Drug Interaction Report

Consumer information for this interaction is not currently available.

GENERALLY AVOID: Coadministration with moderate inducers of CYP450 3A4 may significantly decrease the plasma concentrations of zanubrutinib, which is primarily metabolized by the isoenzyme. When zanubrutinib was coadministered with multiple doses of rifabutin, a moderate CYP450 3A4 inducer, zanubrutinib plasma concentration (Cmax) and systemic exposure (AUC) decreased 48% and 44%, respectively, in healthy volunteers. Based on pharmacokinetic modeling, coadministration with multiple doses of efavirenz, another moderate CYP450 3A4 inducer, is predicted to decrease zanubrutinib Cmax and AUC by 58% and 60%, respectively. Reduction in zanubrutinib plasma concentration may lead to reduced zanubrutinib efficacy.

MANAGEMENT: Concomitant use of zanubrutinib with moderate CYP450 3A4 inducers should generally be avoided. If coadministration is required, some authorities recommend increasing the dosage of zanubrutinib to 320 mg twice daily. Close clinical monitoring for toxicities and altered efficacy is advised. After discontinuation of the moderate CYP450 3A4 inducer it is recommended to resume the previous dosage of zanubrutinib. Additional consultation with individual package labeling, as well as relevant institutional protocols, may be advisable for further guidance.

Grapefruit juice and Seville orange juice can increase the blood levels of zanubrutinib. This may increase side effects such as rash, diarrhea, constipation, cough, hemorrhage, development of other cancers, abnormal heart rhythm, and impaired bone marrow function resulting in low numbers of different types of blood cells. You may also be more likely to develop anemia, bleeding problems, or infections due to low blood cell counts. You should avoid the consumption of Seville oranges, Seville orange juice, grapefruit and grapefruit juice during treatment with zanubrutinib. Be sure to take the medication at approximately the same time(s) everyday to maintain consistent blood levels and effects. Talk to your doctor or pharmacist if you have questions on how to take this or other medications you are prescribed. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.