indication

For the treatment of gout and gouty arthritis.

pharmacology

Sulfinpyrazone's pharmacologic activity is the potentiation of the urinary excretion of uric acid. It is useful for reducing the blood urate levels in patients with chronic tophaceous gout and acute intermittent gout, and for promoting the resorption of tophi.

mechanism of action

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).

toxicity

Symptoms of overdose include nausea, vomiting, diarrhea, epigastric pain, ataxia, labored respiration, convulsions, coma. Possible symptoms, seen after overdosage with other pyrazolone derivatives: anemia, jaundice, and ulceration.

half life

Approximately 4-6 hours

drug interactions

Cyclosporine: Sulfinpyrazone decreases the effect of cyclosporine

Tolbutamide: Tolbutamide, a strong CYP2C9 inhibitor, may decrease the metabolism and clearance of Sulfinpyrazone. Consider alternate therapy or monitor for changes in Sulfinpyrazone therapeutic and adverse effects if Tolbutamide is initiated, discontinued or dose changed.

Warfarin: Sulfinpyrazone may increase the anticoagulant effect of warfarin by decreasing its metabolism and protein binding.