Management of Hyperuricosuria and Uric‑Acid Stone Risk

Dietary Contributors

High intake of meat and seafood increases purine load and raises 24‑hour urinary uric acid excretion in adults at risk for uric‑acid stones. 1
Consumption of alcohol—particularly beer and distilled spirits—enhances endogenous uric acid production, contributing to hyperuricosuria. 1
Regular consumption of sugar‑sweetened beverages and fructose‑rich foods is associated with higher urinary uric acid levels and increased stone risk. 1

Uricosuric agents such as probenecid, fenofibrate, and losartan deliberately increase urinary uric acid excretion and are used to promote uric acid clearance. [2][3]

In the evaluation of calcium‑oxalate stone formers, a 24‑hour urinary uric acid excretion > 800 mg/day defines hyperuricosuria. [4][5]

The ACR guidelines state that an elevated urinary uric acid level indicating overproduction is a contraindication to initiating uricosuric therapy. [2][3]

AUA guidance emphasizes that low urinary pH is the predominant risk factor for uric‑acid stone formation, outweighing the contribution of elevated urinary uric acid alone. [4][6]

Measure 24‑hour urinary uric acid before starting any uricosuric medication to confirm the presence or absence of overproduction. [2][3]7
Continue periodic urinary uric acid assessments during uricosuric treatment to evaluate therapeutic response and adjust dosing as needed. [2][8]
When hyperuricosuria is documented, adjunctive urine alkalinization with potassium citrate is recommended to reduce stone risk by raising urinary pH. [2][8]
Determining 24‑hour urinary uric acid helps differentiate true overproducers from patients whose stone risk is driven primarily by acidic urine, guiding appropriate management. [2][8]

Probenecid is recommended as the first‑choice uricosuric medication to increase renal uric acid clearance (American College of Rheumatology). 9
Fenofibrate and losartan possess clinically significant uricosuric effects and may be incorporated into comprehensive urate‑lowering strategies (American College of Rheumatology). 9
The American College of Rheumatology advises that elevated urinary uric acid indicating overproduction is a contraindication to initiating uricosuric therapy. 9
Measurement of 24‑hour urinary uric acid should be performed before starting any uricosuric agent to differentiate overproduction from underexcretion (American College of Rheumatology). 9
A history of urolithiasis contraindicates the use of first‑line uricosuric monotherapy (American College of Rheumatology). 9
Urinary uric acid should be monitored periodically during uricosuric treatment to assess therapeutic response (American College of Rheumatology). 9
Adjunctive urine alkalinization with potassium citrate is recommended when hyperuricosuria is documented, as it raises urinary pH and reduces stone risk (American College of Rheumatology). 9

Hyperuricosuria is defined as a 24‑hour urinary uric acid excretion exceeding 1,000 mg/day on a regular diet (Annals of the Rheumatic Diseases). 10
A second source corroborates the >1,000 mg/day threshold for overexcretion (Annals of the Rheumatic Diseases). 11

Tumor lysis syndrome releases large amounts of intracellular nucleic acids that are catabolized to uric acid; the normal renal clearance of approximately 500 mg/day is overwhelmed, leading to marked hyperuricosuria (Journal of Clinical Oncology). 12