18 and older, any sex, with Hyperkalemia or Chronic Kidney Disease. Patients with the condition only — healthy volunteers not accepted.
Results — posted to ClinicalTrials.gov
Per-arm endpoint measurements with 95% confidence intervals where reported. Source: trial results section.
Difference in the Exponential Rate of Change in Serum Potassium (S-K) Levels Versus Placebo During the Initial 48 Hours of Study Drug TreatmentPrimary· 24 and 48 hours post first study drug dose
The rate of fall in S-K levels during the initial 48 hours of study drug treatment between the placebo treated subjects and the ZS treated subjects measured on a log scale
Day2/0 Hr ( 24 hours)
Group
Value
95% CI
Placebo (Combined All Three Cohorts)
0
± NA
Sodium Zirconium Cyclosilicate (ZS) 0.3 g Three Times Daily
-0.00035
± 0.001166
Sodium Zirconium Cyclosilicate 3 g Three Times Daily
-0.00169
± 0.000932
Sodium Zirconium Cyclosilicate 10 g Three Times Daily
-0.000143
± 0.000932
Day 3/0 Hr (48 hours)
Group
Value
95% CI
Placebo (Combined All Three Cohorts)
0
± NA
Sodium Zirconium Cyclosilicate (ZS) 0.3 g Three Times Daily
-0.00045
± 0.000555
Sodium Zirconium Cyclosilicate 3 g Three Times Daily
-0.00089
± 0.000444
Sodium Zirconium Cyclosilicate 10 g Three Times Daily
-0.00256
± 0.000444
Serum Potassium (S-K) at Individual Time Points.Secondary· First 48 hours of study
Serum potassium (S-K) at individual time points through Study day 3/0hour.
Baseline
Group
Value
95% CI
Placebo (Combined All Three Cohorts)
5.14
± 0.358
Sodium Zirconium Cyclosilicate (ZS) 0.3 g Three Times Daily
5.22
± 0.264
Sodium Zirconium Cyclosilicate 3 g Three Times Daily
5.02
± 0.322
Sodium Zirconium Cyclosilicate 10 g Three Times Daily
5.05
± 0.359
Day 1/4Hr Post 1st Dose
Group
Value
95% CI
Placebo (Combined All Three Cohorts)
4.97
± 0.564
Sodium Zirconium Cyclosilicate (ZS) 0.3 g Three Times Daily
5.06
± 0.417
Sodium Zirconium Cyclosilicate 3 g Three Times Daily
4.93
± 0.518
Sodium Zirconium Cyclosilicate 10 g Three Times Daily
4.80
± 0.466
Day 1/4Hr Post 2nd Dose
Group
Value
95% CI
Placebo (Combined All Three Cohorts)
4.91
± 0.465
Sodium Zirconium Cyclosilicate (ZS) 0.3 g Three Times Daily
5.14
± 0.609
Sodium Zirconium Cyclosilicate 3 g Three Times Daily
4.80
± 0.543
Sodium Zirconium Cyclosilicate 10 g Three Times Daily
4.68
± 0.420
Day 1/4Hr Post 3rd Dose
Group
Value
95% CI
Placebo (Combined All Three Cohorts)
4.82
± 0.558
Sodium Zirconium Cyclosilicate (ZS) 0.3 g Three Times Daily
4.91
± 0.368
Sodium Zirconium Cyclosilicate 3 g Three Times Daily
4.68
± 0.577
Sodium Zirconium Cyclosilicate 10 g Three Times Daily
4.50
± 0.397
Day 2/0Hr
Group
Value
95% CI
Placebo (Combined All Three Cohorts)
4.97
± 0.521
Sodium Zirconium Cyclosilicate (ZS) 0.3 g Three Times Daily
4.90
± 0.447
Sodium Zirconium Cyclosilicate 3 g Three Times Daily
4.66
± 0.434
Sodium Zirconium Cyclosilicate 10 g Three Times Daily
4.73
± 0.463
Day 2/4Hr Post 1st Dose
Group
Value
95% CI
Placebo (Combined All Three Cohorts)
