Fluids, Electrolytes, Acid-Base Disorders, and Nutrition Support

Salt Form

% Elemental Magnesium Content

Oxide

Carbonate

Hydroxide

Citrate

Lactate

Chloride

Sulfate

Gluconate

Hypermagnesemia

Definition: Serum magnesium concentration greater than 2.4 mg/dL

Signs and symptoms: Hypotension, decreased deep tendon reflexes, cardiovascular manifestations

(e.g., bradycardia, somnolence, muscle paralysis, arrhythmias) generally do not occur until serum

concentrations are greater than 4 mg/dL.

Etiologies: Renal failure or impairment, early post-infusion elevation of serum magnesium

concentration, excessive dosing of magnesium/antacids, post-cathartic use (e.g., magnesium

citrate) – To develop hypermagnesemia, these events usually occur together with renal impairment.

Remove source of magnesium intake.

ii.

Intermittent slow bolus doses of calcium gluconate (2 g) for 5–10 minutes until severe symptoms

abate (the effect of calcium is transient, and repeat therapy may be needed as often as every

hour). The effects of magnesium on neuromuscular and cardiac function are antagonized by

calcium.

iii.

Ventilate the patient, if necessary.

iv.

0.9% sodium chloride infusion with loop diuretic therapy

Hemodialysis