What is the treatment for hypocalcemia?

Treatment of Hypocalcemia

Acute Symptomatic Hypocalcemia

For acute symptomatic hypocalcemia, administer intravenous calcium chloride 10 mL of 10% solution (270 mg elemental calcium) over 2-5 minutes with continuous ECG monitoring, as this is the preferred agent over calcium gluconate due to three times higher elemental calcium content. 1

Immediate IV Calcium Administration

• Calcium chloride is superior to calcium gluconate because 10 mL of 10% calcium chloride contains 270 mg elemental calcium versus only 90 mg in the same volume of calcium gluconate 1, 2, 3
• Calcium chloride is particularly preferred in patients with liver dysfunction due to faster release of ionized calcium 2
• Administer slowly and DO NOT exceed 200 mg/minute in adults or 100 mg/minute in pediatric patients 4
• Continuous ECG monitoring is mandatory during administration to detect cardiac arrhythmias 1, 4
• Symptoms resolve within minutes of IV calcium administration 1

Alternative: Calcium Gluconate

• If calcium chloride is unavailable, use calcium gluconate 10% solution 15-30 mL IV over 2-5 minutes 1
• For pediatric patients, calcium gluconate dosing is 50-100 mg/kg IV slowly with ECG monitoring 1
• Dilute calcium gluconate to 10-50 mg/mL concentration prior to bolus administration 4
• For continuous infusion, dilute to 5.8-10 mg/mL concentration 4

Critical Safety Measures

• Never administer calcium through the same IV line as sodium bicarbonate due to precipitation risk 1, 3
• Use a secure intravenous line to avoid calcinosis cutis and tissue necrosis from extravasation 4
• Ceftriaxone and IV calcium are contraindicated in neonates ≤28 days due to fatal ceftriaxone-calcium precipitates 4
• Avoid calcium administration in patients on cardiac glycosides (digoxin) due to synergistic arrhythmia risk; if necessary, administer slowly with close ECG monitoring 4

Essential Concurrent Correction

• Check and correct hypomagnesemia immediately, as hypocalcemia cannot be adequately treated without correcting magnesium first (present in 28% of hypocalcemic patients) 1
• Administer magnesium sulfate 1-2 g IV bolus immediately for symptomatic patients with concurrent hypomagnesemia, followed by calcium replacement 1
• Hypomagnesemia causes hypocalcemia through impaired PTH secretion and end-organ PTH resistance 1

Monitoring During Acute Treatment

• Measure ionized calcium every 4-6 hours during intermittent infusions 4
• Measure ionized calcium every 1-4 hours during continuous infusion 4
• Monitor ionized calcium continuously during massive transfusion, as citrate in blood products binds calcium 1
• Hypocalcemia within 24 hours of critical bleeding predicts mortality better than fibrinogen, acidosis, or platelet count 1

Chronic Hypocalcemia Management

Daily calcium carbonate (1-2 g three times daily) plus vitamin D supplementation (400-2000 IU/day) forms the foundation of chronic hypocalcemia treatment, with careful titration to maintain serum calcium in the low-normal range (8.4-9.5 mg/dL) to avoid hypercalciuria and renal complications. 1, 2

Oral Calcium Supplementation

• Calcium carbonate is the preferred formulation as it contains the highest percentage of elemental calcium 2
• Total elemental calcium intake (including dietary sources) should not exceed 2,000 mg/day 1
• For CKD patients, elemental calcium from calcium-based phosphate binders should not exceed 1,500 mg/day 1

Vitamin D Supplementation

• For vitamin D deficiency (25-hydroxyvitamin D <30 ng/mL), supplement with ergocalciferol (vitamin D2) or cholecalciferol (vitamin D3) 2
• Standard dosing: vitamin D3 400-2000 IU/day for chronic hypocalcemia 1, 2
• For severe or refractory hypocalcemia with elevated PTH, use hormonally active vitamin D metabolites (calcitriol) up to 2 mcg/day 1, 2
• Calcitriol typically requires endocrinologist consultation 1

Target Calcium Levels

• Maintain corrected total serum calcium in the low-normal range (8.4-9.5 mg/dL or 2.10-2.37 mmol/L) 1, 2
• This minimizes hypercalciuria risk while preventing symptoms 1, 5
• Normal ionized calcium ranges from 1.1 to 1.3 mmol/L 2

