Physiological effects of slow release potassium phosphate for absorptive hypercalciuria: a randomized double-blind trial.
OBJECTIVE
We examined the physiological effects and tolerance of UroPhos-K, a slow release neutral form of potassium phosphate (155 mg. phosphate and 8 mEq. potassium per tablet) in patients with absorptive hypercalciuria.


METHODS
A total of 31 patients with absorptive hypercalciuria were studied at baseline and after 3 months of treatment with 4 tablets twice daily of UroPhos-K or placebo (identical in appearance) in a prospective randomized, placebo controlled, double-blind trial during a 4-day inpatient study with a daily constant metabolic diet containing 400 mg. calcium, 100 mEq. sodium and 800 mg. phosphate.


RESULTS
Treatment with UroPhos-K did not cause significant gastrointestinal side effects, increase fasting serum potassium or phosphorus, or reduce hemoglobin or creatinine clearance. It reduced urinary calcium excretion from 277 +/- 72 to 166 +/- 43 mg. per day (p < 0.001), associated with a reduction in serum 1,25-dihydroxyvitamin D concentration from 50 +/- 11 to 42 +/- 9 pg./ml. (p < 0.001). Indexes of intestinal calcium absorption and markers of bone turnover also decreased modestly. None of these changes was seen in the placebo group.


CONCLUSIONS
In patients with absorptive hypercalciuria UroPhos-K seems to correct hypercalciuria by a combination of reduced intestinal absorption, bone resorption and improved renal calcium reabsorption. The drug is well tolerated compared to placebo.
Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, USA.
N A
NA
Breslau
H J
HJ
Heller
A A
AA
Reza-Albarrán
C Y
CY
Pak
D000328:Adult; D000368:Aged; D002118:Calcium / Q000652:urine*; D003692:Delayed-Action Preparations; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008659:Metabolic Diseases / Q000188:drug therapy*; D008875:Middle Aged; D010710:Phosphates / Q000627:therapeutic use*; D017680:Potassium Compounds / Q000627:therapeutic use*
D003692:Delayed-Action Preparations; D010710:Phosphates; D017680:Potassium Compounds; C013216:potassium phosphate; D002118:Calcium