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 use of alcohol while being treated with busPIRone. Alcohol can increase the nervous system side effects of busPIRone such as dizziness, drowsiness, and difficulty concentrating. Some people may also experience impairment in thinking and judgment. Patients receiving busPIRone should preferably avoid the consumption of large amounts of grapefruits and grapefruit juice. If this is not possible, the busPIRone dose should be taken at least 2 hours before or 8 hours after grapefruit or grapefruit juice. Large amounts of grapefruit and grapefruit juice may cause increased levels of busPIRone in your body. This can lead to increased adverse effects such as drowsiness. Talk to your doctor or pharmacist if you have any questions or concerns.