Drug interactions
Mifepristone + Pimozide
Severity: Contraindicated
Mifepristone and Pimozide: contraindicated 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
Mifepristone inhibits CYP3A4 and can prolong the QT interval, while pimozide is a narrow therapeutic index CYP3A4 substrate that causes dose-related QT prolongation. Combined, pimozide exposure and arrhythmia risk are raised, including torsades de pointes.
What this interaction means in plain words
Mifepristone and Pimozide are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two.
Mifepristone belongs to Endocrine; Pimozide belongs to Central Nervous System.
Why it happens
CYP3A4 inhibition by mifepristone raises pimozide levels, adding to additive QT prolongation.
What to do
Do not use together. Use an alternative to pimozide if mifepristone therapy is needed.
What to ask your pharmacist
- Is there an alternative to one of these two medicines for me?
- If both are essential, who is monitoring me and how often?
- Which symptoms mean I should stop and seek help straight away?
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References
Other interactions of Pimozide
- Adagrasib + Pimozide Contraindicated
- Amiodarone + Pimozide Contraindicated
- Amisulpride + Pimozide Contraindicated
- Amitriptyline + Pimozide Contraindicated
- Amoxapine + Pimozide Contraindicated
- Anagrelide + Pimozide 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 Mifepristone with Pimozide?
MediHelp rates the interaction as contraindicated. Mifepristone and Pimozide are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two. Mifepristone inhibits CYP3A4 and can prolong the QT interval, while pimozide is a narrow therapeutic index CYP3A4 substrate that causes dose-related QT prolongation. Combined, pimozide exposure and arrhythmia risk are raised, including torsades de pointes.
How serious is the interaction between Mifepristone and Pimozide?
MediHelp rates it contraindicated, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Do not use together. Use an alternative to pimozide if mifepristone therapy is needed.
What other medicines interact with Pimozide?
MediHelp also lists interactions of Pimozide with, for example, Adagrasib, Amiodarone, Amisulpride. The full list is on the Pimozide page.
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