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Drug interactions

Erythromycin + Mifepristone

Severity: Major

Erythromycin 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

Mifepristone inhibits CYP3A4 and may raise erythromycin exposure. Both agents can prolong the QT interval, which adds to arrhythmia risk.

What this interaction means in plain words

Erythromycin 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.

Erythromycin belongs to Anti Bacterial; Mifepristone belongs to Endocrine.

Evidence level: Moderate

Why it happens

Mifepristone inhibits CYP3A4, and both drugs have additive QT-prolonging potential.

What to do

Avoid the combination where possible, especially with prolonged mifepristone therapy. If necessary, check an ECG and electrolytes and monitor for erythromycin toxicity.

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?

Bring a full list of your medicines, including over-the-counter products, supplements and herbal remedies, to every pharmacy visit.

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Frequently asked questions

Can I take Erythromycin with Mifepristone?

MediHelp rates the interaction as major. Erythromycin 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. Mifepristone inhibits CYP3A4 and may raise erythromycin exposure. Both agents can prolong the QT interval, which adds to arrhythmia risk.

How serious is the interaction between Erythromycin 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: Avoid the combination where possible, especially with prolonged mifepristone therapy. If necessary, check an ECG and electrolytes and monitor for erythromycin toxicity.

What other medicines interact with Erythromycin?

MediHelp also lists interactions of Erythromycin with, for example, Conivaptan, Dihydroergotamine intranasal, Dihydroergotamine. The full list is on the Erythromycin page.

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