One main study involving adults with chronic kidney disease who had hyperkalaemia found that Veltassa is effective in reducing potassium levels in the blood.

In the first part of the study, 243 patients with hyperkalaemia (with an average potassium level of 5.6 mmol/litre) were treated with Veltassa. After 4 weeks of treatment, their potassium level fell on average by 1.0 mmol/litre.

The second part of the study compared Veltassa with placebo (a dummy treatment) in 107 patients whose potassium level had fallen with Veltassa during the first part of the study. After 4 weeks, the average potassium level did not change in patients who received Veltassa but it went back up by an average of 0.7 mmol/litre in patients who received placebo.

Another study involved 14 adolescents aged 12 years and above with hyperkalaemia (with an average potassium level of 5.5 mmol/litre). After 14 days of treatment with Veltassa, their potassium levels fell on average by 0.5 mmol/litre. This effect persisted, leading to an average reduction by 1.1 mmol/litre after 26 weeks of treatment.