Drug interactions
Mifepristone + Thioridazine
Severity: Contraindicated
Mifepristone and Thioridazine: 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 can prolong the QT interval and thioridazine is a well-known cause of torsades de pointes. Using them together raises the risk of serious ventricular arrhythmia. Mifepristone, particularly at the higher doses used for Cushing's syndrome, also inhibits CYP enzymes, which may raise thioridazine levels.
What this interaction means in plain words
Mifepristone and Thioridazine 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; Thioridazine belongs to Central Nervous System.
Why it happens
Additive QT prolongation, with possible CYP2D6/3A4 inhibition by mifepristone increasing thioridazine exposure.
What to do
Avoid concurrent use and select an antipsychotic with minimal QT effect. If mifepristone is essential, review the need for thioridazine and monitor ECG and electrolytes.
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 Thioridazine
- Abiraterone + Thioridazine Contraindicated
- Adagrasib + Thioridazine Contraindicated
- Amiodarone + Thioridazine Contraindicated
- Amisulpride + Thioridazine Contraindicated
- Amitriptyline + Thioridazine Contraindicated
- Amoxapine + Thioridazine 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 Thioridazine?
MediHelp rates the interaction as contraindicated. Mifepristone and Thioridazine 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 can prolong the QT interval and thioridazine is a well-known cause of torsades de pointes. Using them together raises the risk of serious ventricular arrhythmia. Mifepristone, particularly at the higher doses used for Cushing's syndrome, also inhibits CYP enzymes, which may raise thioridazine levels.
How serious is the interaction between Mifepristone and Thioridazine?
MediHelp rates it contraindicated, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid concurrent use and select an antipsychotic with minimal QT effect. If mifepristone is essential, review the need for thioridazine and monitor ECG and electrolytes.
What other medicines interact with Thioridazine?
MediHelp also lists interactions of Thioridazine with, for example, Abiraterone, Adagrasib, Amiodarone. The full list is on the Thioridazine page.
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