How to correct hypokalemia (low potassium levels) and hyperkalemia (high potassium levels)?

Management of Hypokalemia and Hyperkalemia

Hypokalemia Correction

Severity Classification and Initial Assessment

For hypokalemia, target serum potassium levels of 4.0-5.0 mEq/L in all patients, with cardiac patients requiring the higher end (4.5-5.0 mEq/L) to prevent arrhythmias. 1, 2

Severity categories guide treatment urgency 1, 3:

• Severe (<2.5 mEq/L): Requires immediate IV correction with cardiac monitoring due to high risk of ventricular arrhythmias, torsades de pointes, and cardiac arrest 1, 3
• Moderate (2.5-2.9 mEq/L): Prompt correction needed; associated with ECG changes (ST depression, T-wave flattening, prominent U waves) 1, 3
• Mild (3.0-3.5 mEq/L): Oral replacement typically sufficient unless high-risk features present 1, 4

Critical First Step: Check and Correct Magnesium

Before treating hypokalemia, always check magnesium levels—hypomagnesemia is the most common reason for treatment failure and makes hypokalemia completely resistant to correction. 1, 2 Target magnesium >0.6 mmol/L (>1.5 mg/dL) using organic salts (aspartate, citrate, lactate) rather than oxide or hydroxide for superior bioavailability 1.

Oral Potassium Replacement (Preferred Route)

For stable patients without severe symptoms or ECG changes 1, 2, 5:

Dosing:

• Start with potassium chloride 20-40 mEq daily, divided into 2-3 doses 1
• Maximum 60 mEq/day without specialist consultation 1
• Divide doses throughout the day to prevent GI intolerance and avoid rapid fluctuations 1

Expected response: Each 20 mEq dose increases serum potassium by approximately 0.25-0.5 mEq/L 1

Monitoring protocol 1:

• Recheck potassium and renal function within 3-7 days after starting
• Continue monitoring every 1-2 weeks until stable
• Then at 3 months, subsequently every 6 months
• More frequent monitoring needed with renal impairment, heart failure, diabetes, or medications affecting potassium

Intravenous Potassium Replacement

Indications for IV correction 1, 2, 3:

• Severe hypokalemia (K+ ≤2.5 mEq/L)
• ECG abnormalities or active cardiac arrhythmias
• Severe neuromuscular symptoms (paralysis, respiratory impairment)
• Non-functioning gastrointestinal tract
• Patients on digoxin with any degree of hypokalemia

IV administration guidelines 1, 2, 6:

• Maximum peripheral concentration: 40 mEq/L 2
• Standard rate: 10-20 mEq/hour via peripheral line 1
• Concentrated infusions (200 mEq/L) at 20 mEq/hour can be used via central line in ICU settings with continuous cardiac monitoring 6
• Rates exceeding 20 mEq/hour should only be used in extreme circumstances with continuous cardiac monitoring 1

Recheck potassium within 1-2 hours after IV correction to ensure adequate response and avoid overcorrection 1

Special Clinical Scenarios

Diabetic Ketoacidosis 1, 2:

• Delay insulin therapy until K+ ≥3.3 mEq/L to prevent life-threatening arrhythmias 2
• Add 20-30 mEq/L potassium (2/3 KCl, 1/3 KPO4) to IV fluids once K+ <5.5 mEq/L with adequate urine output 1
• Typical total body deficit: 3-5 mEq/kg body weight despite normal initial serum levels 1

Diuretic-induced hypokalemia 1:

• Potassium-sparing diuretics are superior to chronic oral supplementation for persistent diuretic-induced hypokalemia 1
• Options: Spironolactone 25-100 mg daily, amiloride 5-10 mg daily, or triamterene 50-100 mg daily 1, 2
• Check potassium and creatinine 5-7 days after initiation, then every 5-7 days until stable 1
• Avoid in chronic kidney disease with GFR <45 mL/min 1

Critical Medication Considerations

Medications to avoid or adjust during hypokalemia 1:

• Digoxin: Question orders in severe hypokalemia—dramatically increases risk of life-threatening arrhythmias 1
• Most antiarrhythmic agents: Avoid except amiodarone and dofetilide 1
• Thiazide and loop diuretics: Hold or reduce until hypokalemia corrected 1
• NSAIDs: Avoid—cause sodium retention and worsen treatment efficacy 1

Medications reducing need for supplementation 1:

• ACE inhibitors and ARBs reduce renal potassium losses—routine supplementation may be unnecessary and potentially harmful 1
• When initiating aldosterone antagonists, reduce or discontinue potassium supplements to avoid hyperkalemia 1

Common Pitfalls in Hypokalemia Management

1. Never supplement potassium without checking and correcting magnesium first—this is the most common reason for treatment failure 1
2. Failing to address underlying causes (correct sodium/water depletion first in GI losses, as hypoaldosteronism paradoxically increases renal potassium losses) 1, 2
3. Not monitoring frequently enough after initiating therapy, especially with concurrent RAAS inhibitors 1
4. Administering digoxin before correcting hypokalemia 1
5. Using potassium citrate instead of potassium chloride—worsens metabolic alkalosis 1