Monitoring Requirements

• Measure corrected total calcium and phosphorus at least every 3 months in CKD patients 1
• Regularly monitor pH-corrected ionized calcium, magnesium, PTH, and creatinine 1, 2
• Maintain calcium-phosphorus product <55 mg²/dL² to prevent vascular calcification 1
• Targeted monitoring is critical during vulnerable periods: perioperatively, perinatally, during pregnancy, and during acute illness 1, 2

Critical Safety Warnings

• Avoid over-correction, which causes iatrogenic hypercalcemia, renal calculi, and renal failure 1, 2, 3
• Symptoms of hypercalcemia develop when total serum calcium ≥12 mg/dL and include depression, weakness, confusion, hallucinations, and seizures 4
• Use caution when phosphate levels are high due to calcium phosphate precipitation risk in tissues 1

Special Population Considerations

Post-Parathyroidectomy Patients

• Measure ionized calcium every 4-6 hours for the first 48-72 hours after surgery, then twice daily until stable 1
• Initiate calcium gluconate infusion at 1-2 mg elemental calcium/kg/hour if ionized calcium falls below 0.9 mmol/L 1
• When oral intake is possible, provide calcium carbonate 1-2 g three times daily plus calcitriol up to 2 mcg/day 1

22q11.2 Deletion Syndrome (DiGeorge Syndrome)

• 80% have lifetime history of hypocalcemia due to hypoparathyroidism, which may arise or recur at any age despite apparent childhood resolution 1, 2
• Daily calcium and vitamin D supplementation recommended for all adults with this condition 1, 3
• Avoid alcohol and carbonated beverages (especially colas) as they worsen hypocalcemia 1
• Heightened surveillance required during biological stress: surgery, childbirth, infection 1

CKD and Dialysis Patients

• For intensive hemodialysis, use dialysate calcium ≥1.50 mmol/L (3.0 mEq/L) to maintain neutral or positive calcium balance 1
• Higher dialysate calcium (1.75 mmol/L or 3.5 mEq/L) indicated if PTH is elevated and increasing or alkaline phosphatase is rising 1
• In CKD patients on calcimimetics, mild to moderate hypocalcemia may not require aggressive correction, though the 2025 KDIGO Controversies Conference shifted away from permissive hypocalcemia due to severe hypocalcemia risk (7-9% of patients) 1

Renal Impairment

• Initiate calcium gluconate at the lowest recommended dose and monitor serum calcium every 4 hours 4

Pregnancy and Lactation

• Maternal hypocalcemia increases spontaneous abortion, premature labor, and preeclampsia risk 4
• Infants born to hypocalcemic mothers can have fetal/neonatal hyperparathyroidism, skeletal demineralization, and neonatal seizures 4
• Monitor infants for neuromuscular irritability, apnea, cyanosis, and cardiac rhythm disorders 4

Pediatric Patients

• Calcium gluconate dosing: 50-100 mg/kg IV slowly with ECG monitoring for acute symptomatic hypocalcemia 1
• Do not exceed infusion rate of 100 mg/minute in pediatric patients 4
• Contraindication: Concomitant ceftriaxone and IV calcium in neonates ≤28 days due to fatal precipitates 4
• Premature neonates are at risk for aluminum toxicity (this product contains up to 400 mcg/mL aluminum) 4

Underlying Cause-Specific Treatment

Hypoparathyroidism

• Calcium and vitamin D must be carefully titrated to keep serum calcium in low-normal range to minimize hypercalciuria 1, 5
• Recombinant human PTH(1-84) is FDA and EMA approved for hypoparathyroidism, reducing calcium and vitamin D requirements 6
• PTH(1-84) reserved for patients with inadequate control on conventional therapy due to high cost 6

Vitamin D Deficiency

• Correct deficiency with ergocalciferol or cholecalciferol supplementation 2
• Target 25-hydroxyvitamin D levels ≥30 ng/mL 1

Massive Transfusion

• Continuous IV calcium replacement required due to citrate-mediated chelation (each unit contains ~3g citrate) 1
• Citrate metabolism impaired by hypoperfusion, hypothermia, and hepatic insufficiency, requiring more aggressive replacement 1
• Monitor ionized calcium continuously during massive transfusion 1

Tumor Lysis Syndrome

• Administer calcium gluconate 50-100 mg/kg IV slowly with ECG monitoring 1
• Use extreme caution when phosphate levels are high due to calcium phosphate precipitation risk 1