Magnesium Correction Guidelines

Cardiac Considerations

The American College of Cardiology recommends administering IV magnesium sulfate for recurrent torsades de pointes with acquired QT prolongation, regardless of baseline magnesium level, with a target of repleting magnesium to ≥2.0 mmol/L (or ≥2.0 mg/dL) as an anti-torsadogenic measure 1
For patients with acute myocardial infarction, the American College of Cardiology suggests giving magnesium sulfate as needed to replete magnesium deficits for 24 hours after the first 24 hours 3

In patients with high-output stoma or short bowel syndrome, the first step is to correct sodium and water depletion with IV saline to address secondary hyperaldosteronism before magnesium supplementation, as hyperaldosteronism increases renal magnesium wasting 2
For patients on continuous renal replacement therapy (CRRT), using dialysis solutions containing magnesium can help prevent hypomagnesemia, which occurs in 60-65% of critically ill patients on CRRT 4

The American College of Cardiology and other guideline societies emphasize the importance of assessing renal function before initiating magnesium supplementation, as creatinine clearance <20 mL/min is an absolute contraindication due to the risk of life-threatening hypermagnesemia 2
During magnesium infusion, it is crucial to monitor for signs of magnesium toxicity, including hypotension, bradycardia, respiratory depression, and loss of deep tendon reflexes, and to have calcium chloride immediately available to reverse magnesium toxicity if needed 2