Abstract: SA-PO163

Pyridoxine Lowers Urine Oxalate in Kidney Stone Formers with Enteric Hyperoxaluria

Session Information

Category: Nutrition, Inflammation, and Metabolism

  • 1401 Nutrition, Inflammation, Metabolism


  • Scott, Jennifer, Mayo Clinic, Phoenix, Arizona, United States
  • Humphreys, Mitchell, Mayo Clinic, Phoenix, Arizona, United States
  • Mcadams, Sean, Mayo Clinic, Phoenix, Arizona, United States
  • Keddis, Mira T., Mayo Clinic, Phoenix, Arizona, United States

Pyridoxine is commonly deficient in patients with enteric hyperoxaluria. We hypothesize that pyridoxine replacement may reduce urine oxalate in stone formers with enteric hyperoxaluria.


All patients with nephrolithiasis and urine metabolic analysis between 2008-2016 at Mayo Clinic Arizona were identified. Patients with 24-hour urine oxalate >40 mg and prescribed pyridoxine were included in the study (n=13). Patients with primary hyperoxaluria were excluded.


13 patients with risk factors for enteric hyperoxaluria were prescribed pyridoxine for treatment of nephrolithiasis. 10 (77%) patients had urine metabolic studies performed post-treatment. 5 were male, with mean age of 57.7± 10.7 years. 5 had <2 L/24hr of urine volume, 3 had hypocitraturia (<440mg/24hr), and 3 had hypercalcuria (>200mg/24hr). The mean baseline 24-hour urine oxalate was 70.67 ± 39.40 mg/d. Pyridoxine dose ranged from 25-100mg/d. Repeat urine was performed after median of 10 months (1.5-21). Mean 24-hour urine oxalate was 57.86 ± 33.09 mg/d after treatment (mean difference 12.8 ± 29 mg/d). Urine oxalate level improved in 7 and normalized in 4 patients post-treatment. There was no statistically significant difference between urine oxalate levels pre- and post- pyridoxine treatment (p 0.31). 7 patients had stone analysis performed, 6 of whom had predominately calcium oxalate stones. Only 3 of 10 patients treated had recurrent kidney stones after pyridoxine treatment.


In our cohort, pyridoxine improved hyperoxaluria and decreased risk of recurrent nephrolithiasis in 70% of patients. Future studies are required to evaluate the dose of pyridoxine and validate our findings in a larger cohort of patients with malabsorptive enteric hyperoxaluria.

PatientPyridoxine dose(mg)Urine volume(L)Oxalate(mg)Citrate(mg)Calcium(mg)Urine volume(L)Oxalate(mg)Citrate(mg)Calcium(mg)
  24hr baseline   24hr post-treatment   
3 2.5144.3855.6196.81.1726.5167.5134.5
6 3.49173.652.3110.32.96111.144.561.6