Probenecid Clinical Pearls
Probenecid can be used for patients who have gout. The drug lowers uric acid levels which can help prevent future gout flares. While I readily admit that probenecid is not used very often, it does come with some unique quirks that you should be able to recognize in the odd chance it is used. Here my list of probenecid clinical pearls that you should be aware of.
G6PD deficiency can increase the risk of hemolytic anemia in patients who take probenecid. Because of this risk, CBC monitoring is recommended and is absolutely essential in patients who may be displaying signs or symptoms of hemolytic anemia. Remember that patients at higher risk for G6PD deficiency include males, Middle-Eastern or African descent, or patients who have a family history.
Probenecid is uniquely different from allopurinol in its mechanism of action. It works by essentially blocking the kidney from reabsorbing uric acid. This enhances elimination from the body. This can ultimately lower levels and reduce the frequency and severity of gout exacerbations. If you recall from my recent podcast episode, allopurinol works on the production side by preventing the formation of uric acid.
Because probenecid works in certain areas of the kidney where reabsorption of medications happens, it can impact some drugs that are renally eliminated. Penicillin antibiotics, cephalosporins, methotrexate, NSAIDs, nitrofurantoin, and loop diuretics are all common examples of medications that could have their concentrations increased on account of probenecid. When it comes to drug interactions, also keep an eye out for drugs that can raise uric acid and oppose the beneficial effects.
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In geriatrics, one of the most important probenecid clinical pearls to remember is that as renal function declines, this drug will likely be less effective. Probenecid relies on the function of the kidney to alter the elimination pattern of uric acid. If that kidney is not working correctly, the drug will not work effectively.