OBJECT DRUGS

• Mifepristone (Korlym)

PRECIPITANT DRUGS

Enzyme Inducers:

• Barbiturates
• Bosentan (Tracleer)
• Carbamazepine (Tegretol, etc.)
• Dabrafenib (Tafinlar)
• Dexamethasone (Decadron, etc.)
• Efavirenz (Sustiva)
• Lumacaftor (Orkambi)
• Nevirapine (Viramune, etc.)
• Oxcarbazepine (Trileptal, etc.)
• Phenytoin (Dilantin, etc.)
• Primidone (Mysoline)
• Rifabutin (Mycobutin)
• Rifampin (Rifadin, etc.)
• Rifapentine (Priftin)
• St. John's wort

Comment:

Mifepristone is metabolized by CYP3A4, and enzyme inducers may reduce serum concentrations of mifepristone. The product information for mifepristone states that enzyme inducers should not be administered with mifepristone therapy.

Class 2: Use only if Benefit Felt to Outweigh Risk

• Use Alternative:
• Anticonvulsants: In patients on mifepristone it would be desirable to use anticonvulsants that are not enzyme inducers, but in many cases it may not be reasonable to change the patient's anticonvulsant regimen.
• HIV Medications. Since most antiviral medications are either inducers or inhibitors, it is probably best just to monitor patients and adjust mifepristone doses as needed.
• St. John's wort: Given the questionable benefit of St. John's wort, it would be prudent to avoid giving it with mifepristone.
• Monitor: Monitor for altered mifepristone effect if enzyme inducers are initiated, discontinued, or changed in dosage. Adjustments in mifepristone dosage may be necessary. Keep in mind that enzyme induction is usually gradual and may take days to weeks for onset and offset, depending on the specific inducer.