Treatment of Hypokalemia
The treatment of hypokalemia should prioritize oral potassium chloride supplementation (20-60 mEq/day) for mild to moderate cases, with intravenous replacement reserved for severe or symptomatic cases, while addressing the underlying cause and monitoring magnesium levels. 1
Assessment and Classification
- Hypokalemia is defined as serum potassium <3.5 mEq/L, with severity classified as mild (3.0-3.5 mEq/L), moderate (2.5-2.9 mEq/L), or severe (<2.5 mEq/L) 2
- ECG changes (ST depression, T wave flattening, prominent U waves) indicate urgent treatment need 1
- Symptoms may include cardiac arrhythmias, muscle weakness, and in severe cases, paralysis 3
Treatment Approach
Oral Replacement (First-Line)
- Administer oral potassium chloride 20-60 mEq/day to maintain serum potassium in the 4.5-5.0 mEq/L range 1
- FDA-approved indications include treatment of hypokalemia with or without metabolic alkalosis, digitalis intoxication, and hypokalemic familial periodic paralysis 4
- For patients with metabolic acidosis, use alkalinizing potassium salts (potassium bicarbonate, citrate, acetate, or gluconate) instead of potassium chloride 4
Intravenous Replacement
- Reserved for severe hypokalemia (<2.5 mEq/L), symptomatic patients, or those with ECG changes 1, 3
- Administer as slow infusion to prevent cardiac complications; bolus administration is potentially dangerous 2
- For patients with ECG changes, rapid correction with 0.3 mEq potassium/kg/hour may be used until ECG normalizes 5
Special Considerations
Underlying Causes
- Identify and address common causes: diuretic use, gastrointestinal losses, renal losses 3, 6
- For diuretic-induced hypokalemia, consider reducing diuretic dose if possible 4
- For persistent hypokalemia despite supplementation in patients on diuretics, consider adding potassium-sparing diuretics (spironolactone, triamterene, or amiloride) 7, 1
Magnesium Deficiency
- Check and correct magnesium levels, as hypomagnesemia makes hypokalemia resistant to correction 1, 8
- Hypomagnesemia frequently coexists with hypokalemia and can cause renal potassium wasting 2
Cardiac Patients
- Target higher serum potassium levels (4.0-5.0 mEq/L) in patients with heart disease 1, 9
- In patients receiving aldosterone antagonists or ACE inhibitors, potassium supplementation should be reduced or discontinued to avoid hyperkalemia 1
Monitoring
- Verify potassium level with repeat sample to rule out fictitious hypokalemia from hemolysis 1
- Recheck potassium levels 1-2 weeks after each dose adjustment, at 3 months, and subsequently at 6-month intervals 1
- For patients using potassium-sparing diuretics, monitor every 5-7 days until potassium values are stable 7, 1
- Monitor blood pressure, renal function, and electrolytes 1-2 weeks after initiating therapy or changing doses 1
Potential Complications and Pitfalls
- Solid oral dosage forms of potassium chloride can produce ulcerative and/or stenotic lesions of the gastrointestinal tract; discontinue immediately if severe vomiting, abdominal pain, distention, or gastrointestinal bleeding occurs 4
- Excessive potassium supplementation can cause hyperkalemia 1
- Failing to address magnesium deficiency when treating hypokalemia can make potassium repletion difficult 2
- Administering digoxin before correcting hypokalemia significantly increases the risk of life-threatening arrhythmias 1