Drug Interactions between ifosfamide and upadacitinib

GENERALLY AVOID: Grapefruit, grapefruit juice or supplements containing grapefruit may increase the plasma concentrations of upadacitinib. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in these fruits. Inhibition of hepatic CYP450 3A4 may also contribute. The interaction has not been studied with grapefruit. In study subjects, administration with the potent CYP450 3A4 inhibitor ketoconazole increased upadacitinib peak plasma concentration (Cmax) and systemic exposure (AUC) by 70% and 75%, respectively. In general, the effect of grapefruit juice is concentration-, dose- and preparation-dependent, and can vary widely among brands. Certain preparations of grapefruit juice (e.g., high dose, double strength) have sometimes demonstrated potent inhibition of CYP450 3A4, while other preparations (e.g., low dose, single strength) have typically demonstrated moderate inhibition. Upadacitinib side effects including lymphopenia, neutropenia, anemia, serious infections, and hyperlipidemia may be increased.

MONITOR CLOSELY: Smoking during treatment with upadacitinib may increase the risk of major adverse cardiovascular events (MACE) and the risk of developing malignancies. During upadacitinib clinical studies, current or past smokers had an additional increased risk of overall malignancies. Also, upadacitinib may increase patients' risk of MACE, including myocardial infarction, stroke, and cardiovascular death.

MANAGEMENT: The manufacturer advises that concomitant use of upadacitinib with grapefruit, grapefruit juice, or supplements containing grapefruit should be avoided. Caution is advised if upadacitinib is prescribed to current or past smokers. Patients should be informed about the symptoms of serious cardiovascular events and the steps to take if they occur. The manufacturer recommends discontinuing upadacitinib in patients who have experienced a myocardial infarction or stroke.

GENERALLY AVOID: Grapefruit and/or grapefruit juice may reduce the efficacy of ifosfamide, whose anticancer effect is dependent on its activation to the 4-hydroxyifosfamide metabolite via CYP450 3A4. The proposed mechanism is inhibition of CYP450 3A4 metabolism by certain compounds present in grapefruit. There are no data available about the effects of grapefruit on ifosfamide. However, in a small study, 8 patients with incurable malignancies received ifosfamide 3 g/m2 by infusion with the potent CYP450 3A4 inhibitor ketoconazole 200 mg orally twice daily for 4 days starting 1 day before the ifosfamide infusion. Ketoconazole decreased the clearance of ifosfamide by 11%, decreased systemic exposure (AUC) of the active metabolite 4-hydroxyifosfamide by 30%, and increased the AUC of the inactive but potentially neurotoxic metabolite 2-dechloroethylifosfamide by 23%, as compared to control. Because pharmacokinetic interactions involving grapefruit juice are often subject to a high degree of interpatient variability, the extent to which a given patient may be affected is difficult to predict.

GENERALLY AVOID: Alcohol may potentiate the neurotoxic effects of ifosfamide. Use in combination may result in additive central nervous system depression and/or impairment of judgment, thinking, and psychomotor skills. In addition, ifosfamide therapy may cause gastrointestinal disorders and alcohol consumption may increase nausea and vomiting.

MANAGEMENT: Given the potential for reduced efficacy of ifosfamide and increased risk of neurotoxicity and nephrotoxicity it may be advisable for patients to avoid consumption of grapefruit, grapefruit juice, or supplements that contain grapefruit during treatment with ifosfamide. In addition, patients receiving ifosfamide should be warned of the increased risk of neurotoxicity, nausea and vomiting when used in combination with alcohol. Patients should avoid or limit the consumption of alcohol during treatment with ifosfamide.