How to manage hyperkalemia in a patient with improving hyponatremia who is planned to start Lokelma (sodium zirconium cyclosilicate)?

Management of Hyperkalemia in a Patient with Improving Hyponatremia

Start Lokelma (sodium zirconium cyclosilicate) 10g three times daily for 48 hours, then transition to 5-10g once daily for maintenance, while closely monitoring both potassium and sodium levels within 24-48 hours and again at 7 days. 1

Immediate Assessment Priorities

Your patient's potassium of 5.9 mEq/L represents moderate hyperkalemia that requires prompt treatment, but this is not an emergency requiring acute interventions like calcium or insulin unless ECG changes are present 1. Before initiating Lokelma:

• Obtain an ECG immediately to assess for peaked T waves, flattened P waves, prolonged PR interval, or widened QRS complexes—these findings would escalate urgency regardless of the absolute potassium value 1
• Verify this is not pseudohyperkalemia from hemolysis, repeated fist clenching, or poor phlebotomy technique by repeating the measurement with proper technique 1
• Check renal function (eGFR) and assess urine output to determine if the patient has adequate kidney function for potassium excretion 1

Critical Consideration: Sodium Status

Your patient's sodium improved from 125 to 130 mEq/L, which is appropriate correction (not exceeding 8-10 mEq/L per 24 hours to avoid osmotic demyelination). However, sodium is still low at 130 mEq/L 1. This creates a unique challenge:

• Lokelma exchanges sodium for potassium in the GI tract, meaning it will deliver additional sodium to the patient 2, 3
• In your patient with recent severe hyponatremia, this sodium load could theoretically cause overly rapid correction if given at high doses
• Monitor sodium levels closely (within 24-48 hours) after starting Lokelma to ensure correction doesn't exceed safe rates 1

Lokelma Dosing Protocol

For acute correction (K+ 5.9 mEq/L):

• Start with 10g three times daily for 48 hours to rapidly lower potassium into the normal range (3.5-5.0 mEq/L) 1, 3
• This regimen achieves normokalaemia in 84% of patients within 24 hours and 98% within 48 hours 3
• Median time to normalization is 2.2 hours 3

For maintenance therapy:

• Transition to 5-10g once daily after achieving normokalaemia 1, 3
• The 5g dose maintains normokalaemia in 80% of patients, while 10g maintains it in 90% 3
• Titrate based on potassium levels checked at 7-10 days, then monthly for 3 months, then every 6 months 1

Medication Review and Adjustments

Identify and address contributing medications:

• Review for RAAS inhibitors (ACE inhibitors, ARBs, mineralocorticoid antagonists)—do NOT discontinue these life-saving medications at K+ 5.9 mEq/L; instead, use Lokelma to maintain them 1
• Eliminate or reduce: NSAIDs, trimethoprim, heparin, beta-blockers, potassium supplements, salt substitutes 1
• Optimize diuretic therapy with loop or thiazide diuretics (furosemide 40-80 mg daily) if adequate renal function present 1

Monitoring Protocol

Critical timepoints:

• 24-48 hours: Recheck potassium AND sodium to assess response and ensure sodium isn't correcting too rapidly 1, 3
• 7-10 days: Recheck potassium, sodium, and renal function after transitioning to maintenance dosing 1
• Monthly for 3 months, then every 6 months thereafter 1

Watch for hypokalemia: The 10g dose carries a 10% risk of hypokalemia, which may be even more dangerous than hyperkalemia 3, 1

Special Considerations for Your Patient

Advantages of Lokelma in this scenario:

• Rapid onset of action (~1 hour) makes it ideal for moderate hyperkalemia 1
• Effective across all CKD stages, including patients with eGFR <30 mL/min/1.73 m² 4
• Well-tolerated with low rates of serious adverse effects 2, 3
• Allows continuation of RAAS inhibitors if patient is on them for cardio/renoprotection 1, 5

Potential concern with sodium delivery:

• Edema is more common at higher doses (14% at 15g dose vs 2% at placebo) 3
• Given your patient's recent hyponatremia, monitor for signs of volume overload
• The sodium load from Lokelma is generally well-tolerated but requires monitoring in your specific case 2

Common Pitfalls to Avoid

• Don't use sodium bicarbonate unless metabolic acidosis is present (pH <7.35, bicarbonate <22 mEq/L)—it's not indicated for hyperkalemia alone 1
• Don't discontinue RAAS inhibitors at K+ 5.9 mEq/L—only consider temporary reduction if K+ >6.5 mEq/L 1
• Don't rely solely on dietary restriction—it's insufficient for managing K+ 5.9 mEq/L 1
• Don't forget to monitor sodium closely given your patient's recent severe hyponatremia 1
• Don't use older agents like sodium polystyrene sulfonate (Kayexalate)—it has delayed onset, limited efficacy, and risk of bowel necrosis 1