Effect of Patiromer on Urinary Ion Excretion in Healthy Adults.
Patiromer is a nonabsorbed potassium-binding polymer that uses calcium as the counterexchange ion. The calcium released with potassium binding has the potential to be absorbed or bind phosphate. Because binding is not specific for potassium, patiromer can bind other cations. Here, we evaluate the effect of patiromer on urine ion excretion in healthy adults, which reflects gastrointestinal ion absorption.



We analyzed the effect of patiromer on urine potassium, sodium, magnesium, calcium, and phosphate in two studies. Healthy adults on controlled diets in a clinical research unit were given patiromer up to 50.4 g/d divided three times a day for 8 days (dose-finding study) or 25.2 g/d in a crossover design as daily or divided (two or three times a day) doses for 18 days (dosing regimen study). On the basis of 24-hour collections, urinary ion excretion during the baseline period (days 5-11) was compared with that during the treatment period (days 13-19; dose-finding study), and the last 4 days of each period were compared across regimens (dosing regimen study).



In the dose-finding study, patiromer induced a dose-dependent decrease in urine potassium, urine magnesium, and urine sodium (P<0.01 for each). Patiromer at 25.2 g/d decreased urine potassium (mean±SD) by 1140±316 mg/d, urine magnesium by 45±1 mg/d, and urine sodium by 225±145 mg/d. Urine calcium increased in a dose-dependent manner, and urine phosphate decreased in parallel (bothP<0.01). Patiromer at 25.2 g/d increased urine calcium by 73±23 mg/d and decreased urine phosphate by 64±40 mg/d. Urine potassium, urine sodium, and urine magnesium were unaffected by dosing regimen, whereas the increase in urine calcium was significantly lower with daily compared with three times a day dosing (P=0.01). Urine phosphate also decreased less with daily compared with two or three times a day dosing (P<0.05).



In healthy adults, patiromer reduces urine potassium, urine sodium, urine magnesium, and urine phosphate, while modestly increasing urine calcium. Compared with divided dosing, administration of patiromer once daily provides equivalent reductions in urine potassium, urine sodium, and urine magnesium, with less effect on urine calcium and urine phosphate.
Division of Nephrology, Department of Medicine, University of Rochester, Rochester, New York.
David A
DA
Bushinsky
Relypsa, Redwood City, California.
David M
DM
Spiegel
Relypsa, Redwood City, California.
Coleman
C
Gross
Relypsa, Redwood City, California.
Wade W
WW
Benton
Relypsa, Redwood City, California.
Jeanene
J
Fogli
Department of Nutrition Science, Purdue University, West Lafayette, Indiana.
Kathleen M
KM
Hill Gallant
Relypsa, Redwood City, California.
Charles
C
Du Mond
Clinical Research at Colorado Kidney Care, Denver, Colorado.
Geoffrey A
GA
Block
Division of Nephrology, Department of Medicine, University of Maryland, Baltimore, Maryland; and.
Matthew R
MR
Weir
Division of Cardiology, University of Michigan School of Medicine, Ann Arbor, Michigan.
Bertram
B
Pitt
D000293:Adolescent; D000328:Adult; D002118:Calcium / Q000652:urine; D018592:Cross-Over Studies; D004032:Diet; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D065569:Gastrointestinal Absorption / Q000187:drug effects*; D064368:Healthy Volunteers; D006801:Humans; D007477:Ions; D008274:Magnesium / Q000652:urine; D008297:Male; D008875:Middle Aged; D010710:Phosphates / Q000652:urine; D011108:Polymers / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology*; D011188:Potassium / Q000652:urine; D012964:Sodium / Q000652:urine; D016482:Urinalysis; D055815:Young Adult
D007477:Ions; D010710:Phosphates; D011108:Polymers; C568789:patiromer; D012964:Sodium; D008274:Magnesium; D011188:Potassium; D002118:Calcium
Animals; Brachyura; Calcium, Dietary; Cations; Cross-Over Studies; Diet; Gastrointestinal Absorption; Intestinal Absorption; Magnesium; Phosphates; Polymers; Potassium; Sodium; calcium; cation exchange; electrolytes; hyperkalemia; patiromer; urinary excretion
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