Kayexalate Dosing for Potassium 6.4 mEq/L
For a potassium level of 6.4 mEq/L, administer 30 grams of Kayexalate (sodium polystyrene sulfonate) orally, as this represents severe hyperkalemia requiring prompt treatment with a dose that provides clinically meaningful potassium reduction while minimizing the risk of persistent hyperkalemia. 1, 2, 3
Rationale for 30-Gram Dose
A potassium level of 6.4 mEq/L is classified as severe hyperkalemia (>6.0 mEq/L), which requires prompt multi-pronged treatment due to cardiac arrhythmia risk. 1, 4
The FDA-approved dosing range for oral Kayexalate is 15-60 grams daily, administered as 15-gram doses one to four times daily. 2
Research demonstrates a clear dose-response relationship: 15 grams reduces potassium by approximately 0.39 mEq/L, 30 grams by 0.69 mEq/L, and 60 grams by 0.91 mEq/L. 3
With your starting potassium of 6.4 mEq/L, a 30-gram dose would be expected to reduce potassium by approximately 0.7 mEq/L, bringing the level to approximately 5.7 mEq/L—still elevated but significantly safer. 3
A 15-gram dose would only reduce potassium by 0.4 mEq/L, leaving the patient at 6.0 mEq/L, which remains in the severe hyperkalemia range and increases the risk that 50% of patients will remain hyperkalemic. 3
Critical Concurrent Interventions
Kayexalate should NOT be used as monotherapy for severe hyperkalemia due to its delayed onset of action (hours). 2, 5
You must simultaneously implement acute interventions:
Administer IV calcium gluconate (10-30 mL of 10% solution) immediately to stabilize cardiac membranes if any ECG changes are present (peaked T waves, widened QRS, prolonged PR interval). 1, 4
Give 10 units regular insulin IV with 50 mL of 50% dextrose (D50) to shift potassium intracellularly within 30-60 minutes. 4
Consider nebulized albuterol 20 mg in 4 mL for additive potassium-lowering effect. 4
Kayexalate works by eliminating potassium from the body (onset over several hours), complementing the rapid but temporary effects of insulin/glucose and beta-agonists. 1
Administration Guidelines
Suspend the 30-gram dose in 90-120 mL of water or syrup (approximately 3-4 mL liquid per gram of resin). 2
Administer with the patient in an upright position to reduce aspiration risk. 2
Give Kayexalate at least 3 hours before or after other oral medications (6 hours if gastroparesis is present) due to drug binding in the GI tract. 2, 6
Do not heat the suspension, as this alters the resin's exchange properties. 2
Monitoring Requirements
Check serum potassium within 24 hours after Kayexalate administration to assess response. 1
Monitor for hypokalemia, hypomagnesemia, and hypocalcemia, as Kayexalate is not totally selective for potassium. 1, 2
Each 15-gram dose contains 1,500 mg (60 mEq) of sodium, so a 30-gram dose delivers 3,000 mg sodium—use caution in heart failure patients and monitor for fluid overload. 1, 2
Critical Safety Considerations
Avoid concomitant sorbitol administration, as this combination is associated with intestinal necrosis, some fatal. 2
Use only in patients with normal bowel function—avoid in those with constipation, inflammatory bowel disease, ischemic colitis, or post-surgical ileus. 2
Consider newer potassium binders (patiromer or sodium zirconium cyclosilicate) if available, as they have better safety profiles than Kayexalate. 1, 6
Discontinue Kayexalate if constipation develops, as this increases the risk of serious GI complications. 2
Why Not 15 Grams or 60 Grams?
15 grams is insufficient for K+ 6.4 mEq/L: Research shows 50% of patients receiving 15 grams remain hyperkalemic versus 23% with 60 grams, and the expected 0.4 mEq/L reduction leaves potassium dangerously elevated at 6.0 mEq/L. 3
60 grams may be excessive as initial therapy: While it provides the greatest reduction (0.91 mEq/L), starting with 30 grams allows assessment of response before escalating, minimizes sodium load (3,000 vs 6,000 mg), and reduces GI adverse effects. 2, 3
You can repeat the 30-gram dose in 6 hours if potassium remains >6.0 mEq/L after initial treatment and acute interventions. 1, 2