5.03
± 0.441
Sodium Zirconium Cyclosilicate (ZS) 0.3 g Three Times Daily
4.97
± 0.363
Sodium Zirconium Cyclosilicate 3 g Three Times Daily
4.81
± 0.601
Sodium Zirconium Cyclosilicate 10 g Three Times Daily
4.53
± 0.411
Day 2/4Hr Post 2nd Dose
Group
Value
95% CI
Placebo (Combined All Three Cohorts)
5.02
± 0.426
Sodium Zirconium Cyclosilicate (ZS) 0.3 g Three Times Daily
5.04
± 0.417
Sodium Zirconium Cyclosilicate 3 g Three Times Daily
4.72
± 0.604
Sodium Zirconium Cyclosilicate 10 g Three Times Daily
4.43
± 0.460
Day 2/4Hr Post 3rd Dose
Group
Value
95% CI
Placebo (Combined All Three Cohorts)
4.87
± 0.486
Sodium Zirconium Cyclosilicate (ZS) 0.3 g Three Times Daily
4.83
± 0.526
Sodium Zirconium Cyclosilicate 3 g Three Times Daily
4.60
± 0.566
Sodium Zirconium Cyclosilicate 10 g Three Times Daily
4.13
± 0.388
Time Specific S-K Levels to NormalizationSecondary· 48 and 72 hours post first study drug dose
Percent of subjects achieving S-K normalization (\<=as defined by S-K levels of 3.5 to 4.9 mmol/L) from baseline at Study Days 2 and 3 at 0 hr.
Day2/0Hr
Group
Value
95% CI
Placebo (Combined All Three Cohorts)
90
Sodium Zirconium Cyclosilicate (ZS) 0.3 g Three Times Daily
75
Sodium Zirconium Cyclosilicate 3 g Three Times Daily
95.8
Sodium Zirconium Cyclosilicate 10 g Three Times Daily
100
Day 3/0Hr
Group
Value
95% CI
Placebo (Combined All Three Cohorts)
90
Sodium Zirconium Cyclosilicate (ZS) 0.3 g Three Times Daily
100
Sodium Zirconium Cyclosilicate 3 g Three Times Daily
95.8
Sodium Zirconium Cyclosilicate 10 g Three Times Daily
100
Time Specific Decreases in S-K Levels of > = 0.5 mmol/LSecondary· 24 and 48 hours post first study drug dose
Percentage of participants achieving a 0.5mmol/L drop from baseline at Study Days 2 and 3 at 0 hr.
Day 2/0Hr
Group
Value
95% CI
Placebo (Combined All Three Cohorts)
16.7
Sodium Zirconium Cyclosilicate (ZS) 0.3 g Three Times Daily
33.3
Sodium Zirconium Cyclosilicate 3 g Three Times Daily
37.5
Sodium Zirconium Cyclosilicate 10 g Three Times Daily
33.3
Day 3/0Hr
Group
Value
95% CI
Placebo (Combined All Three Cohorts)
26.7
Sodium Zirconium Cyclosilicate (ZS) 0.3 g Three Times Daily
41.7
Sodium Zirconium Cyclosilicate 3 g Three Times Daily
41.7
Sodium Zirconium Cyclosilicate 10 g Three Times Daily
62.5
Percentage of Participants With Normal S-K Levels at End of Study Day 2Secondary· 48 hours post first study drug dose
Percentage (%) of subjects who achieve S-K normalization at end of Study Day 2
Group
Value
95% CI
Placebo (Combined All Three Cohorts)
90
Sodium Zirconium Cyclosilicate (ZS) 0.3 g Three Times Daily
75
Sodium Zirconium Cyclosilicate 3 g Three Times Daily
95.8
Sodium Zirconium Cyclosilicate 10 g Three Times Daily
100
Urine Sodium ExcretionSecondary· 24 and 48 hours post first study drug dose
Urine sodium excretion compared between the combined placebo-treated controls and the ZS-treated subjects (measured throughout two 24-hour periods on Study Days 1 and 2).
