Xanthine Oxidase Substrate Drugs
ULORIC is an XO inhibitor. Drug interaction studies of ULORIC with drugs that are metabolized by XO (e.g., theophylline, mercaptopurine, azathioprine) have not been conducted. Inhibition of XO by ULORIC may cause increased plasma concentrations of these drugs leading to toxicity [see Clinical Pharmacology]. ULORIC is contraindicated in patients being treated with azathioprine, mercaptopurine, or theophylline [see Contraindications (4) ].
Cytotoxic Chemotherapy Drugs
Drug interaction studies of ULORIC with cytotoxic chemotherapy have not been conducted. No data are available regarding the safety of ULORIC during cytotoxic chemotherapy.
In Vivo Drug Interaction Studies
Based on drug interaction studies in healthy subjects, ULORIC does not have clinically significant interactions with colchicine, naproxen, indomethacin, hydrochlorothiazide, warfarin or desipramine [see Clinical Pharmacology]. Therefore, ULORIC may be used concomitantly with these medications.