TY - CHAP M1 - Book, Section TI - Antidotes in Depth A1 - Howland, Mary Ann A2 - Hoffman, Robert S. A2 - Howland, Mary Ann A2 - Lewin, Neal A. A2 - Nelson, Lewis S. A2 - Goldfrank, Lewis R. PY - 2015 T2 - Goldfrank's Toxicologic Emergencies, 10e AB - Calcium is essential to maintain the normal function of the heart, vascular smooth muscle, skeletal system, and the nervous system. It is vital in enzymatic reactions, in neurohormonal transmission, and in the maintenance of cellular integrity.21 The endocrine system maintains calcium homeostasis. Approximately half of the total serum calcium is ionized and active, and the remainder is primarily bound to albumin. Hypercalcemia raises the threshold for nerve and muscle excitation, resulting in muscle weakness, lethargy, cardiac conduction disturbances, and coma.21 Hypocalcemia can result in hyperreflexia, muscle spasms, tetany, seizures, and QT interval prolongation (Chaps. 16 and 19).21 SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/03/28 UR - accesspharmacy.mhmedical.com/content.aspx?aid=1108422748 ER -