What is the dose of Kayexalate (sodium polystyrene sulfonate) for hyperkalemia?

Kayexalate Dosing for Hyperkalemia

The recommended dose of Kayexalate (sodium polystyrene sulfonate) for hyperkalemia is 15-50 g plus sorbitol per oral or per rectum. 1

Adult Dosing

• Oral administration: 15 g (60 mL) to 60 g (240 mL) of suspension daily, typically given as 15 g (60 mL) one to four times daily 2
• Rectal administration: 30 g (120 mL) to 50 g (200 mL) every six hours 2

Pediatric Dosing

• Oral: 1 g/kg up to 15 g (60 mL) every 6 hours as needed 1
• Rectal: 1 g/kg up to 50 g every 6 hours as needed 1

Administration Guidelines

Oral Administration

• Administer at least 3 hours before or 3 hours after other oral medications
• Patients with gastroparesis may require a 6-hour separation 2
• Administer with patient in upright position
• May be introduced through a nasogastric tube if necessary

Rectal Administration

• After initial cleansing enema, insert a large size (French 28) rubber tube into the rectum for about 20 cm
• Introduce suspension at body temperature by gravity
• Flush with 50-100 mL of fluid
• Keep in sigmoid colon for several hours if possible
• Follow with sodium-free cleansing enema 2

Important Warnings and Precautions

1. Risk of GI necrosis: Kayexalate, especially when combined with sorbitol, has been associated with intestinal necrosis, which can be fatal 3, 4

2. Electrolyte disturbances:

   • Contains 1500 mg (65 mEq) of sodium per 60 mL dose 2
   • Can cause hypomagnesemia, hypokalemia, hypocalcemia, and systemic alkalosis 1

3. Special populations:

   • Neonates: Avoid using commercially available liquid preparation in neonates due to hyperosmolar preservative (sorbitol) content. Hospital pharmacies can prepare sorbitol-free preparations 1
   • Extremely preterm neonates: May develop intestinal hemorrhage (hematochezia) from rectal Kayexalate 1

4. Efficacy considerations:

   • In-vivo efficiency of sodium-potassium exchange is approximately 33% 2
   • May be less effective than other treatments for hyperkalemia in certain populations 5

Alternative Treatments for Hyperkalemia

For severe hyperkalemia, consider a stepwise approach:

1. Stabilize myocardial cell membrane:

   • Calcium chloride (10%): 5-10 mL IV over 2-5 minutes, or
   • Calcium gluconate (10%): 15-30 mL IV over 2-5 minutes

2. Shift potassium into cells:

   • Sodium bicarbonate: 50 mEq IV over 5 minutes
   • Glucose plus insulin: 25 g glucose and 10 U regular insulin IV over 15-30 minutes
   • Nebulized albuterol: 10-20 mg over 15 minutes

3. Promote potassium excretion:

   • Diuresis: furosemide 40-80 mg IV
   • Kayexalate: 15-50 g plus sorbitol PO or PR
   • Dialysis (for severe cases) 1

Efficacy Evidence

A randomized clinical trial demonstrated that sodium polystyrene sulfonate (30 g daily for 7 days) was superior to placebo in reducing serum potassium levels in patients with mild hyperkalemia and CKD (mean difference between groups: -1.04 mEq/L) 6.

However, newer potassium binders may offer advantages over Kayexalate, including faster onset of action, better selectivity for potassium, and potentially improved safety profiles 1.