Patiromer in the management of hyperkalaemia

Patiromer acetate is a nonabsorbable cation exchange polymer that has been approved for management of hyperkalaemia

Patiromer acetate

• decreases serum potassium by exchanging calcium for potassium in the intestine, especially the colon, resulting in gastrointestinal loss of potassium
  • potassium is the most abundant cation in the colon, and patiromer remains for the longest period in this segment of the gastrointestinal tract
  • patiromer binds potassium, and to a lesser extent, hydrogen and other cations, while releasing calcium
  • most of the absorbed calcium load from patiromer is excreted into the urine
    • may raise the risk of calcium-containing kidney stones
• considered safe and well tolerated
  • gastrointestinal side effects include diarrhea, constipation, flatulence, and vomiting. Other potential side effects include hypomagnesemia and hypokalemia
  • hypercalcaemia has been reported as a potential adverse effect (1)
    • with a reduced GFR, the increment in urinary calcium excretion associated with use of patiromer is reduced and the theoretical possibilities of hypercalcemia and ectopic calcifications have been raised (2)

NICE suggest that (3):

• patiromer is recommended as an option for treating hyperkalaemia in adults only if used:
  • in emergency care for acute life-threatening hyperkalaemia alongside standard care or
  • for people with persistent hyperkalaemia and stages 3b to 5 chronic kidney disease or heart failure, if they:
    • have a confirmed serum potassium level of at least 6.0 mmol/litre and
    • are not taking, or are taking a reduced dosage of, a renin-angiotensin-aldosterone system (RAAS) inhibitor because of hyperkalaemia and
    • are not on dialysis
• stop patiromer if RAAS inhibitors are no longer suitable

It was noted onset of action for patiromer is 4 to 7 hours and patiromer should not replace emergency treatment for life-threatening hyperkalaemia. The NICE committee noted that patiromer could have a role in treating life-threatening hyperkalaemia alongside usual care

• it would not replace intravenous insulin and glucose, but it might replace calcium resonium (3)

In a study to investigate the impact of patiromer on serum potassium level and its ability to enable specified target doses of renin-angiotensin-aldosterone system inhibitor (RAASi) use in patients with heart failure and reduced ejection fraction (HFrEF) it was found that concurrent use of patiromer and high-dose mineralocorticoid receptor antagonist (50mg spironolactone/eplerenone) reduced risk of recurrent hyperkalaemia vs placebo (at median 27 weeks, mean change potassium +0.03 mmol/L vs +0.13 mmol/L; respectively; p<0.001) (4)

The respective Summary of Product Characteristics should be consulted before prescribing this drug.

Reference:

(1) BhattaraiS et al. Patiromer Acetate Induced Hypercalcemia: An Unreported Adverse Effect. Case Rep Nephrol. 2019; 2019: 3507407

(2) Sterns RH, Grieff M, Bernstein PL. Treatment of hyperkalemia: something old, something new. Kidney Int. 2016 Mar;89(3):546-54. doi: 10.1016/j.kint.2015.11.018.

(3) NICE (February 2020). Patiromer for treating hyperkalaemia
(4) Butler J et al. Patiromer for the management of hyperkalemia in heart failure with reduced ejection fraction: the DIAMOND trial, European Heart Journal, 2022;, ehac401,