Hypermagnesemia is a state of increased levels of magnesium in blood.

Most common causes of hypermagnesemia include excessive intake of magnesium and insufficient excretion of magnesium by kidneys in patients with kidney failure.  When it comes from increased dietary intake it is most commonly occurring by excessive use of laxatives, such as milk of magnesia or antacid medications. High levels of magnesium are also present in cathartics, commonly used medications for the ease of defecation such as magnesium citrate [1]. Hypermagnesemia along with hyperkalemia and hyperphosphatemia may also occur from the increased cell death and release of the chemical compounds from the dead cells into the blood stream. Such may happen in the states of severe infection and sepsis or large area burns. Other rare causes may include such conditions as hypothyroidism, adrenal insufficiency and lithium toxicity.

Normal level of magnesium in adults is in the range of 1.7-2.3 mg/dL.

The most common manifestations of hypermagnesemia include neurologic symptoms. Generalized muscle weakness and somnolence may be noticed by a patient. A decreased deep tendon reflexes can also be observed by a physician performing neurologic exam. Severe overdose leads to a potentially dangerous breathing problems by paralyzing the muscles that maintain the breathing. Bowel and bladder paralysis resulting in constipation and inability to urinate may be present in cases of very high levels of magnesium intoxication. Other nonspecific symptoms may be observed such as nausea, vomiting and skin flushes. Hypermagnesemia may also interfere with heart electrical functioning causing abnormalities in the heart rhythm. High magnesium levels were also found to lower blood pressure [2], especially when standing up abruptly, which may lead to a brief loss of consciousness and fall.

Treatment of hypermagnesemia is aimed at elimination of excessive magnesium from the body using diuretics and calcium salts.

Furosemide is a diuretic of choice for the treatment of hypermagnesemia as it facilitates the excretion of magnesium by kidneys. Calcium gluconate may be used for acute symptoms as it directly opposes magnesium actions on muscles and nerves. Glucose injections may also be helpful in severe cases as glucose makes excessive magnesium from blood stream to go back into cells. Insulin should be administered with glucose and sugar blood levels monitored to prevent hypoglycemia in such patients.



  1. Jaing TH, Hung IJ, Chung HT, Lai CH, Liu WM, Chang KW. Acute hypermagnesemia: a rare complication of antacid administration after bone marrow transplantation. Clin Chim Acta. 2002;326:201–203.
  2. Clark BA, Browns RS. Unsuspected morbid hypermagnesemia in elderly patients. Am J Nephrol.1992;18:336–43.