Sulfinpyrazone was approved by the U.S. Food and Drug Administration (FDA) on May 13, 1959. It was developed and marketed as Anturane® by Novartis. Sulfinpyrazone is an oral uricosuric agent (pyrazolone derivative) used to treat chronic or intermittent gouty arthritis. Sulfinpyrazone competitively inhibits the reabsorption of uric acid at the proximal convoluted tubule, thereby facilitating urinary excretion of uric acid and decreasing plasma urate concentrations. This is likely done through inhibition of the urate anion transporter (hURAT1) as well as the human organic anion transporter 4 (hOAT4). Sulfinpyrazone is not intended for the treatment of acute attacks because it lacks therapeutically useful analgesic and anti-inflammatory effects. Sulfinpyrazone and its sulfide metabolite possess COX inhibitory effects. Sulfinpyrazone has also been shown to be a UDP-glucuronsyltransferase inhibitor and a very potent CYP2C9 inhibitor. Sulfinpyrazone is also known to be a cystic fibrosis transmembrane conductance regulator (CFTR) inhibitor as well as an inhibitor of several multridrug resistance proteins (MRPs). Branded and generic forms of sulfinpyrazone have been discontinued in the US.