Drug Interaction Report

GENERALLY AVOID: Salicylates may antagonize the uricosuric effect of sulfinpyrazone. The exact mechanism of interaction is unknown, although therapeutic doses of aspirin have been shown to increase plasma clearance of sulfinpyrazone. In one study, acute pretreatment with aspirin (325 mg four times a day for 24 hours) resulted in increased plasma clearance of a single 400 mg dose of sulfinpyrazone in 5 of 6 subjects by 12% to 27% relative to administration of sulfinpyrazone alone. When sulfinpyrazone 200 mg and aspirin 325 mg were coadministered four times a day for one week, plasma clearance of sulfinpyrazone increased up to 229%. The investigators theorized that aspirin may displace sulfinpyrazone from plasma protein binding sites, resulting in a redistribution of sulfinpyrazone into peripheral compartments and increased amount of free drug for hepatic metabolism. In vitro data also suggest that sulfinpyrazone may interfere with the irreversible effects of aspirin (especially low doses) on platelets, although the clinical significance is unknown.

MANAGEMENT: Salicylates should not be used during sulfinpyrazone therapy for gouty arthritis. However, occasional small doses of salicylates are not expected to interact significantly.