Deflazacort and Mifepristone interaction
Deflazacort and Mifepristone: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Mifepristone label · effective 2025-09-25
WARNING: TERMINATION OF PREGNANCY Mifepristone is a potent antagonist of progesterone and cortisol via the progesterone and glucocorticoid (GR-II) receptors, respectively.
…ergotamine, fentanyl, pimozide, quinidine, sirolimus, and tacrolimus, due to an increased risk of adverse events. [See Drug Interactions ( 7.1 ) and Clinical Pharmacology ( 12.3 )] Patients receiving systemic corticosteroids for lifesaving purposes (e.g., immunosuppression after organ transplantation) because mifepristone antagonizes the effect of glucocorticoids.
Patients receiving systemic corticosteroids for lifesaving purposes ( 4 )
For medical conditions in which chronic corticosteroid therapy is lifesaving (e.g., immunosuppression in organ transplantation), mifepristone is contraindicated. [See Contraindications (4.3)] 5.6 Use of Strong CYP3A Inhibitors Mifepristone should be used with caution in patients taking ketoconazole and other strong inhibitors of CYP3A, such as itraconazole, nefazodone,…
High doses of supplemental glucocorticoids may be needed to overcome the glucocorticoid receptor blockade produced by mifepristone.
From the Deflazacort (EMFLAZA) label · effective 2025-11-13
Moderate or strong CYP3A4 inhibitors: Give one third of the recommended dosage of EMFLAZA ( 7.1 )
Co-administration of deflazacort with clarithromycin, a strong CYP3A4 inhibitor, increased total exposure to 21-desDFZ by about 3-fold.
Therefore, give one third the recommended dosage of EMFLAZA when moderate or strong CYP3A4 inhibitors (e.g., clarithromycin, fluconazole, diltiazem, verapamil, grapefruit juice) are used concomitantly with EMFLAZA [see Dosage and Administration ( 2.5 ) and Clinical Pharmacology ( 12.3 )] .
CYP3A4 Inhibitors and Inducers Moderate or Strong CYP3A4 Inhibitors The active metabolite of deflazacort, 21-desDFZ, is a substrate of CYP3A4 [see Clinical Pharmacology ( 12.3 )] .
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Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.