Management of Acute Hypomagnesemia

Evaluation and Preparation

The American College of Physicians recommends verifying renal function before initiating magnesium supplementation, as supplementation should be avoided if creatinine clearance is <20 mL/min due to the risk of potentially fatal hypermagnesemia 1
The European Society of Intensive Care Medicine suggests correcting dehydration and sodium depletion first, as hypovolemia causes secondary hyperaldosteronism that increases renal losses of magnesium, making supplementation ineffective until corrected 1
The National Institute of Diabetes and Digestive and Kidney Diseases recommends evaluating associated electrolytes, as hypomagnesemia causes refractory hypocalcemia and hypokalemia that will not respond until magnesium is normalized 1

The American Heart Association recommends intravenous magnesium sulfate for severe or symptomatic hypomagnesemia, with a dose of 1-2 g (8-16 mEq) in bolus over 5-15 minutes, followed by continuous infusion of 4-6 g (32-48 mEq) over 24 hours 1
The Annals of Oncology suggests that manifestations requiring urgent intravenous treatment include convulsions, tetany, or severe neuromuscular hyperexcitability 2
The American College of Cardiology recommends intravenous magnesium sulfate for arrhythmias, torsades de pointes, or QTc >500 ms 1

The European Society of Gastroenterology recommends rehydrating with saline solution to eliminate secondary hyperaldosteronism in patients with gastrointestinal losses (diarrhea, stomas, short bowel syndrome) 1
The National Kidney Foundation suggests using dialysis solutions containing magnesium to prevent continuous losses in patients undergoing continuous renal replacement therapy 1, 3

The American College of Physicians recommends monitoring for signs of magnesium toxicity (levels >5.5 mEq/L), including loss of deep tendon reflexes, decreased respiratory rate, hypotension, and bradycardia 1
The European Society of Intensive Care Medicine suggests having calcium chloride available as an antidote to reverse toxicity if necessary 3
The National Institute of Diabetes and Digestive and Kidney Diseases recommends monitoring serum magnesium, calcium, and potassium levels, as well as renal function and resolution of clinical symptoms 1

The American College of Physicians recommends avoiding failure to correct hypovolemia first, as magnesium supplementation will be ineffective if secondary hyperaldosteronism persists 1
The European Society of Intensive Care Medicine suggests avoiding attempting to correct hypokalemia or hypocalcemia without normalizing magnesium first, as these alterations are refractory until magnesium is corrected 1