What is the drug of choice for hypokalemic periodic paralysis?

Drug of Choice for Hypokalemic Periodic Paralysis

Potassium chloride is the drug of choice for hypokalemic periodic paralysis, both for acute attacks and prevention of recurrent episodes. 1

Acute Management

Potassium Replacement Therapy

• Severity-based approach:

  • Mild hypokalemia (3.0-3.5 mEq/L): Oral potassium supplementation at 20-40 mEq/day divided into 2-3 doses 2
  • Moderate hypokalemia (2.5-3.0 mEq/L): Intravenous potassium chloride at 10-20 mEq/hour 2
  • Severe hypokalemia (<2.5 mEq/L): Immediate IV potassium chloride at 10-20 mEq/hour via peripheral IV (or up to 40 mEq/hour via central line) with continuous cardiac monitoring 2

• Monitoring during acute treatment:

  • Check serum potassium levels within 1-2 days of starting potassium replacement therapy 2
  • Monitor ECG for cardiac abnormalities associated with hypokalemia (U waves, ST depression, T wave flattening) 2
  • Continue cardiac monitoring to detect arrhythmias 2

Prevention of Recurrent Attacks

First-line Prevention

• Oral potassium chloride supplementation - FDA-approved specifically for hypokalemic familial periodic paralysis 1
• Dosing should be adjusted based on serum potassium levels and attack frequency
• Target serum potassium in the 4.0-5.0 mEq/L range 2

Second-line Prevention

• Potassium-sparing diuretics:
  • Triamterene has shown efficacy in preventing attacks in patients who don't respond to or are worsened by acetazolamide 3
  • Spironolactone may be considered as an alternative potassium-sparing diuretic 2

Third-line Prevention

• Acetazolamide - may be effective in some patients by activating calcium-activated potassium channels 4
  • However, acetazolamide can worsen attacks in some patients due to its kaliopenic effect 3
  • Only approximately 50% of patients respond to acetazolamide 5

Important Considerations

Trigger Avoidance

• Educate patients to avoid known triggers:
  • Strenuous exercise
  • High-carbohydrate meals
  • Emotional stress
  • Glucocorticoids (can precipitate attacks) 6

Dietary Recommendations

• Encourage potassium-rich foods (bananas, spinach, avocados) 2
• Avoid high-sodium foods which can lower potassium levels
• Limit carbohydrate intake, especially simple sugars

Monitoring

• Regular monitoring of serum potassium levels is essential
• More frequent monitoring for patients with:
  • Diabetes mellitus
  • Renal dysfunction
  • Heart failure 2

Special Situations

Refractory Cases

• For patients who don't respond to standard therapy, consider:
  • Combination therapy with potassium supplementation and potassium-sparing diuretics
  • Dichlorphenamide has shown efficacy in both hypokalemic and hyperkalemic periodic paralysis 7

Cautions

• Avoid excessive potassium supplementation to prevent rebound hyperkalemia
• Use potassium-sparing diuretics with caution in patients with renal impairment (eGFR <30 mL/min) 2
• Monitor for hypomagnesemia which can perpetuate hypokalemia 2

The management approach should prioritize potassium chloride as the primary treatment, with potassium-sparing diuretics as adjunctive therapy for prevention. While acetazolamide has traditionally been used, evidence shows variable response and potential for worsening symptoms in some patients.