DOSES OF SULPHINPYRAZONE MAY NEED TO BE INCREASED IF CONCURRENTLY USED WITH DIURETICS OR PYRAZINAMIDE THAT INCREASE URIC ACID CONCENTRATIONS. SALICYLATES INCLUDING ASPIRIN ARE MUTUALLLLY ANTAGONISTIC. ASPIRIN THAT INHIBIT PLATELET FUNCTIN MAY INCREASE RISK OF BLEEDING. IT CAN INHIBIT THE METABOLISM OF SOME DRUGS LEADING TO AN INCREASE IN THEIR ACTIVITY . THE DRUGS ARE WARFARIN, NICOUMALONE, AND COUMARIN ANTICOAGULANTS. IT MAY POTENTIATE THE EFFECTS OF PHENYTOIN. THE ACTIVITY OF THEOPHYLLINE MAY BE DIMINISHED BY SULPHINPYRAZONE INCREASING ITS METABOLISM.