Iatrogenic magnesium overdose: two case reports.

We report two cases of iatrogenic intravenous magnesium overdose. Both patients presented to the emergency department in alcohol withdrawal, and during the course of their therapy were ordered to receive 2 g of magnesium sulfate intravenously. The patients were erroneously given 20 g of magnesium sulfate, causing cardiac arrest in both cases. The patients were both successfully resuscitated. One patient was discharged neurologically intact and the other died three days later. Review of the literature identified one previous report of iatrogenic overdose of intravenous magnesium causing death. Hypermagnesemia is a rare occurrence, particularly in the absence of renal failure. The cause is often iatrogenic. The major life-threatening clinical manifestations are cardiac conduction delays, asystole, apnea, and coma. A particular hazard of intravenous magnesium therapy is the variety of units of measurement used in written orders and on drug labels. This can easily lead to errors in drug administration.