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

Treatment of Hypocalcemia

For the treatment of hypocalcemia, intravenous calcium chloride is recommended as the preferred agent for acute symptomatic hypocalcemia, as it contains more elemental calcium (270 mg per 10 mL of 10% solution) compared to calcium gluconate (90 mg per 10 mL of 10% solution). 1, 2, 3

Acute Symptomatic Hypocalcemia Treatment

Intravenous Calcium Administration

• First-line treatment:
  • Calcium chloride 10% solution: 5-10 mL IV (contains 270 mg elemental calcium per 10 mL) 1, 3
  • Calcium gluconate 10% solution: 10-30 mL IV (contains 90 mg elemental calcium per 10 mL) 1, 4
  • Administer slowly: maximum rate of 200 mg/minute in adults, 100 mg/minute in pediatric patients 4

Dosing Guidelines

• For mild hypocalcemia (ionized calcium 1.0-1.12 mmol/L):
  • 1-2 g IV calcium gluconate (effective in 79% of cases) 5
• For moderate to severe hypocalcemia (ionized calcium <1.0 mmol/L):
  • 4 g IV calcium gluconate infused at 1 g/hour (effective in 95% of cases) 6
• For continuous infusion:
  • 1-2 mg of elemental calcium per kg body weight per hour 2
  • For a 70 kg adult: 70-140 mg elemental calcium per hour (1-2 ampules of calcium gluconate) 2

Monitoring

• Monitor ionized calcium levels every 4-6 hours during initial treatment 2
• Target ionized calcium >0.9 mmol/L (equivalent to total calcium of approximately 7.2 mg/dL) 1, 2
• Monitor ECG during administration, especially with rapid infusions 2, 4
• For continuous infusions, check calcium levels every 1-4 hours 2

Transition to Oral Therapy

Once calcium levels begin to stabilize:

• Transition to oral calcium supplementation: calcium carbonate 1-2 g three times daily 2
• Consider adding calcitriol (active vitamin D) up to 2 μg/day to enhance calcium absorption 2
• Total elemental calcium intake should not exceed 2,000 mg/day 2

Special Considerations

Hypocalcemia in Trauma/Massive Transfusion

• Acute hypocalcemia is common in trauma patients receiving massive transfusions due to citrate chelation of calcium 1
• Ionized calcium levels below 0.8 mmol/L are associated with cardiac dysrhythmias and require prompt correction 1

Hypocalcemia in Tumor Lysis Syndrome

• For asymptomatic patients, no intervention is recommended 1
• For symptomatic patients, calcium gluconate 50-100 mg/kg IV administered slowly with ECG monitoring 1
• Use caution with elevated phosphate levels due to risk of calcium phosphate precipitation 1

Renal Impairment

• For patients with renal impairment, start at the lowest recommended dose 2, 4
• Monitor calcium-phosphorus product (should be <55 mg²/dL²) 2
• More frequent monitoring of serum calcium (every 4 hours) 2, 4

Pitfalls and Caveats

1. Avoid rapid administration: Can cause cardiac arrhythmias, hypotension, and cardiac arrest 1, 2

2. Check magnesium levels: Hypomagnesemia can impair PTH secretion and action, making hypocalcemia resistant to treatment 2

3. Calcium administration with hyperphosphatemia: Use caution as this may increase risk of calcium phosphate precipitation in tissues 1

4. Drug incompatibilities: Do not mix calcium with ceftriaxone due to risk of precipitation 4

5. Secure IV access: Administer via secure intravenous line to avoid calcinosis cutis and tissue necrosis 4

6. Laboratory considerations: Laboratory tests may not accurately reflect the effect of hypocalcemia on coagulation cascade as blood samples are citrated and recalcified prior to analysis 1

7. Calcium chloride vs. calcium gluconate: While calcium chloride provides more elemental calcium, calcium gluconate may be preferred for peripheral administration due to less vessel irritation 7

By following these guidelines, hypocalcemia can be effectively managed while minimizing complications associated with both the condition itself and its treatment.