Adverse effects of calcium administration. Report of two cases.

Calcium chloride, 7 mg/kg, and calcium gluconate, 20 mg/kg, were administered to patients with low or low-normal levels of serum ionized calcium. Both patients had low blood pressure and cardiac index, and did not respond to digitalis, volume expansion, and beta-adrenergic stimulation with dopamine. Administration of calcium rapid increase of serum ionized calcium levels, decrease of serum potassium levels, and development of severe cardiac arrhythmias. Atrioventricular dissociation and further fall of cardiac index and blood pressure were common features of both cases. Administration of exogenous calcium can cause severe complications, even when theoretically indicated.