Magnesium: The Neglected Electrolyte? A Clinical Review

Abstract

Magnesium, Mg 2+ , is the second most abundant intracellular cation after potassium and the fourth most abundant in the body. It was first isolated in 1808 by the English chemist, Sir Humphrey Davy . Magnesium is essential to numerous biochemical reactions. It modulates key physiological proc esses such as metabolic biochemistry, nucleic acid synthesis, receptor-binding and ion flux. The western diet falls short of the recommended daily allowance of 4.5 mg/Kg/day and important dietary sources are seeds, grains, nuts and green vegetables. It is used as a therapeutic agent in a broad range of pathologies : neurological, cardiovascular, respiratory, gastrointestinal and obstet ric. The pharmacokinetics and pharmacodynamics of magnesium, as a drug, are not well under stood. Despite its fundamental importance to human physiology, it remains an electrolyte that is not routinely measured as part of the “urea & electrolytes” test and is the most overlooked elec trolyte deficiency in hospital inpatients. This review will summarise the importance of magnesium homeostasis, its pharmacological effects and clinical applications.