Drug Interaction Report

Consumer information for this interaction is not currently available.

MONITOR: Coadministration with treosulfan may increase the plasma concentrations of drugs that are substrates of CYP450 3A4, 2C19, and/or the efflux transporter P-glycoprotein (P-gp). The proposed mechanism is decreased clearance due to inhibition of these routes of elimination due to treosulfan. According to physiologically-based pharmacokinetic modeling, treosulfan is predicted to be a weak to moderate CYP450 3A4 inhibitor and weak inhibitor of CYP450 2C19, with negligible inhibitory effects on P-gp. However, according to the manufacturer, in vitro studies were unable to exclude potential drug-drug interactions with high plasma concentrations of treosulfan and CYP450 3A4, 2C19, and/or P-gp substrates.

MANAGEMENT: Caution is recommended if treosulfan is coadministered with substrates of CYP450 3A4, 2C19, and/or P-gp, particularly those with a narrow therapeutic range. Some authorities advise that if concomitant use is required, the dosage of these substrates should be administered either 2 hours before or 8 hours after administration of the treosulfan infusion. The prescribing information of the substrates may be consulted for potential dose reductions.

You should avoid the regular consumption of large amounts of grapefruits and grapefruit juice while taking budesonide. Grapefruit can raise the levels of budesonide in your body and lead to increased side effects. Do not increase or decrease the amount of grapefruit products in your diet without first talking to your doctor.