Krystexxa (pegloticase) is an enzyme that lowers uric acid levels by converting it into a harmless substance eliminated through urine. It is used in adults to treat gout that is not controlled by other medications. By reducing uric acid buildup, Krystexxa helps prevent the formation of uric acid crystals in joints, kidneys, and other organs, alleviating pain, swelling, and inflammation associated with gout.