Table 1.

Pharmacologic comparison of potassium-lowering agents

Pharmacologic property	Sodium polystyrene sulfonate (SPS)11	Patiromer calcium sorbitex20–22	Sodium zirconium cyclosilicate18,23–25
Brand name	Kayexalate	Veltassa	None (not FDA-approved)
Mechanism of action	Binds potassium in the gastrointestinal tract and facilitates excretion in the feces	Binds potassium in the gastrointestinal tract and facilitates excretion in the feces	Binds potassium in the gastrointestinal tract and facilitates excretion in the feces
Selectivity for potassium ion	Nonselective; also binds calcium and magnesium	Selective; also binds magnesium	Highly selective; nine times the potassium-binding capacity compared to SPS; also binds ammonium
Sodium content	1,500 mg sodium per 15 g dose	No sodium content	Approximately 1,000 mg sodium per 10 g dose
Sorbitol content	20 g sorbitol per 15 g dose	4 g sorbitol per 8.4 g dose	No sorbitol content
Onset of effect	Variable; 2–6 hours	7–48 hours	1–6 hours
Duration of effect	Variable; 6–24 hours	12–24 hours	Unclear; appears to be 4–12 hours based on trial data
Dosing	15 g PO one to four times per day	8.4 g PO once daily with a meal; titrated to 25.2 g/day based on response	10 g PO three times daily with meals for acute treatment; 5, 10, or 15 g PO once daily with breakfast for chronic treatment (not approved; based on trial data)
Preparation(s)/administration	Liquid or powder for suspension; mix with water (3–4 mL per g of drug) and administer within 24 hours	Powder for suspension; mix with water (90 mL) and administer immediately; store in refrigerator (36–46°F or 2–8°C); use within 3 months upon removal from refrigerator	White, tasteless powder for suspension; mix vigorously with water (240 mL) and administer immediately

Abbreviations: FDA, US Food and Drug Administration; PO, per os (by mouth); SPS, sodium polystyrene sulfonate.