelfinavir: 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
Nelfinavir is a strong CYP3A4 inhibitor and substrate, and mifepristone also inhibits CYP3A4, so exposure to both may rise. Higher mifepristone levels increase the risk of hypokalemia, adrenal insufficiency and QT prolongation, while higher nelfinavir levels increase its adverse effects.
What this interaction means in plain words
Mifepristone and Nelfinavir 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.
Mifepristone belongs to Endocrine; Nelfinavir belongs to Anti Virals.
Why it happens
Reciprocal CYP3A4 inhibition reduces clearance of both drugs.
What to do
Limit mifepristone to 300 mg/day in Cushing syndrome and monitor potassium and ECG. Monitor for nelfinavir toxicity and consider an alternative antiretroviral.
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 Mifepristone
- Apixaban + Mifepristone Contraindicated
- Argatroban + Mifepristone Contraindicated
- Cisapride + Mifepristone Contraindicated
- Cortisone + Mifepristone Contraindicated
- Cyclosporin + Mifepristone Contraindicated
- Dabigatran etexilate + Mifepristone Contraindicated
Other interactions of Nelfinavir
- Alfuzosin + Nelfinavir Contraindicated
- Avanafil + Nelfinavir Contraindicated
- Dronedarone + Nelfinavir Contraindicated
- Eletriptan + Nelfinavir Contraindicated
- Ergotamine + Nelfinavir Contraindicated
- Flibanserin + Nelfinavir Contraindicated
Frequently asked questions
Can I take Mifepristone with Nelfinavir?
MediHelp rates the interaction as major. Mifepristone and Nelfinavir 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. Nelfinavir is a strong CYP3A4 inhibitor and substrate, and mifepristone also inhibits CYP3A4, so exposure to both may rise. Higher mifepristone levels increase the risk of hypokalemia, adrenal insufficiency and QT prolongation, while higher nelfinavir levels increase its adverse effects.
How serious is the interaction between Mifepristone and Nelfinavir?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Limit mifepristone to 300 mg/day in Cushing syndrome and monitor potassium and ECG. Monitor for nelfinavir toxicity and consider an alternative antiretroviral.
What other medicines interact with Mifepristone?
MediHelp also lists interactions of Mifepristone with, for example, Apixaban, Argatroban, Cisapride. The full list is on the Mifepristone page.
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