Baseline
Group
Value
95% CI
Placebo (Combined All Three Cohorts)
91.5
± 30.31
Sodium Zirconium Cyclosilicate (ZS) 0.3 g Three Times Daily
73.5
± 29.79
Sodium Zirconium Cyclosilicate 3 g Three Times Daily
81.7
± 33.16
Sodium Zirconium Cyclosilicate 10 g Three Times Daily
74.5
± 34.20
Day 1/0-24Hr
Group
Value
95% CI
Placebo (Combined All Three Cohorts)
74.4
± 24.8
Sodium Zirconium Cyclosilicate (ZS) 0.3 g Three Times Daily
66.7
± 18.49
Sodium Zirconium Cyclosilicate 3 g Three Times Daily
66.8
± 26.26
Sodium Zirconium Cyclosilicate 10 g Three Times Daily
67.1
± 29.19
Day 2/24-48Hr
Group
Value
95% CI
Placebo (Combined All Three Cohorts)
80.1
± 28.21
Sodium Zirconium Cyclosilicate (ZS) 0.3 g Three Times Daily
67.5
± 26.63
Sodium Zirconium Cyclosilicate 3 g Three Times Daily
71.6
± 31.61
Sodium Zirconium Cyclosilicate 10 g Three Times Daily
75.8
± 35.74
Urine Potassium ExcretionSecondary· 24 and 48 hours post study drug dose
Urine potassium excretion compared between the combined placebo-treated controls and the ZS-treated subjects (measured throughout two 24-hour periods on Study Days 1 and 2).
Baseline
Group
Value
95% CI
Placebo (Combined All Three Cohorts)
36.6
± 12.47
Sodium Zirconium Cyclosilicate (ZS) 0.3 g Three Times Daily
32.2
± 2.12
Sodium Zirconium Cyclosilicate 3 g Three Times Daily
38.3
± 11.82
Sodium Zirconium Cyclosilicate 10 g Three Times Daily
30.3
± 15.81
Day1/0-24Hr
Group
Value
95% CI
Placebo (Combined All Three Cohorts)
28.7
± 6.41
Sodium Zirconium Cyclosilicate (ZS) 0.3 g Three Times Daily
32.0
± 3.16
Sodium Zirconium Cyclosilicate 3 g Three Times Daily
30.6
± 5.96
Sodium Zirconium Cyclosilicate 10 g Three Times Daily
19.7
± 9.69
Day2/24-48Hr
Group
Value
95% CI
Placebo (Combined All Three Cohorts)
29.2
± 6.42
Sodium Zirconium Cyclosilicate (ZS) 0.3 g Three Times Daily
31.0
± 0.00
Sodium Zirconium Cyclosilicate 3 g Three Times Daily
30.5
± 6.51
Sodium Zirconium Cyclosilicate 10 g Three Times Daily
16.9
± 8.80
Urea Nitrogen ExcretionSecondary· 24 and 48 hours post study drug dose
Urea nitrogen excretion compared between the combined placebo-treated controls and the ZS-treated subjects (measured throughout two 24-hour periods on Study Days 1 and 2).
Baseline
Group
Value
95% CI
Placebo (Combined All Three Cohorts)
525.0
± 219.79
Sodium Zirconium Cyclosilicate (ZS) 0.3 g Three Times Daily
430.2
± 162.92
Sodium Zirconium Cyclosilicate 3 g Three Times Daily
481.0
± 198.92
Sodium Zirconium Cyclosilicate 10 g Three Times Daily
424.7
± 171.88
Day1/ 0-24 HR
Group
Value
95% CI
Placebo (Combined All Three Cohorts)
389.2
± 179.91
Sodium Zirconium Cyclosilicate (ZS) 0.3 g Three Times Daily
401.8
± 265.74
Sodium Zirconium Cyclosilicate 3 g Three Times Daily
414.1
± 177.54
Sodium Zirconium Cyclosilicate 10 g Three Times Daily
368.5
± 147.37
Day2/ 24-48 HR
Group
Value
95% CI
Placebo (Combined All Three Cohorts)
460.9
± 175.09
Sodium Zirconium Cyclosilicate (ZS) 0.3 g Three Times Daily
337.6
± 115.06
Sodium Zirconium Cyclosilicate 3 g Three Times Daily
477.0
± 157.04
Sodium Zirconium Cyclosilicate 10 g Three Times Daily
416.6
± 219.56
Blood Urea NitrogenSecondary· 24 and 48 hours post study drug dose
Blood urea nitrogen compared between the combined placebo-treated controls and the ZS-treated subjects (measured 24 \& 48 hours post dose on Study Days 2 and 3).
