Kayexalate Dosage for Hyperkalemia
The recommended dosage of Kayexalate (sodium polystyrene sulfonate) for treating hyperkalemia is 15-60 g orally per day, administered as 15 g one to four times daily, or 30-50 g rectally every six hours. 1
Oral Administration
- The average total daily adult dose is 15-60 g, typically given as 15 g (four level teaspoons) one to four times daily 1
- Each dose should be suspended in a small quantity of water or syrup (approximately 3-4 mL of liquid per gram of resin) 1
- Prepare the suspension fresh and use within 24 hours; do not heat as it could alter the exchange properties of the resin 1
- One level teaspoon contains approximately 3.5 g of sodium polystyrene sulfonate and 15 mEq of sodium 1
Rectal Administration
- The average adult rectal dose is 30-50 g every six hours 1
- For rectal administration, after an initial cleansing enema, insert a soft large rubber tube (French 28) into the rectum for about 20 cm with the tip well into the sigmoid colon 1
- Administer as a warm emulsion in 100 mL of aqueous vehicle and flush with 50-100 mL of fluid 1
- The resin should be retained for as long as possible, followed by a cleansing enema with a non-sodium containing solution 1
Important Considerations
- Kayexalate should NOT be used as emergency treatment for life-threatening hyperkalemia due to its delayed onset of action (several hours to days) 2, 1
- For acute, severe hyperkalemia, more rapid-acting treatments should be used first (calcium, insulin/glucose, nebulized albuterol) 3, 2
- Administer Kayexalate at least 3 hours before or 3 hours after other oral medications (patients with gastroparesis may require a 6-hour separation) 1
- Regular monitoring of serum potassium is essential during therapy; also monitor calcium and magnesium levels as Kayexalate is not totally selective for potassium and can bind other cations 2, 1
Safety Concerns
- Serious gastrointestinal adverse events including intestinal necrosis (sometimes fatal), bleeding, ischemic colitis, and perforation have been reported 1, 4
- Avoid use in patients with obstructive bowel disease, abnormal bowel function, or those at risk for developing constipation or impaction 1
- Discontinue use in patients who develop constipation 1
- Electrolyte disturbances including hypokalemia, hypocalcemia, and hypomagnesemia can occur with Kayexalate use 2, 1
Efficacy Considerations
- A study showed that 60 g oral doses were more effective than 15 g doses in achieving normokalemia (77% vs 50% success rate) 5
- The potassium-lowering effect correlates with the dose: 15 g, 30 g, and 60 g oral doses reduced serum potassium by approximately 0.39,0.69, and 0.91 mEq/L, respectively 5
- Rectal administration (30 g) showed less potassium reduction (0.22 mEq/L) compared to oral administration 5