Drug Interaction Report

MONITOR CLOSELY: Concomitant administration of corticosteroids may potentiate the risk of tendinitis and tendon rupture associated with fluoroquinolone treatment. The mechanism is unknown. Tendinitis and tendon rupture have most frequently involved the Achilles tendon, although cases involving the rotator cuff (the shoulder), the hand, the biceps, and the thumb have also been reported. Some have required surgical repair or resulted in prolonged disability. Tendon rupture can occur during or up to several months after completion of fluoroquinolone therapy.

MANAGEMENT: Caution is recommended if fluoroquinolones are prescribed in combination with corticosteroids, particularly in patients with other concomitant risk factors (e.g., age over 60 years; recipient of kidney, heart, and/or lung transplant). Patients should be advised to stop taking the fluoroquinolone, avoid exercise and use of the affected area, and promptly contact their physician if they experience pain, swelling, or inflammation of a tendon. In general, fluoroquinolones should only be used to treat conditions that are proven or strongly suspected to be caused by bacteria and only if the benefits outweigh the risks.

GENERALLY AVOID: Coadministration with potent and moderate inducers of CYP450 3A4 may significantly decrease the plasma concentrations of axitinib, which is primarily metabolized by the isoenzyme. In a study of 40 healthy, nonsmoking, male volunteers, administration of a single 5 mg dose of axitinib on day 8 of treatment with the potent CYP450 3A4 inducer rifampin (600 mg/day for 9 days) resulted in a 71% decrease in mean axitinib peak plasma concentration (Cmax) and 79% decrease in mean systemic exposure. The extent to which other, less potent inducers of CYP450 3A4 may interact with axitinib is unknown.

MANAGEMENT: Concomitant use of axitinib with potent CYP450 3A4 inducers such as apalutamide, carbamazepine, enzalutamide, lumacaftor, mitotane, phenobarbital, phenytoin, rifamycins, and St. John's wort should generally be avoided. Although pharmacokinetic data are lacking, the manufacturer recommends that moderate CYP450 3A4 inducers should also be avoided if possible, including but not limited to bosentan, cenobamate, dabrafenib, dexamethasone, efavirenz, etravirine, lorlatinib, modafinil, nafcillin, pexidartinib, and sotorasib.

GENERALLY AVOID: Grapefruit juice may increase the plasma concentrations of axitinib. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit.

MANAGEMENT: Patients treated with axitinib should avoid consumption of grapefruit, grapefruit juice, and any supplement containing grapefruit extract. Axitinib may be administered with or without food.