Baseline
Group
Value
95% CI
Placebo (Combined All Three Cohorts)
24.50
± 7.481
Sodium Zirconium Cyclosilicate (ZS) 0.3 g Three Times Daily
23.52
± 8.217
Sodium Zirconium Cyclosilicate 3 g Three Times Daily
25.16
± 8.065
Sodium Zirconium Cyclosilicate 10 g Three Times Daily
30.37
± 8.092
Day 2/)0Hr
Group
Value
95% CI
Placebo (Combined All Three Cohorts)
24.05
± 7.626
Sodium Zirconium Cyclosilicate (ZS) 0.3 g Three Times Daily
23.63
± 7.241
Sodium Zirconium Cyclosilicate 3 g Three Times Daily
23.98
± 7.619
Sodium Zirconium Cyclosilicate 10 g Three Times Daily
27.53
± 7.602
Day 3/0Hr
Group
Value
95% CI
Placebo (Combined All Three Cohorts)
24.50
± 7.284
Sodium Zirconium Cyclosilicate (ZS) 0.3 g Three Times Daily
23.33
± 7.895
Sodium Zirconium Cyclosilicate 3 g Three Times Daily
24.04
± 7.661
Sodium Zirconium Cyclosilicate 10 g Three Times Daily
25.60
± 7.942
Serum Magnesium (S-Mg) LevelsSecondary· 24 and 48 hours post study drug dose
Serum magnesium compared between the combined placebo-treated controls and the ZS-treated subjects (measured at 24 \& 48 hours post dose on Study Days 2 and 3).
Baseline
Group
Value
95% CI
Placebo (Combined All Three Cohorts)
1.93
± 0.258
Sodium Zirconium Cyclosilicate (ZS) 0.3 g Three Times Daily
1.95
± 0.327
Sodium Zirconium Cyclosilicate 3 g Three Times Daily
1.93
± 0.143
Sodium Zirconium Cyclosilicate 10 g Three Times Daily
1.85
± 0.235
Day 2/0Hr
Group
Value
95% CI
Placebo (Combined All Three Cohorts)
1.92
± 0.197
Sodium Zirconium Cyclosilicate (ZS) 0.3 g Three Times Daily
1.93
± 0.271
Sodium Zirconium Cyclosilicate 3 g Three Times Daily
1.94
± 0.182
Sodium Zirconium Cyclosilicate 10 g Three Times Daily
1.81
± 0.225
Day 3/0Hr
Group
Value
95% CI
Placebo (Combined All Three Cohorts)
1.90
± 0.204
Sodium Zirconium Cyclosilicate (ZS) 0.3 g Three Times Daily
1.89
± 0.257
Sodium Zirconium Cyclosilicate 3 g Three Times Daily
1.94
± 0.179
Sodium Zirconium Cyclosilicate 10 g Three Times Daily
1.83
± 0.218
Serum Calcium (S-Ca) LevelsSecondary· 24 and 48 hours post study drug dose
Serum calcium compared between the combined placebo-treated controls and the ZS-treated subjects (measured at 24 \& 48 hours post dose on Study Days 2 and 3).
