It is especially important to tell your doctor or pharmacist if you are taking medicines containing any of the following substances as they may interact with ADENURIC and your doctor may wish to consider necessary measures: • Mercaptopurine (used to treat cancer) • Azathioprine (used to reduce immune response) • Theophylline (used to treat asthma) • Warfarin (used to thin your blood if you have a heart condition)