Drug Interactions between repotrectinib and tofacitinib

Consumption of grapefruit, grapefruit juice, and supplements that contain grapefruit should be avoided during treatment with repotrectinib as they may increase the blood levels of repotrectinib. This may increase the risk and/or severity of side effects such as dizziness, tiredness, muscle pain, nausea, change in your sense of taste, feeling numbness or tingling in your arms or legs, constipation, trouble with balance, shortness of breath, problems with thinking such as forgetfulness or confusion and hallucinations, as well as more serious side effects such severe or life-threatening inflammation of the lungs and liver injury. Talk to your doctor if you have any questions or concerns. Your doctor may be able to provide alternatives that do not interact. 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.

Consumer information for this interaction is not currently available.

MONITOR: Grapefruit juice may increase the plasma concentrations of tofacitinib. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruits. The extent and clinical significance are unknown. Moreover, pharmacokinetic alterations associated with interactions involving grapefruit juice are often subject to a high degree of interpatient variability.

MANAGEMENT: Until more information is available, some authorities recommend avoiding consumption of grapefruit juice during tofacitinib therapy (Canada). Patients receiving tofacitinib therapy who ingest grapefruits or grapefruit juice should be monitored for adverse effects and undue fluctuations in plasma drug levels.