Which are favorable uricosurics?

• A. Aspirin and Estrogen
• B. Colchicine and Allopurinol
• C. Allopurinol and Probenecid
• D. Indomethacin and Naproxen

Answer: (A)

Uricosurics work by increasing the kidney’s excretion of uric acid, lowering serum urate. They mainly act by reducing the reabsorption of uric acid in the proximal tubule, helping to promote its elimination.

Estrogen increases uric acid clearance by the kidneys, so it has a uricosuric effect. Aspirin can also be uricosuric, but dose matters: salicylates at sufficiently high doses can reduce uric acid reabsorption and increase excretion, though at low doses aspirin tends to decrease uric acid excretion and is not used to treat gout for that reason. Because of this dose-dependent behavior, aspirin is considered a uricosuric only under certain conditions, whereas estrogen consistently has a uricosuric effect.

The other options don’t fit because the drugs involved aren’t uricosurics. Colchicine and Allopurinol are not uricosurics—colchicine is an anti-inflammatory used to treat flares, and allopurinol lowers uric acid by inhibiting its production. Indomethacin and naproxen are NSAIDs, used for pain and inflammation, not to promote uric acid excretion.

So the combination that aligns with a uricosuric effect is aspirin (at the right dose) and estrogen.