The optimal serum urate levels necessary for elimination of tissue deposits of monosodium urate in patients with chronic gout is controversial. This observational, prospective study evaluates the relationship between serum urate levels during therapy and the velocity of reduction of tophi in patients with chronic tophaceous gout.

Sixty-three patients with crystal-confirmed tophaceous gout were treated with allopurinol, benzbromarone, or combined therapy to achieve serum uric acid levels less than the threshold for saturation of urate in tissues. The tophi targeted for evaluation during followup were the largest in diameter found during physical examination.

Patients taking benzbromarone alone or combined allopurinol and benzbromarone therapy achieved faster velocity of reduction of tophi than patients taking allopurinol alone. The velocity of tophi reduction was linearly related to the mean serum urate level during therapy. The lower the serum urate levels, the faster the velocity of tophi reduction.

Serum urate levels should be lowered enough to promote dissolution of urate deposits in patients with tophaceous gout. Allopurinol and benzbromarone are equally effective when optimal serum urate levels are achieved during therapy. Combined therapy may be useful in patients who do not show enough reduction in serum urate levels with single-drug therapy.