LET’S START WITH THE FACTS We know that calcium chloride (CaCl2) provides 3 times more elemental calcium than an equivalent amount of calcium gluconate. So, CaCl2 1 gm = calcium gluconate 3 gm. CLINICAL QUESTIONS Does CaCl2 have better bioavailability than calcium gluconate? Does calcium gluconate have a slower onset of action because it needs hepatic metabolism to release the calcium? MYTH BUSTER Calcium gluconate does NOT require hepatic activation to exert its effect. THE DATA Liver transplant patients [1] Serum ionized calcium levels were measured in 15 hypocalcemic patients during the anhepatic stage of liver transplantation. Half received CaCl2 10 mg/kg, the other half received calcium gluconate 30 mg/kg. Serum concentrations of ionized calcium were determined before and up to 10 min after calcium therapy. Equally rapid increases in calcium concentration after administration of CaCl2 and gluconate were observed, suggesting that calcium gluconate does not require hepatic metabolism for the release of calcium and is as effective as CaCl2 in treating ionic hypocalcemia in the absence of hepatic function. Children and dogs [2] A weird randomized prospective study in both children and dogs compared ionization of CaCl2 and calcium gluconate. The authors conclude that equal elemental calcium doses of calcium gluconate (10%) and CaCl2 (10%) (approximately 3:1), injected over the same period of time: Are equivalent in their ability to raise calcium concentration during normocalcemic states in children and dogs The changes in calcium concentration following calcium administration are short-lived (minutes) The rapidity of ionization seems to exclude hepatic metabolism as an important factor in the dissociation of calcium gluconate Ferrets and in vitro human blood [3] Equimolar quantities of CaCl2 and calcium gluconate produced similar changes in plasma ionized calcium concentration when injected IV into anesthetized ferrets or when added to human blood in vitro. … Continue reading Mythbuster: Calcium Gluconate Raises Serum Calcium as Quickly as Calcium Chloride