---

Hyperkalemia Correction

Severity Classification and ECG Assessment

Hyperkalemia severity and treatment urgency are determined by both serum level and ECG changes 5, 7, 3:

• Mild (5.0-5.5 mEq/L): Usually asymptomatic, medication adjustment often sufficient 1
• Moderate (5.5-6.5 mEq/L): Requires treatment, ECG monitoring 1, 5
• Severe (>6.5 mEq/L): Medical emergency with risk of cardiac arrest 1, 5

ECG changes indicating urgent treatment 5, 3:

• Peaked T-waves (earliest sign)
• Loss of P-waves
• Widened QRS complex
• ST-segment depression
• Prolonged QT interval
• Late: sine wave pattern, ventricular fibrillation, asystole

Emergency Treatment Algorithm for Severe Hyperkalemia

Step 1: Cardiac Membrane Stabilization (if ECG changes present) 1:

• IV calcium gluconate 10%: 15-30 mL over 2-5 minutes 1
• Onset: 1-3 minutes 1
• Does NOT lower potassium but protects heart from arrhythmias 1
• Recheck ECG in 5-10 minutes; repeat dose if no improvement 1
• Caution: Use carefully in digitalized patients—too rapid lowering of potassium can cause digitalis toxicity 5, 7

Step 2: Shift Potassium Intracellularly (acute lowering) 1, 5, 7:

Insulin + Glucose (preferred):

• 10-20 units regular insulin in 300-500 mL of 10% dextrose over 1 hour 5, 7
• Onset: 30-60 minutes 1
• Duration: 2-4 hours 1
• Recheck potassium within 1-2 hours after administration 1

Inhaled β-agonists (albuterol):

• 10-20 mg nebulized 3
• Onset: 30-60 minutes 1
• Can be used adjunctively with insulin/glucose 3

Step 3: Remove Potassium from Body 1, 5, 7:

Newer potassium binders (preferred):

• Patiromer (Veltassa) or sodium zirconium cyclosilicate (Lokelma) 1
• Onset: ~1 hour for SZC 1
• Superior to sodium polystyrene sulfonate (SPS) due to better efficacy and safety profile 1
• Allow continuation of cardioprotective RAAS inhibitors 1

Sodium polystyrene sulfonate:

• Reserved for subacute treatment when newer agents unavailable 3
• Associated with serious GI adverse effects 1

Hemodialysis:

• For refractory hyperkalemia, severe renal impairment, or K+ >6.5 mEq/L unresponsive to medical therapy 5, 7

Chronic Hyperkalemia Management

For patients with recurrent hyperkalemia on RAAS inhibitors 1:

K+ 4.5-5.0 mEq/L:

• Initiate or up-titrate RAAS inhibitor therapy 1
• Monitor closely 1

K+ >5.0-<6.5 mEq/L:

• Initiate potassium-lowering agent (patiromer or SZC) 1
• Continue RAAS inhibitor for cardiovascular/renal protection 1

K+ >6.5 mEq/L:

• Discontinue or reduce RAAS inhibitor immediately 1
• Initiate potassium-lowering agent as soon as K+ >5.0 mEq/L 1

If K+ >5.5 mEq/L on mineralocorticoid receptor antagonists:

• Halve the MRA dose and monitor closely 1

If K+ >6.0 mEq/L:

• Cease MRA therapy 1

Immediate Interventions for All Hyperkalemia

Eliminate potassium sources 5:

1. Stop all potassium-containing foods and medications 5
2. Discontinue potassium-sparing diuretics 5
3. Hold or reduce ACE inhibitors, ARBs 5
4. Avoid NSAIDs and COX-2 inhibitors 1
5. Stop potassium supplements and salt substitutes 1

Dietary modifications 1:

• Limit high-potassium foods (bananas, oranges, potatoes, tomatoes, legumes)
• Avoid salt substitutes containing potassium 1
• Avoid herbal supplements that raise K+ (alfalfa, dandelion, horsetail, nettle) 1

Monitoring Protocol for Hyperkalemia Treatment

Acute phase 1:

• Continuous cardiac monitoring if ECG changes present 1
• Recheck potassium every 2-4 hours during active treatment until stabilized 1
• Monitor for rebound hyperkalemia, especially if transcellular shift was primary mechanism 1

Chronic management 1:

• Check potassium 7-10 days after starting/adjusting RAAS inhibitors in at-risk patients 1
• More frequent monitoring with renal impairment, diabetes, heart failure 1
• When initiating potassium binders: check within 1 week, then weekly during titration, then at 1-2 weeks after stable dose, at 3 months, then every 6 months 1

Critical Caveats in Hyperkalemia Management

1. Monitor closely when initiating potassium-lowering therapy—overcorrection to hypokalemia may be more dangerous than hyperkalemia 1
2. In digitalized patients, avoid rapid potassium lowering—can precipitate digitalis toxicity 5, 7
3. Correct acidosis with sodium bicarbonate if present, but this is adjunctive therapy 5
4. Never give bolus potassium for cardiac arrest suspected to be from hypokalemia—this is ill-advised and potentially fatal 1, 2
5. Extended-release potassium formulations mean absorption and toxic effects may be delayed for hours in overdose 5