Baseline
Group
Value
95% CI
Placebo (Combined All Three Cohorts)
9.46
± 0.595
Sodium Zirconium Cyclosilicate (ZS) 0.3 g Three Times Daily
9.37
± 0.341
Sodium Zirconium Cyclosilicate 3 g Three Times Daily
9.48
± 0.337
Sodium Zirconium Cyclosilicate 10 g Three Times Daily
9.50
± 0.469
Day 2/0 Hr
Group
Value
95% CI
Placebo (Combined All Three Cohorts)
9.39
± 0.439
Sodium Zirconium Cyclosilicate (ZS) 0.3 g Three Times Daily
9.36
± 0.507
Sodium Zirconium Cyclosilicate 3 g Three Times Daily
9.33
± 0.388
Sodium Zirconium Cyclosilicate 10 g Three Times Daily
9.22
± 0.466
Day 3/0 hr
Group
Value
95% CI
Placebo (Combined All Three Cohorts)
9.51
± 0.544
Sodium Zirconium Cyclosilicate (ZS) 0.3 g Three Times Daily
9.33
± 0.360
Sodium Zirconium Cyclosilicate 3 g Three Times Daily
9.30
± 0.397
Sodium Zirconium Cyclosilicate 10 g Three Times Daily
9.05
± 0.425
Serum Sodium (S-Na) LevelsSecondary· 24 and 48 hours post study drug dose
Serum sodium compared between the combined placebo-treated controls and the ZS-treated subjects (measured at 24 \& 48 hours post dose on Study Days 2 and 3).
Baseline
Group
Value
95% CI
Placebo (Combined All Three Cohorts)
139.4
± 2.84
Sodium Zirconium Cyclosilicate (ZS) 0.3 g Three Times Daily
139.1
± 3.65
Sodium Zirconium Cyclosilicate 3 g Three Times Daily
140.0
± 3.09
Sodium Zirconium Cyclosilicate 10 g Three Times Daily
137.7
± 3.45
Day 2/0 hr
Group
Value
95% CI
Placebo (Combined All Three Cohorts)
140.1
± 3.24
Sodium Zirconium Cyclosilicate (ZS) 0.3 g Three Times Daily
138.8
± 2.04
Sodium Zirconium Cyclosilicate 3 g Three Times Daily
140.1
± 3.83
Sodium Zirconium Cyclosilicate 10 g Three Times Daily
138.6
± 3.37
Day 3/0 hr
Group
Value
95% CI
Placebo (Combined All Three Cohorts)
140.0
± 3.36
Sodium Zirconium Cyclosilicate (ZS) 0.3 g Three Times Daily
138.5
± 2.28
Sodium Zirconium Cyclosilicate 3 g Three Times Daily
140.0
± 3.91
Sodium Zirconium Cyclosilicate 10 g Three Times Daily
139.6
± 3.50
Adverse events — posted to ClinicalTrials.gov
Time frame: Study Days 1 to 7.
Reporting threshold: 3%.
Adverse-event reports describe events observed during the trial — not all are caused by the drug.
Placebo
Serious: 0/30 (0%)
Deaths: 0/30
Sodium Zirconium Cyclosilicate (ZS) 0.3 g Three Times Daily
Serious: 0/12 (0%)
Deaths: 0/12
Sodium Zirconium Cyclosilicate 3 g Three Times Daily
Serious: 0/24 (0%)
Deaths: 0/24
Sodium Zirconium Cyclosilicate 10 g Three Times Daily
It is hypothesized that zirconium silicate is safe and well tolerated and more effective than placebo (alternative hypothesis) in lowering serum potassium levels in subjects with serum potassium between 5 - 6.0 mmol/l versus no difference between zirconium silicate and placebo (null hypothesis). It is hypothesized that zirconium silicate even up to the top dose of 10g three times a day is well tolerated.
Publications & conference data
4 peer-reviewed publications reference this trial (live from Europe PMC):
Publications: Europe PMC API search by NCT ID, retrieved 10 June 2026
Drug + disease cross-links: matched in real time against Drug Landscape's normalised drug + company + condition tables
Sponsor: as reported to ClinicalTrials.gov by ZS Pharma, Inc.
Last refreshed: 29 June 2018
Drug Landscape aggregates and links these public records for informational use only. Always verify against the primary source before clinical or regulatory decisions. Canonical URL: https://druglandscape.com/trial/NCT01493024.