Pegloticase used in treatment of gout acts by which of the following mechanism:
**Core Concept**
Pegloticase is a recombinant uricase enzyme used in the treatment of severe gout. It works by catalyzing the oxidation of hypoxanthine and xanthine to allantoin, which is more soluble in urine than uric acid, thereby reducing serum uric acid levels.
**Why the Correct Answer is Right**
Pegloticase acts by mimicking the natural uricase enzyme, which is usually deficient or non-functional in patients with gout. This enzyme catalyzes the conversion of hypoxanthine and xanthine to allantoin, which is then excreted in the urine. This process reduces the levels of uric acid in the blood, thereby alleviating the symptoms of gout. Pegloticase is particularly useful in patients with severe gout who have not responded to conventional treatments.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because pegloticase does not inhibit xanthine oxidase, unlike allopurinol which is another drug used to treat gout.
**Option B:** This option is incorrect because pegloticase does not block the reabsorption of uric acid in the kidneys, unlike probenecid which is a uricosuric agent used to treat gout.
**Option C:** This option is incorrect because pegloticase does not decrease the production of uric acid in the body, unlike febuxostat which is a xanthine oxidase inhibitor used to treat gout.
**Clinical Pearl / High-Yield Fact**
Pegloticase is a recombinant enzyme that is derived from the bacterium Klebsiella pneumoniae. It is administered intravenously and is typically used in patients with severe gout who have not responded to conventional treatments.
**Correct Answer:** C. Catalyzing the oxidation of hypoxanthine and xanthine to allantoin.