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.

Food decreases the levels of erythromycin in your body. Take erythromycin on an empty stomach at least 30 minutes before or 2 hours after a meal. This will make it easier for your body to absorb the medication. However, some erythromycin products may be taken without regard to meals. Ask your healthcare provider about your particular prescription if you are uncertain of how to take it. Grapefruits and grapefruit juice may increase erythromycin levels but how this may affect you is not known. Do not increase or decrease the amount of grapefruit products in your diet without first talking to your doctor.

Information for this minor interaction is available on the professional version.