Drug Interaction Report

Griseofulvin may reduce the blood levels of tofacitinib, which may make the medication less effective in treating your condition. Contact your doctor if your symptoms worsen or your condition changes during treatment with these medications. Your doctor may be able to prescribe alternatives that do not interact, or you may need a dose adjustment or more frequent monitoring to safely use both medications. 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.

You may be advised to take griseofulvin with a fatty meal to increase its absorption into your body. This will make it easier for your body to absorb the medication. The combination of alcohol and griseofulvin may cause flushing and a fast heart rate. Use alcohol cautiously during treatment with griseofulvin.

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.