Sustained reduction in urinary calcium during long-term treatment with slow release neutral potassium phosphate in absorptive hypercalciuria.
OBJECTIVE
We tested whether UroPhos-K, a new slow release neutral form of potassium phosphate (155 mg. phosphate, 8 mEq. potassium per tablet) in a dose of 4 tablets twice daily would produce a sustained hypocalciuric response and maintain bone mass in patients with absorptive hypercalciuria, a major cause of nephrolithiasis characterized by excessive intestinal calcium absorption accompanied in some patients by excessive bone loss.


METHODS
A total of 25 patients with absorptive hypercalciuria were studied in a 4-year, prospective, open trial with UroPhos-K at yearly intervals during a 4-day inpatient physiological study with a constant metabolic diet containing 400 mg. calcium, 100 mEq. sodium and 800 mg. phosphate daily.


RESULTS
Treatment with UroPhos-K caused a sustained, marked reduction in urinary calcium (264 to 181 mg. daily). Fractional 47calcium absorption decreased modestly (74.0 to 64.6%) commensurate with a reduction in serum 1,25-dihydroxyvitamin D (42 to 34 pg./ml.). Intact parathyroid hormone increased within the normal range (30 to 42 pg./ml.). Bone mineral density was stable at the lumbar spine, femoral neck and distal third of the radius.


CONCLUSIONS
UroPhos-K may provide a long-term alternative for hypercalciuric patients in whom thiazide therapy fails.
Heller
H J
HJ
Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas 75235-8885, USA.
Reza-Albarrán
A A
AA
Breslau
N A
NA
Pak
C Y
CY
D000328:Adult; D000368:Aged; D015519:Bone Density; D002021:Buffers; D002118:Calcium / Q000652:urine*; D002128:Calcium Metabolism Disorders / Q000188:drug therapy; D003692:Delayed-Action Preparations; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010710:Phosphates / Q000008:administration & dosage / Q000627:therapeutic use*; D017680:Potassium Compounds / Q000008:administration & dosage / Q000627:therapeutic use*; D011446:Prospective Studies
D002021:Buffers; D003692:Delayed-Action Preparations; D010710:Phosphates; D017680:Potassium Compounds; C013216:potassium phosphate; D002118:Calcium