Compatibility of Magnesium with Lactated Ringer's Solution
Magnesium sulfate is physically compatible with Lactated Ringer's solution and can be safely administered together. 1
Evidence for Compatibility
The compatibility of magnesium sulfate with Lactated Ringer's (LR) solution is supported by research demonstrating:
- Storage stability tests performed on magnesium sulfate in LR showed no consistent decreases in measured elemental concentrations or gross signs of precipitation over a three-month period 1
- This stability was maintained when stored at room temperature in both glass bottles and polyvinyl chloride bags 1
Clinical Context for LR Use
Lactated Ringer's solution is commonly used in various clinical settings:
- The American Burn Association recommends balanced crystalloids such as LR for initial resuscitation in burn patients 2
- LR is preferred for emergency laparotomy patients as it causes fewer electrolyte derangements compared to 0.9% saline 3
- LR contains:
- 130 mEq/L sodium
- 109 mEq/L chloride
- 4 mEq/L potassium
- 3 mEq/L calcium
- 28 mEq/L lactate buffer 3
Important Considerations and Exceptions
While magnesium is compatible with LR, it's important to note:
- In a comprehensive Y-site compatibility study of 94 medications with LR, 8 drugs were found to be incompatible: ciprofloxacin, cyclosporine, diazepam, ketamine, lorazepam, nitroglycerin, phenytoin, and propofol 4
- These incompatible medications should not be administered with LR through the same line
Clinical Applications
When administering magnesium with LR:
- Monitor serum magnesium levels as appropriate for the clinical indication
- For patients requiring both magnesium supplementation and fluid resuscitation, LR can be used as the carrier solution
- In postoperative hypotension management where LR boluses are indicated, concurrent magnesium administration is safe 3
Practical Recommendations
- For Y-site administration, magnesium sulfate can be safely administered alongside LR without concerns for precipitation or chemical incompatibility
- For admixtures, magnesium sulfate remains stable in LR solution for extended periods (tested up to three months) 1
- When administering multiple medications, always check compatibility of all agents, not just magnesium
This compatibility information allows clinicians to confidently administer magnesium with LR when clinically indicated, without concerns about physical or chemical incompatibility.