Salicylic acid uricosuric agent

Most drugs act by reducing active transport rather than by enhancing it. Thus, drugs that promote uric acid loss (uricosuric agents, such as probenecid and sulfinpyrazone) probably inhibit active urate reabsorption, while pyrazinamide, which reduces urate excretion, may block the active tubular secretion of uric acid. A complicating observation is that a drug may primarily inhibit active reabsorption at one dose and active secretion at another, frequently lower, dose. For example, small amounts of salicylate will decrease total urate ex-... 

Probenecid can impair the renal active secretion of a variety of acidic compounds, including sulfinpyrazone, sulfonylureas, indomethacin, penicillin, sulfonamides, and 17-ketosteroids. If these agents are to be given concomitantly with probenecid, their dosage should be modified appropriately. Salicylates interfere with the clinical effects of both sulfinpyrazone and probenecid and should be avoided in patients treated with uricosuric agents. Uricosuric agents also can influence the volume of distribution and hepatic metabolism of a number of drugs. 

Sulfinpyrazone, a pyrazolidine derivative, is a potent uricosuric agent which also has antithrombotic and platelet inhibitory effects (see Figure 92). It lacks antiinflammatory and analgesic properties. Sulhnpyrazone inhibits renal tubular reabsorption of uric acid. It reduces renal tubular secretion of other organic anions, e.g., paraaminohippuric acid and salicylic acid, and displaces other organic anions bound extensively to plasma proteins (e.g., sulfonamides, salicylates). It is not intended for the relief of an acute attack of gout. 

Low doses (1 or 2 g/day) can decrease urate excretion and elevate plasma urate concentrations intermediate doses (2 or 3 g/day) may not alter urate excretion large doses (more than 5 g/day) induce uricosuria and lower plasma urate levels. However, such large doses are tolerated poorly. Even small doses of salicylate can block the effects 0/probenecid and other uricosuric agents that decrease tubular reabsorption of uric acid. 

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