Probenecid

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Summary

Probenecid is a drug used to treat chronic gout. It works by inhibiting uric acid reabsorption in the kidney, increasing the amount of uric acid that is lost in the urine. Note that while probenecid is indicated for treating chronic gout, it is not used for treating acute gouty flares as levels of circulating uric acid may temporarily increase shortly after administration.  Probenecid may also increase penicillin levels in the blood by blocking its renal excretion. Side effects of increasing uric acid excretion in the urine include an increased risk of developing uric acid stones.

Key Points

  • Probenecid
    • Mechanism
      • Increased excretion of uric acid in urine (uricosuric)
        • Inhibits reabsorption of uric acid in proximal convoluted tubule
        • Can cause uric acid calculi
          • Avoid in patients with history of uric acid stones
      • Inhibits secretion of penicillin → prolonged penicillin serum levels
    • Clinical Uses
      • Chronic Gout
        • Used in patients with tophi and chronic progressive arthritis
        • Should not be used during acute gout flares as they can exacerbate acute arthritis