OBJECT DRUGS

• Mifepristone (Korlym)

PRECIPITANT DRUGS

Antimicrobials:

• Ciprofloxacin (Cipro, etc.)
• Clarithromycin (Biaxin, etc.)
• Erythromycin (E-Mycin, etc.)
• Fluconazole (Diflucan)
• Itraconazole (Sporanox, etc.)
• Ketoconazole (Nizoral, etc.)
• Posaconazole (Noxafil)
• Quinupristin (Synercid)
• Telithromycin (Ketek)
• Troleandomycin (TAO)
• Voriconazole (Vfend)

Comment:

Inhibitors of CYP3A4 may increase the serum concentrations of mifepristone. The product information for mifepristone states that strong CYP3A4 inhibitors should be used only with "extreme caution" in patients on mifepristone.

Class 2: Use only if Benefit Felt to Outweigh Risk

• Use Alternative:
• Azole Antifungals: Fluconazole appears to be a weaker inhibitor of CYP3A4 than itraconazole or ketoconazole. In larger doses it may inhibit CYP3A4 and should be used cautiously with mifepristone. Single doses of fluconazole would be unlikely to increase the risk of mifepristone toxicity. Terbinafine (Lamisil) does not appear to inhibit CYP3A4.
• Macrolides: Unlike other macrolides, azithromycin (Zithromax) and dirithromycin* do not appear to inhibit CYP3A4 and would not be expected to interact with mifepristone. (*not available in US)
• Telithromycin: The use of azithromycin (Zithromax) or a quinolone antibiotic should be considered.
• Circumvent/Minimize: In patients receiving strong CYP3A4 inhibitors the product information states that the mifepristone dose should be no higher than 300 mg daily.
• Monitor: Monitor for altered mifepristone effect if CYP3A4 inhibitors are initiated, discontinued, or changed in dosage. Adjustments in mifepristone dosage may be necessary.