Table 2 Comparison of potassium exchange resins for the treatment of hyperkalemia

Trade name

Kayexalate®, Kionex®

Veltessa®

Lokelma®

FDA approval

1958 (prior to drug regulation laws)

2015

2018

Onset of action

2–24 h

2 h

1 h

Mode of action

The sulfonate molecule exists as sulfonic acid in its ionic state and allows for interaction with a Na⁺ counterion. In this method, Na⁺ is exchanged for K⁺ within the gastrointestinal tract

Utilizes the high colonic K⁺ concentration and exchanges its Ca²⁺ counterion for it. The attached fluorine atom at the alpha-carbon position of patiromer causes electron-withdrawing effects and generates a lower pKa compared to colonic pH. This allows the resin to exist in an ionized state and bind K⁺ effectively

Selectively binds to K⁺ throughout the length of the gastrointestinal tract. SZC mimics physiological K⁺ ion channels by utilizing a thermodynamically favorable binding pocket unique to the size of K⁺

Degree of K⁺ lowering

1.04 mEq/L^a

0.6 mEq/L^b

0.4 mEq/L^c

Location of efficacy

Large intestine

Distal colon

Small intestine and large intestine

Toxicity

Na⁺ loading/fluid overload, hypomagnesemia, hypocalcemia, colonic necrosis

Hypomagnesemia

Edema

Side effects

Nausea, vomiting, diarrhea, constipation, abdominal pain

Mild-severe constipation, abdominal pain

Constipation, abdominal pain

Exchange ion

Na⁺

Ca²⁺

H⁺, Na⁺

Selectivity

Non-specific, K⁺, Ca²⁺, Mg²⁺

Specific, K⁺ (low specificity, Mg²⁺)

Highly specific, K⁺ and ammonium

Resin size

 ~ 11–124 µm

 ~ 100 µm

 > 3 µm (non-absorbed)

Molecular composition

Polymer resin consisting of sulfonate and attached vinylbenzene (styrene) R group

Polymer resin with attached carboxylic acid and fluorine atom at alpha carbon position

Three-dimensional, seven-member ring lattice made up of alternating zirconium and silicate atoms with adjoining oxygen atoms