Drug Interaction Report

Consumer information for this interaction is not currently available.

MONITOR: Coadministration with phenylbutyrate/taurursodiol (ursodoxicoltaurine) may increase the plasma concentrations of drugs that are substrates of CYP450 2C19, 2C8, 2C9, 2D6, P-glycoprotein (P-gp), breast cancer resistance protein (BCRP), and/or organic anion transporter 1 (OAT1). Clinical and pharmacokinetic data are currently lacking.

MANAGEMENT: Caution is advised if phenylbutyrate/taurursodiol is used concomitantly with substrates of CYP450 2C19, 2C8, 2C9, 2D6, P-gp, BCRP, and/or OAT1, particularly sensitive substrates or those with a narrow therapeutic range. The prescribing information for taurursodiol combined with sodium phenylbutyrate recommends avoiding coadministration with substrates of these isoenzymes and transporters for which minimal concentration changes may lead to therapeutic failure or serious toxicities. If coadministration is required, dosage adjustments as well as clinical and laboratory monitoring may be appropriate whenever phenylbutyrate/taurursodiol is added to or withdrawn from therapy. The prescribing information for concomitant medications should be consulted to assess the benefits versus risks of coadministration and for any dosage adjustments that may be required.

Food may affect the absorption of sodium phenylbutyrate. A high-fat, high-calorie meal (approximately 800 to 1000 calories; 500 to 600 calories from fat, 250 calories from carbohydrate, 150 calories from protein) has been shown to reduce the absorption of sodium phenylbutyrate, although it is unknown what impact this may have on the overall effectiveness of the medication. The manufacturer recommends taking sodium phenylbutyrate before a meal or snack. This is especially important if you weigh less than 70 kg (approximately 154 pounds). Talk to your doctor or pharmacist if you have questions on how to take this or other medications you are prescribed. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medication without first talking to your doctor.