Calcium Gluconate

Hyperkalemia rescue - 1–2 g IV over 5–10 min stabilizes the myocardial membrane in life-threatening hyperkalemia; effect begins within 1–3 min and lasts 30–60 min, so always pair with definitive potassium-lowering therapy.

Massive transfusion - Citrate in blood products chelates ionized calcium and can precipitate hypotension, prolonged QT (QT), and coagulopathy; give 1–2 g IV after every 2–4 units of packed red cells or 1 L of fresh frozen plasma, more aggressively in hepatic dysfunction or rapid transfusion.

Calcium channel blocker / beta-blocker overdose - Bolus 1–3 g IV and repeat every 10–20 min as needed alongside high-dose insulin euglycemia therapy and lipid emulsion.

Magnesium toxicity - 1 g IV over 10 min reverses respiratory depression and cardiac effects from magnesium sulfate, especially in obstetric magnesium therapy for preeclampsia.

Calcium chloride vs gluconate - Calcium chloride provides about three times the elemental calcium per gram and acts faster, but is highly caustic and should be given through a central line; calcium gluconate is safer peripherally and is preferred when central access is unavailable.

Line compatibility - Precipitates with sodium bicarbonate and phosphate-containing solutions; flush the line thoroughly between drugs and avoid co-administration through the same lumen.

Management of excessive effect - Stop infusion, give IV fluids and a loop diuretic to enhance renal calcium excretion, and consider calcitonin or hemodialysis for severe symptomatic hypercalcemia.

Drug Interactions - Potentiates digoxin toxicity (use cautiously in digitalized patients); precipitates with ceftriaxone, particularly in neonates; partially antagonizes calcium channel blockers and beta blockers, which is the basis of overdose therapy.

Pediatric Implications - Calcium gluconate 60–100 mg/kg IV (max 3 g) for symptomatic hypocalcemia or hyperkalemia, given over 5–10 min with cardiac monitoring; calcium chloride 20 mg/kg is reserved for emergencies through central or large peripheral access. Do NOT co-administer with ceftriaxone in neonates because of fatal pulmonary and renal precipitation.

Obstetric Implications - Crosses the placenta and is the standard reversal agent for maternal magnesium toxicity in preeclampsia (1 g IV over 10 min). Safe in pregnancy and lactation; useful during obstetric hemorrhage and massive transfusion.

Absolute: hypercalcemia, digoxin toxicity (calcium can precipitate fatal arrhythmia), ventricular fibrillation during routine cardiac arrest (no role in standard adult ACLS).

Relative: sarcoidosis and other granulomatous disease, severe renal impairment with hyperphosphatemia, history of calcium nephrolithiasis.

Caution: patients on digoxin therapy, neonates receiving ceftriaxone, concurrent administration with bicarbonate or phosphate-containing fluids.

Symptomatic hypocalcemia or massive transfusion: 1–2 g (10–20 mL of 10% solution) IV over 10 min; repeat as needed to ionized calcium target.

Life-threatening hyperkalemia: 1–2 g IV over 5–10 min; may repeat after 5 min if ECG changes persist.

Calcium channel blocker or beta-blocker overdose: 1–3 g IV bolus, repeat every 10–20 min as needed.

Magnesium toxicity: 1 g IV over 10 min.

0.5–2 g/hr titrated to serum ionized calcium for ongoing replacement (e.g., during prolonged citrate exposure).

Supplies ionized calcium (Ca2+), which raises the cardiomyocyte threshold potential to antagonize hyperkalemic membrane depolarization, restores excitation-contraction coupling, and supports neuromuscular transmission and coagulation.

Not metabolized; calcium ion is biologically active.

Renal and fecal.

10% calcium gluconate = 100 mg/mL = 0.465 mEq/mL elemental calcium; 1 g (10 mL) supplies roughly 4.65 mEq (93 mg) of elemental calcium.

Calcium chloride 10% supplies about three times more elemental calcium per gram (1 g CaCl2 ≈ 13.6 mEq, 273 mg elemental Ca); use it via central line for in-arrest situations.

Vesicant on extravasation. Apply warm compresses and elevate; do NOT use cold compresses, which worsen vasoconstriction and tissue injury. Hyaluronidase can be considered for severe extravasation.

Incompatible with sodium bicarbonate, phosphate, and many cephalosporins; flush line or use separate access.

Store at room temperature; refrigeration causes crystallization. Inspect for crystals before use.