Use of sevelamer hydrochloride as an oxalate binder.
OBJECTIVE
We tested the hypothesis that the cationic phosphate binder sevelamer hydrochloride could reduce hyperoxaluria and calcium oxalate supersaturation in patients with enteric hyperoxaluria by binding fatty acids, binding phosphate and rendering calcium free to bind oxalate, and/or directly binding oxalate. A secondary objective was to assess changes in the urinary excretion of other substances associated with nephrolithiasis.


METHODS
Ten patients with enteric hyperoxaluria were enrolled in a nonrandomized, open label trial of sevelamer hydrochloride (3,200 mg 3 times daily for 7 days).


RESULTS
With treatment mean urinary oxalate decreased 17% (0.84 to 0.70 mmol per day) and the urinary oxalate-to-creatinine ratio decreased 11% (0.055 to 0.049 mmol/mmol, p not significant for both). Urinary calcium increased 25% (p not significant). Urinary citrate decreased 23% (p = 0.01) and urinary phosphorus decreased 44% (p = 0.0001). Mean supersaturation of calcium oxalate, brushite, hydroxyapatite, uric acid and sodium urate did not change significantly. However, the decrease in brushite supersaturation approached statistical significance (p = 0.07). Mean serum phosphorus was 3.6 mg/dl at baseline and 3.3 mg/dl with therapy (p not significant). Hypophosphatemia did not develop in any patients. One patient dropped out of study due to abdominal pain.


CONCLUSIONS
Sevelamer hydrochloride dramatically decreased urinary phosphorus excretion with a lesser effect on urinary oxalate. Supersaturation of calcium oxalate did not decrease due to countervailing effects on other constituents including an increase in urinary calcium and a decrease in urinary citrate. Although sevelamer hydrochloride may not be an ideal agent for correcting hyperoxaluria, its potential to reduce calcium phosphate supersaturation merits further investigation.
Lieske
John C
JC
Mayo Clinic Division of Nephrology and Hypertension and Mayo Hyperoxaluria Center, Rochester, Minnesota 55905, USA. Lieske.John@mayo.edu
Regnier
Cynthia
C
Dillon
John J
JJ
D000328:Adult; D002129:Calcium Oxalate / Q000378:metabolism*; D002614:Chelating Agents / Q000494:pharmacology / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D006959:Hyperoxaluria / Q000188:drug therapy* / Q000209:etiology; D008297:Male; D008875:Middle Aged; D053040:Nephrolithiasis / Q000378:metabolism; D010070:Oxalates / Q000652:urine; D010758:Phosphorus / Q000652:urine; D010865:Pilot Projects; D011073:Polyamines / Q000494:pharmacology / Q000627:therapeutic use*; D000069603:Sevelamer
D002614:Chelating Agents; D010070:Oxalates; D011073:Polyamines; D002129:Calcium Oxalate; D010758:Phosphorus; D000069603:Sevelamer