Abstract
Hypermagnesemia is a rare and often iatrogenic condition caused by the administration of magnesium-containing medications. We report 3 cases of severe hypermagnesemia caused by the long-term administration of magnesium oxide for constipation. The serum magnesium levels of the patients exceeded 15 mg/dl and caused shock and coma. Although the patients were treated with intravenous calcium and conventional or continuous hemodialysis, one of them died. Studies have reported that severe hypermagnesemia caused by the administration of magnesium oxide is less common than that caused by the administration of a single dose of any other magnesium-containing medications, such as magnesium citrate or magnesium sulfate, that contain a larger magnesium load. However, the findings in the present cases suggest that long-term administration of magnesium-containing medications with a lower magnesium load can also be a risk factor for severe hypermagnesemia. Hypermagnesemia is difficult to diagnose because of nonspecific symptoms. In addition, it can be fatal if initial diagnosis and treatment have been delayed. Therefore, close observation with serum magnesium measurements according to need should be performed when magnesium-containing cathartics are prescribed to a patient for a long time.
