12. Concomitant administration of any of the following: azathioprine, mercaptopurine, theophylline, meclofenamate, sulfinpyrazone, trimethoprim-sulfamethoxazole, cyclophosphamide, benzbromarone, pyrazinamide, captopril and enalapril (for Allopurinol), tegafur, pegloticase and tacrolimus.