OBJECT DRUGS

Chemotherapy agents (CYP3A4 Substrates):

• Abiraterone (Zytiga)
• Anastrozole (Arimidex)
• Aprepitant (Emend)
• Bexarotene (Targretin)
• Bortezomib (Velcade)
• Brentuximab (Adcetris)
• Cabazitaxel (Jevtana)
• Cyclophosphamide (Cytoxan)
• Docetaxel (Taxotere)
• Doxorubicin (Adriamycin)
• Enzalutamide (Xtandi)
• Etoposide (Vepesid)
• Exemestane (Aromasin)
• Ifosfamide (Ifex)
• Ixabepilone (Ixempra)
• Ixazomib (Ninlaro)
• Letrozole (Femara)
• Paclitaxel (Taxol)
• Panobinostat (Farydak)
• Sonidegib (Odomzo)
• Teniposide (Vumon)
• Toremifene (Fareston)
• Trabectedin (Yondelis)
• Venetoclax (Venclexta)

PRECIPITANT DRUGS

Antimicrobials:

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

Comment:

Although data are limited, these antimicrobials may increase the plasma levels of chemotherapy agents. Toxicity will vary with the object drug but neuropathy, myelosuppression, and gastrointestinal toxicity are common. Assume that all CYP3A4 inhibitors interact until proven otherwise.

Class 3: Assess Risk & Take Action if Necessary

• Consider Alternative:
• Azole Antifungals: Fluconazole is usually a weaker inhibitor of CYP3A4 unless large doses are used. Terbinafine (Lamisil) does not appear to affect CYP3A4.
• Macrolide Antibiotics: Azithromycin (Zithromax) does not appear to inhibit CYP3A4 and would be unlikely to interact.
• Monitor: Monitor for altered antineoplastic response if the CYP3A4 inhibitor is initiated, discontinued, or changed in dosage.