Drug Interaction Report

ADDITIONAL CONTRACEPTION RECOMMENDED: Coadministration with lesinurad may decrease the plasma concentrations of contraceptive hormones and reduce their effectiveness. The interaction has not been evaluated in pharmacokinetic studies. However, lesinurad is a weak inducer of CYP450 3A4, the isoenzyme responsible for the metabolic clearance of contraceptive hormones. Lesinurad has been shown to induce the metabolism of other CYP450 3A4 substrates in interaction studies.

MANAGEMENT: Hormonal contraceptives, including oral, injectable, transdermal, and implantable forms, may not be reliable when used with lesinurad. Female patients of reproductive potential receiving hormonal contraceptives should practice additional methods of contraception during treatment with lesinurad.

ADJUST DOSING INTERVAL: The tolerability of allopurinol may be improved by giving it after a meal. Additionally, when the dose is greater than 300 mg, dividing the total daily dose into smaller doses administered more often may be appropriate to help minimize gastrointestinal irritation.

MONITOR: Concomitant use of allopurinol with central nervous system (CNS) depressants, including alcohol, may potentiate adverse effects such as somnolence and sedation.

MANAGEMENT: To improve tolerability, some manufacturers suggest administering allopurinol after a meal. Additionally, if the daily dose is greater than 300 mg, administering allopurinol in divided doses may help reduce gastrointestinal intolerance. Patients should also be counseled to avoid or limit consumption of alcohol and to avoid activities requiring mental alertness such as driving or operating hazardous machinery until they know how the medication affects them.