Correction of Calcium and Magnesium Imbalances
For calcium correction, calcium chloride is preferred over calcium gluconate due to higher elemental calcium content, while magnesium sulfate is the treatment of choice for magnesium deficiency. 1, 2
Calcium Correction
Intravenous Calcium Options
- Calcium chloride (10%) is the preferred agent for correction of hypocalcemia, particularly in emergency situations, as 10 mL contains 270 mg of elemental calcium 1
- Calcium gluconate (10%) contains only 90 mg of elemental calcium per 10 mL, making it less efficient for rapid correction 1
- For hypocalcemia correction, administer calcium chloride 10% at 5-10 mL or calcium gluconate 10% at 15-30 mL IV over 2-5 minutes 1
Specific Clinical Scenarios for Calcium Administration
- Calcium is indicated for treatment of hypocalcemia requiring prompt increase in blood plasma calcium levels 2
- Calcium chloride is specifically indicated for treating magnesium intoxication due to overdosage of magnesium sulfate 2
- Calcium administration may be considered during cardiac arrest associated with hypermagnesemia (Class IIb, LOE C) 1
Pitfalls in Calcium Administration
- Calcium chloride may be preferable to calcium gluconate in the setting of abnormal liver function, where decreased citrate metabolism results in slower release of ionized calcium 1
- Acidic solutions of calcium packaged in glass vials, such as calcium gluconate, are contaminated with aluminum and should not be used in parenteral nutrition (PN) 1
- Organic calcium salts are recommended for compounding of PN solutions to prevent precipitation 1
Magnesium Correction
Intravenous Magnesium Correction
- For severe hypomagnesemia or cardiac arrest associated with hypomagnesemia, IV magnesium sulfate 1-2 g bolus is recommended (Class I, LOE C) 1
- Magnesium sulfate injection is indicated for replacement therapy in magnesium deficiency, especially in acute hypomagnesemia accompanied by signs of tetany 3
- For parenteral nutrition, magnesium sulfate may be added to nutrient admixture to correct or prevent hypomagnesemia 3
Oral Magnesium Correction
- For mild hypomagnesemia, oral magnesium oxide at 12-24 mmol daily is recommended, with 12 mmol typically given at night 4
- Magnesium oxide is preferred for oral supplementation as it contains more elemental magnesium than other salts 4
- Organic magnesium salts (aspartate, citrate, lactate) have higher bioavailability than magnesium oxide and can be considered as alternatives 4
Monitoring and Considerations
- Target serum magnesium level should be within normal range (1.8-2.2 mEq/L) 4
- Magnesium may be provided using magnesium sulfate or magnesium chloride, but magnesium chloride increases the anion gap, potentially causing metabolic acidosis 1
- Most oral magnesium salts are poorly absorbed and may worsen diarrhea in patients with gastrointestinal disorders 4
Special Clinical Scenarios
Hypermagnesemia Management
- For hypermagnesemia causing cardiac arrest, administer calcium chloride (10%) 5-10 mL or calcium gluconate (10%) 15-30 mL IV over 2-5 minutes 1
- Calcium administration counteracts the effects of hypermagnesemia by antagonizing magnesium at the cellular level 2
Calcium-Magnesium Balance Considerations
- A calcium-to-magnesium ratio range of 1.70-2.60 (weight to weight) has been proposed as optimal 5
- In individuals with high calcium intakes, magnesium supplementation may be warranted to establish a more favorable dietary calcium-to-magnesium ratio 5
- When administering magnesium supplements, they should be given with meals to improve absorption and effectiveness 6
Parenteral Nutrition Considerations
- For compounding PN solutions, organic calcium and phosphorus salts are recommended to prevent precipitation 1
- Magnesium is usually administered as magnesium sulfate in PN with few compatibility issues 1
- The adequacy of calcium and phosphorus intakes in preterm infants can be adjusted until both start being excreted simultaneously with low urine concentrations (>1 mmol/L) 1