Patiromer induces an early and sustained lowering of potassium levels in hyperkalemic patients with chronic kidney disease (CKD) who were on renin-angiotensin-aldosterone system (RAAS) inhibitor therapy, according to a new study.

After a single dose of the nonabsorbed potassium binder, researchers observed a significant decrease in mean serum potassium by 7 hours.

In addition, results showed that that the drug was well tolerated, with no patient experiencing serious adverse events or withdrawing from the study.

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David A. Bushinsky, MD, of the University of Rochester Medical Center in Rochester, N.Y., and colleagues enrolled 27 hyperkalemic CKD patients taking at least one renin-angiotensin-aldosterone system (RAAS) inhibitor. Of the 27 patients, 25 had sustained hyperkalemia (serum potassium level above 5.5 but less than 6.5 mEq/L) following a 3-day day potassium- and sodium-restricted diet in an inpatient research unit.

Previous studies of patiromer have focused on the drug’s safety, efficacy, and tolerability in the treatment of hyperkalemic patients in studies that have ranged from 12 to 52 weeks. The earliest time point at which the drug’s effect on potassium was measured routinely in those studies was 48 hours after the initial dose. The impact of patiromer on serum potassium levels prior to 48 hours was unknown. The purpose of the study by Dr. Bushinsky’s group was to characterize the onset of action of patiromer’s potassium-lowering activity in the interval between the initial dose and 48 hours post-dose.

In the new study, patients received patiromer 8.4 grams per dose with morning and evening meals for a total of 4 doses. The investigators measured serum potassium at baseline, 4 hours, and then every 2–4 hours up to 48 hours, 58, hours, and during outpatient follow-up.

Patients had mean serum potassium level of 5.93 mEq/L at baseline. This was reduced significantly by 0.21 mEq/L by 7 hours after the first dose. Significant decreases occurred at all time points from 7 to 48 hours. A mean serum potassium level of 5.41 mEq/L was achieved by 20 hours, the investigators reported online ahead of print in Kidney International. At 48 hours (14 hours after the final dose), the researchers observed a significant mean reduction of 0.75 mEq/L. Serum potassium levels did not increase before the next dose or for 24 hours after the last dose, according to the investigators.