['hyperkalemia']
['sodium zirconium cyclosilicate']

        Inclusion Criteria:

          -  Provision of written informed consent.

          -  Over 18 years of age.

          -  Two consecutive i STAT potassium values, measured 60 (+/- 15) minutes apart, both >/=
             5.1 mmol/L and measured within 1 day before the first dose of ZS on Acute Phase Study
             Day 1.

          -  Ability to have repeated blood draws or effective venous catheterization.

          -  Women of childbearing potential must be using 2 forms of medically acceptable
             contraception (at least 1 barrier method) and have a negative pregnancy test at Acute
             Phase Study Day 1. Women who are surgically sterile or those who are postmenopausal
             for at least 2 years are not considered to be of childbearing potential.

          -  Controlled diabetic subjects.

        Exclusion Criteria:

          -  Pseudohyperkalemia signs and symptoms, such as hemolyzed blood specimen due to
             excessive fist clenching to make veins prominent, difficult or traumatic venipuncture,
             or history of severe leukocytosis or thrombocytosis.

          -  Subjects treated with lactulose, rifaximin, or other non-absorbed antibiotics for
             hyperammonemia within 7 days prior to first dose of ZS on Acute Phase Study Day 1.

          -  Subjects treated with sodium polystyrene sulfonate (SPS; eg, Kayexalate®) or calcium
             polystyrene sulfonate (eg, Resonium®) within 3 days prior to first dose of ZS on Acute
             Phase Study Day 1.

          -  Subjects with a life expectancy of less than 12 months.

          -  Subjects who are severely physically or mentally incapacitated and who, in the opinion
             of investigator, are unable to perform the subjects' tasks associated with the
             protocol.

          -  Women who are pregnant, lactating, or planning to become pregnant.

          -  Subjects with diabetic ketoacidosis.

          -  Presence of any condition which, in the opinion of the investigator, places the
             subject at undue risk or potentially jeopardizes the quality of the data to be
             generated.

          -  Known hypersensitivity or previous anaphylaxis to ZS or to components thereof.

          -  Treatment with a drug or device within the last 30 days that has not received
             regulatory approval at the time of study entry.

          -  Subjects with cardiac arrhythmias that require immediate treatment.

          -  Subjects on dialysis.

          -  Subjects randomized into the previous ZS-002, ZS-003, ZS-004, or ZS-004E studies.

          -  Documented GFR <15 mL/min within 90 days prior to study entry.
      