does not meet the US RDA for dietary intake of magnesium. The kidneys are very efficient at maintaining body levels; however, if the diet is deficient, or certain medications such as diuretics or proton pump inhibitors are used, or in chronic alcoholism, levels may drop. Low levels of magnesium in blood may be due to not enough magnesium in the diet, the intestines not absorbing enough magnesium, or the kidneys excreting too much magnesium. Deficiencies may be due to the following conditions: Medications Loop and thiazide diuretic use (the most common cause of hypomagnesemia) Antibiotics (i.e. aminoglycoside, amphotericin, pentamidine, gentamicin, tobramycin, viomycin) block resorption in the loop of Henle. 30% of patients using these antibiotics have hypomagnesemia. Long term, high dosage use of proton-pump inhibitors such as omeprazole Other drugs Digitalis, displaces magnesium into the cell. Digitalis causes an increased intracellular concentration of sodium, which in turn increases intracellular calcium by passively increasing the action of the sodium-calcium exchanger in the sarcolemma. The increased intracellular calcium gives a positive inotropic effect. Adrenergics, displace magnesium into the cell Cisplatin, stimulates kidney excretion Ciclosporin, stimulates kidney excretion Mycophenolate mofetil Genetics Gitelman-like diseases, which include the syndromes caused by genetic mutations in SLC12A3, CLNCKB, BSND, KCNJ10, FXYD2, HNF1B or PCBD1. In these diseases, the hypomagnesemia is accompanied by other defects in electrolyte handling such as hypocalciuria and hypokalemia. The genes involved in this group of diseases all encode proteins that are involved in reabsorbing electrolytes (including magnesium) in the distal convoluted tubule of the kidney. Hypercalciuric hypomagnesemic syndromes, which encompass the syndromes caused by mutations in CLDN16, CLDN19, CASR or CLCNKB. In these diseases, reabsorption of divalent cations (such as magnesium and calcium) in the thick ascending limb of Henle's loop of the kidney is impaired. This results in loss of magnesium and calcium in the urine. Mitochondriopathies, especially mutations in the mitochondrial tRNAs MT-TI or MT-TF. Mutations in SARS2, or mitochondrial DNA deletions as seen with Kearns-Sayre syndrome, can also cause hypomagnesemia. Other genetic causes of hypomagnesemia, such as mutations in TRPM6, CNNM2, EGF, EGFR, KCNA1 or FAM111A. Many of the proteins encoded by these genes play a role in the transcellular absorption of magnesium in the distal convoluted tubule. Metabolic abnormalities Insufficient selenium, vitamin D or sunlight exposure, or vitamin B6. Gastrointestinal causes: the distal digestive tract secretes high levels of magnesium. Therefore, secretory diarrhea can cause hypomagnesemia. Thus, Crohn's disease,