To investigate the efficacy of each ZG-801 starting dose and the titration algorithm of ZG-801 for the treatment of hyperkalemia in Japanese patients.

To evaluate the safety of ZG-801 for the chronic use (total over 52 weeks). In addition, to confirm the safety after the discontinuation of ZG-801 treatment on 1 week follow-up.

Inclusion Criteria:

• Males and females ages 18 - 80
• Informed consent given
• Serum Potassium measurement at baseline is 5.1 to < 6.5 mEq/L (Non-dialysis patients or 5.5 to < 6.5 mEq/L (Dialysis patients)

Exclusion Criteria:

• Subjects with hospitalization for hyper- or hypoglycemia with Type 2 diabetes or for acute exacerbations of heart failure within the previous 3 months
• Subjects with severe heart failure, defined as NYHA (New York Heart Association) class IV
• Subjects with uncorrected hemodynamically significant primary vascular disease or uncontrolled or hemodynamically unstable arrhythmia
• Subjects with coronary artery bypass graft, percutaneous intervention, or major surgery including thoracic and cardiac, within the previous 3 months or anticipated need during study participation
• Subjects with heart, liver (only Dialysis patients), or kidney transplant recipient, or anticipated need for transplant during the study period
• Subjects with any of the significant cardiovascular or cerebrovascular events within the previous 2 months
• Subjects with a history of or current diagnosis of a severe swallowing disorder, moderate to severe gastroparesis, or history of bariatric surgery, bowel obstruction or severe gastrointestinal disorders or major gastrointestinal surgery
• Subjects who cannot use the oral concomitant medication to be separate 3 hours from ZG-801 medication
• Subjects suspected of transient high potassium levels, such as those caused only by dietary effects