Magnesium Levels and Hypermagnesemia Treatment

Magnesium Levels

• Typical range: 1.4-1.7 mEq/L, 1.7-2.3 mg/dL, 0.7-0.95 mmol/L.
• Note: Institutional ranges may differ slightly.
• High alert medication: Magnesium sulfate.

Hypermagnesemia

• High panic threshold, but fairly common in labor patients with pre-eclampsia.
• Should not be ignored in non-pregnant patients due to decreased renal excretion.
• Worry about cardiac symptoms (QT interval prolongation) when Mg levels exceed 4.

Hypermagnesemia Treatment Goals

• Reduce further intake: Stop magnesium-containing medications and dietary sources. Reduce/discontinue magnesium intake after resolution.
• Reduce complications: Administer IV calcium (100-200 mg elemental calcium over 5-10 minutes) to prevent cardiac/neuromuscular destabilization. Repeat doses as necessary (potentially hourly) as oral calcium is not effective.
• Eliminate excess magnesium: Use forced diuresis (0.9% or 0.45% sodium chloride and loop diuretics) in most patients EXCEPT those with anuria; urgent dialysis utilizing magnesium-free dialysate is necessary for patients requiring dialysis.

Hypomagnesemia

• Symptoms: Mostly asymptomatic; symptomatic when neuromuscular (tetany, twitching, convulsions) or cardiovascular (palpitations, arrhythmias, hypertension, sudden cardiac death).

Hypomagnesemia Treatment (Mild/Moderate):

• Mild/Moderate (≥1 mg/dL): Oral therapy is sufficient; consider IV for those with poor oral tolerance. Administer 1-2 grams IV at 1 gram/hr ( > 1.5 mg/dL) or 2-4 grams over 4-12 hours (1-1.5 mg/dL) reassessing the following morning, or sooner as clinically indicated.

Hypomagnesemia Treatment (Severe):

• Severe (<1 mg/dL): IV therapy is preferred. If hemodynamically unstable, administer 1-2 grams IV over 2-15 minutes; repeat if instability continues.
• Otherwise: Bolus then infusion with 1-2 grams over an hour, followed by 4-8 grams over 12-24 hours until magnesium levels exceed 1 mg/dL..

Oral Magnesium Products (Elemental Mg)

• Magnesium oxide: 242 mg in a 400 mg tablet (65%).
• Magnesium hydroxide: 167 mg in a 400 mg tablet or 5ml oral suspension.
• Magnesium chloride: 64 mg in a 535 mg tablet.
• Magnesium citrate: 48 mg in each 5 ml oral solution.
• Magnesium gluconate: 27 mg in a 500 mg tablet.
• Magnesium lactate: 84 mg in an 84 mg tablet.

Explore the critical information regarding magnesium levels and the management of hypermagnesemia. This quiz delves into typical ranges, treatment goals, and implications for both pregnant and non-pregnant patients. Ensure you understand the importance of monitoring and intervention in cases of elevated magnesium levels.