Question

Which of the following is a non-purine xanthine oxidase inhibitor used to treat hyperuricemia?

• A. Allopurinol
• B. Probenecid
• C. Febuxostat
• D. Pegloticase

Hint:

Hyperuricemia (high uric acid) is managed either by reducing uric acid production or by increasing its excretion. Xanthine oxidase inhibitors reduce production by blocking the enzyme that converts purines into uric acid.

Answer 1

The Correct Option is C

Step 1: Understanding the question.
The question asks for a non-purine xanthine oxidase inhibitor used to treat hyperuricemia (high uric acid levels). The key word is non-purine.

Step 2: What is xanthine oxidase?
Xanthine oxidase is the enzyme that converts hypoxanthine to xanthine and then xanthine to uric acid. Blocking this enzyme reduces uric acid production and is useful in gout.

Step 3: Evaluate Option 1 - Allopurinol.
Allopurinol is a purine analogue that inhibits xanthine oxidase. It is structurally similar to xanthine (a purine). So it is a purine-type inhibitor, not non-purine.

Step 4: Evaluate Option 3 - Febuxostat.
Febuxostat is a non-purine selective inhibitor of xanthine oxidase. Unlike allopurinol, it does not incorporate into purine metabolism. It is a novel, non-purine heterocyclic compound that inhibits both oxidized and reduced forms of xanthine oxidase. This is the correct answer.

Step 5: Evaluate Option 2 - Probenecid and Option 4 - Pegloticase.
Probenecid is a uricosuric agent - it promotes uric acid excretion in the urine but does not inhibit xanthine oxidase. Pegloticase is a recombinant uricase enzyme that converts uric acid to allantoin. Neither inhibits xanthine oxidase.

Step 6: Conclusion.
Febuxostat is the non-purine xanthine oxidase inhibitor for hyperuricemia.
Answer: Option (3) — Febuxostat