OBJECT DRUGS

Azole Antifungals:

• Itraconazole (Sporanox, etc.)
• Ketoconazole (Nizoral, etc.)
• Posaconazole (Noxafil)
• Voriconazole (Vfend)

PRECIPITANT DRUGS

Enzyme Inducers:

• Barbiturates
• Bosentan (Tracleer)
• Dexamethasone (Decadron, etc.)
• Carbamazepine (Tegretol, etc.)
• Dabrafenib (Tafinlar)
• 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:

Rifampin, carbamazepine, phenytoin (and probably other enzyme inducers) markedly reduce serum concentrations of these antifungals. Due to the large magnitude of the interaction it may be difficult to achieve therapeutic concentrations of these antifungal agents. The azole antifungals may also affect some of the enzyme inducers. For example, the azole antifungals may markedly increase carbamazepine or rifabutin concentrations, and voriconazole can increase efavirenz concentrations.

Class 3: Assess Risk & Take Action if Necessary

• Consider Alternative:
• Antifungal Agent: Fluconazole (Diflucan) appears less likely to interact than other azole antifungals (because of its extensive renal elimination, it is less affected by enzyme inducers), but some reports suggest that enzyme inducers may also reduce fluconazole efficacy. In one study, rifampin markedly increased the clearance of terbinafine (Lamisil), so it may also interact.
• Monitor:If the ibuprofen, naproxen or indomethacin is only taken once daily or less, giving the NSAID 2 hours after the aspirin would probably minimize the interaction.