NCT04621929

Phentermine/Topiramate for Uric Acid Stones

Phentermine/tOpiramate to eND Obesity and Uric Acid Stones Trial (POuND OUT)

• Status: Completed
• Phase: Phase 3
• Study type: Interventional
• Enrollment: 19 (actual)
• Sponsor: University of Florida · Academic / Other
• Sex: All
• Age: 18 Years – 75 Years
• Healthy volunteers: Not accepted

Summary

The investigator proposes an 18 month, feasibility pilot study, randomizing obese and diabetic individuals with pure uric acid nephrolithiasis (UAN) or mixed calcium oxalate (CO) UAN to either phentermine/topiramate or a pragmatic control group who will remain on their standard medication regimen (citrate salts, allopurinol, diet, etc.).

Detailed description

Mounting evidence indicates that obesity, diabetes mellitus, and kidney stones are inter-connected diseases, particularly uric acid nephrolithiasis (UAN) with or without components of calcium oxalate (CO). Obese or overweight diabetics have a six-fold increased risk to develop UAN/COUAN due to the inability to properly add buffer (ammonium) to urine. Of the FDA approved drugs in the weight loss market, the combination medication phentermine/ topiramate is the most effective and has a unique side effect of alkalinizing the urine (making it less acidic). The hypothesize of this project is that treatment of obese, diabetic patients with phentermine/topiramate will reduce the incidence of UAN/COUAN by 1) direct urinary alkalinization and 2) weight loss. Weight loss will indirectly improve urinary buffering ability through improvement in insulin sensitivity and will decrease renal oxidative stress. The investigative team proposes an 18 month, feasibility pilot study, randomizing 30 obese and diabetic individuals with UAN/COUAN to either phentermine/topiramate (n=20) or a pragmatic control group (n=10) who would remain on standard medication regimen (citrate salts, allopurinol, diet, etc).

Conditions

• Obesity
• Uric Acid Stones
• Type 2 Diabetes Mellitus in Obese
• Pre-Diabetes

Interventions

Type	Name	Description
DRUG	Phentermine / Topiramate Oral Product	All participants in the experimental group will receive oral generic tablet phentermine (18.75 or 37.5 mg dose) and topiramate (daily 100 mg or 150 mg dose)
COMBINATION_PRODUCT	Citrate Salts, Allopurinol, Diet	Control participants will complete initial visit requirements and study enrollment and will be maintained on their current therapy.

Timeline

• Start date: 2021-03-31
• Primary completion: 2024-11-14
• Completion: 2024-11-14
• First posted: 2020-11-09
• Last updated: 2026-01-30
• Results posted: 2026-01-30

Locations

1 site across 1 country: United States

Regulatory

• FDA-regulated drug study