From the Guidelines
Magnesium citrate is a recommended treatment for constipation and bowel preparation in the Emergency Department, with a typical adult dose of 10 ounces (300 mL) of the standard solution, as it has been shown to be effective and well-tolerated in recent studies, such as 1. The use of magnesium citrate in the ED is supported by its mechanism of action as an osmotic laxative, which draws water into the intestinal lumen and stimulates intestinal motility.
- Key considerations for its use include:
- Contraindications: renal insufficiency, heart block, myocardial damage, and bowel obstruction, as noted in 1 and 1
- Caution in elderly patients and those with electrolyte abnormalities, due to the risk of hypermagnesemia, as highlighted in 1
- Side effects: abdominal cramping, nausea, and diarrhea, which are generally mild and self-limiting
- Pediatric dosing: 2-4 mL/kg for children over 2 years old, not to exceed adult dosing, although this may vary depending on the specific clinical context The most recent and highest quality study, 1, provides guidance on the use of magnesium citrate in combination with other agents, such as sodium picosulfate, for bowel preparation, and notes that it is approved by the FDA for this indication.
- Important factors to consider when using magnesium citrate in the ED include:
- Patient hydration status, as magnesium citrate can cause dehydration if not balanced with adequate fluid intake
- Electrolyte monitoring, particularly in patients with renal insufficiency or other electrolyte disturbances
- Dose adjustment and monitoring for efficacy and side effects, as needed, to ensure optimal patient outcomes.
From the Research
Magnesium Citrate in Emergency Department (ED)
- Magnesium citrate is used to treat constipation in the ED, but it can cause hypermagnesemia, a rare phenomenon that can lead to paralysis and respiratory failure 2.
- A case study reported a 73-year-old male patient who presented to the ED with diffuse abdominal pain and received magnesium citrate for constipation, which led to hypermagnesemia and subsequent respiratory failure 2.
- Another case study reported a 63-year-old woman who presented to the ED with progressive dyspnea, constipation, and generalized weakness after using magnesium citrate and milk of magnesia, which led to hypermagnesemic asystolic cardiac arrest 3.
- The use of magnesium in the ED has been advocated for various conditions, including severe asthma, eclampsia, and torsade de pointes, but its routine use in other emergencies is not supported by evidence 4.
- The evaluation and management of constipation in the ED is limited by a lack of evidence, and many treatments have not been studied in modern, rigorous, controlled trials 5.
- Hypomagnesemia, on the other hand, has been associated with various disorders, including seizures, malignant ventricular dysrhythmias, and sudden death, and can be treated with magnesium supplementation 6.