What is the treatment for severe hypocalcemia (low calcium levels)?

Treatment of Severe Hypocalcemia

For severe hypocalcemia, intravenous calcium chloride is the preferred first-line treatment due to its higher elemental calcium content, followed by calcium supplementation and vitamin D therapy based on the underlying cause. 1

Acute Management of Severe Hypocalcemia

Intravenous Calcium Administration

• Calcium chloride (preferred option):

  • Dosage: 20 mg/kg IV/IO (0.2 mL/kg for 10% CaCl₂) 2
  • Contains 270 mg of elemental calcium per 10 mL of 10% solution 2
  • Preferred for critically ill patients due to more rapid increase in ionized calcium 2
  • Administer by slow push for cardiac arrest; infuse over 30-60 minutes for other indications 2

• Calcium gluconate (alternative option):

  • Dosage: 4g calcium gluconate infused at 1g/hour 1, 3
  • Contains only 90 mg of elemental calcium per 10 mL of 10% solution 2
  • Effectively increases ionized calcium from 0.90 to 1.16 mmol/L in critically ill trauma patients 3
  • Dilute in 5% dextrose or normal saline prior to administration 4

Administration Guidelines

• For bolus administration:
  • Dilute to concentration of 10-50 mg/mL
  • Maximum infusion rate: 200 mg/minute for adults, 100 mg/minute for pediatric patients 4
• For continuous infusion:
  • Dilute to concentration of 5.8-10 mg/mL 4
• Monitor heart rate during administration; stop if symptomatic bradycardia occurs 2
• Central venous catheter administration is preferred; extravasation through peripheral IV may cause severe skin/tissue injury 2

Chronic Management

Oral Calcium Supplementation

• Calcium carbonate: 1000-2000 mg elemental calcium daily in divided doses 1
• Calcium citrate: Better absorbed, especially when taken between meals 1

Vitamin D Therapy

• Cholecalciferol (Vitamin D3): 800-1000 IU daily 1
• Active vitamin D (calcitriol): For severe cases or hypoparathyroidism 1

Special Considerations

• For hypoparathyroidism: Consider recombinant human PTH(1-84) for difficult-to-control hypocalcemia 1, 5, 6
• For renal impairment: Start at lowest dose range and monitor serum calcium every 4 hours 4

Monitoring

• Acute treatment: Monitor ionized calcium levels frequently 1
  • Target: Maintain ionized calcium above 0.9 mmol/L 2, 1
  • Ionized calcium levels below 0.8 mmol/L are associated with cardiac dysrhythmias 2
• Continuous monitoring: ECG and vital signs during IV calcium administration 4
• Long-term: Check calcium levels every 3-6 months until stable, then annually 1
• Monitor 25-hydroxyvitamin D levels with target >30 ng/mL 1

Potential Complications

• Overcorrection leading to hypercalcemia 1
• Calcinosis cutis and tissue necrosis with extravasation of IV calcium 1, 4
• Drug interactions: Avoid concurrent use with ceftriaxone (risk of precipitates) 1, 4
• Caution with cardiac glycosides due to increased risk of arrhythmias 1

Clinical Pearls

• Calculate corrected calcium if using total calcium measurement: Corrected calcium (mg/dL) = Total calcium (mg/dL) + 0.8 × [4 - Serum albumin (g/dL)] 1
• Ionized calcium is pH-dependent; maintain above 0.9 mmol/L during massive transfusion 1
• Symptoms of acute hypocalcemia include neuromuscular irritability, tetany, seizures, and cardiac dysrhythmias 1, 7