Calcium
Ca2+
What it isElemental mineral for bone mineralization and neuromuscular function; supplementation and hypocalcemia.
Why this oneThe carbonate form is cheapest and best absorbed with food; the citrate form works without acid, so it is the choice on a PPI.
What limits itConstipation, and it binds levothyroxine, quinolones and iron — separate dosing. Absorption caps at about 500 mg per dose.
FDA label
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| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Acute symptomatic hypocalcemia | Adults | 1,000-2,000 mg IV bolus (diluted; rate <=200 mg/min); repeat q6h PRN, or continuous infusion initiated at 5.4-21.5 mg/kg/h | Individualized to symptoms and serum calcium | Bolus rate <=200 mg/min |
| Acute symptomatic hypocalcemia | Peds >1 mo to <17 yr | 29-60 mg/kg IV bolus (rate <=100 mg/min); repeat q6h PRN, or infusion initiated at 8-13 mg/kg/h | Individualized to symptoms and serum calcium | Bolus rate <=100 mg/min |
| Acute symptomatic hypocalcemia | Neonates <=1 mo | 100-200 mg/kg IV bolus (rate <=100 mg/min); repeat q6h PRN, or infusion initiated at 17-33 mg/kg/h | Individualized to symptoms and serum calcium | Bolus rate <=100 mg/min |
Renal Initiate at lowest dose of recommended range; monitor serum calcium q4h
Hepatic Undefined
100 mg calcium gluconate contains 9.3 mg (0.465 mEq) elemental calcium; long-term-use safety not established
Instructions
- Dilute in 5% dextrose or normal saline before use (bolus 10-50 mg/mL; infusion 5.8-10 mg/mL); use immediately
- Administer IV via secure line - extravasation can cause calcinosis cutis and tissue necrosis
- Monitor vitals and ECG during administration
- Measure serum calcium q4-6h (intermittent dosing) or q1-4h (continuous infusion)
- Do not mix with ceftriaxone, minocycline, or fluids containing phosphate or bicarbonate
Contraindications
- Hypercalcemia
- Neonates (<=28 days) receiving ceftriaxone (fatal ceftriaxone-calcium precipitates)
Cautions
- Arrhythmias with cardiac glycosides - avoid; if unavoidable give slowly in small amounts with ECG monitoring
- Ceftriaxone-calcium precipitates: contraindicated in neonates; in others give sequentially with line flush, never via Y-site
- Tissue necrosis and calcinosis cutis (with or without extravasation) - stop infusion at site if it occurs
- Hypotension, bradycardia, arrhythmias with rapid IV administration - dilute and infuse slowly with ECG
- Aluminum content (up to 400 mcg/L) - toxicity risk with renal impairment or prolonged administration
- Elderly: start at low end of dose range
Adverse reactions
- Local soft tissue inflammation and necrosis, calcinosis cutis, calcification (extravasation) - most common
- Vasodilation
- Hypotension
- Bradycardia
- Cardiac arrhythmia
- Syncope
- Cardiac arrest
Pregnancy Limited data insufficient to assess risk; maternal hypocalcemia itself risks spontaneous abortion, premature/dysfunctional labor, possibly preeclampsia
Lactation Calcium is a natural milk component; unknown whether IV calcium gluconate alters milk calcium; no data on breastfed infant or milk production
NO BOXED WARNINGS
Principal riskConstipation; binds other drugs in the gut
Classes and tags
Clinical profile
Mechanism of action: Calcium ballicule
