From the Guidelines
Hypermagnesemia is primarily caused by impaired renal excretion of magnesium, most commonly in patients with advanced kidney disease or acute kidney injury, and can be exacerbated by excessive magnesium intake through medications or other factors. The most frequent causes of hypermagnesemia include:
- Excessive magnesium intake through medications such as magnesium-containing antacids, laxatives (like milk of magnesia), or magnesium-based cathartics used for bowel preparation
- Intravenous magnesium sulfate administration, particularly in preeclampsia treatment or for cardiac arrhythmias, as noted in the 2010 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care 1
- Endocrine disorders such as hypothyroidism, adrenal insufficiency, and hyperparathyroidism, which may contribute to hypermagnesemia
- Rhabdomyolysis, which can release intracellular magnesium into the bloodstream
- Lithium toxicity, which may impair renal magnesium handling
- Familial hypocalciuric hypercalcemia, a rare genetic cause The normal serum magnesium range is 1.7-2.4 mg/dL, with symptoms typically appearing when levels exceed 4-5 mg/dL, as discussed in various studies on electrolyte disorders, including those related to cardiovascular disease and kidney function 1. Hypermagnesemia is particularly dangerous in elderly patients and those with compromised kidney function, as the kidneys are the primary route for magnesium elimination. Careful monitoring of magnesium levels is essential when administering magnesium-containing medications to at-risk patients.
From the Research
Causes of Hypermagnesemia
- Excessive magnesium intake, often through magnesium-containing medications or supplements, can lead to hypermagnesemia, as seen in patients taking magnesium hydroxide for constipation 2, 3, 4.
- Reduced renal excretion, particularly in patients with impaired kidney function, can also cause hypermagnesemia, as the kidneys play a crucial role in regulating magnesium levels in the body 2, 5, 3, 6.
- Hypermagnesemia can occur in patients with normal kidney function, especially when taking magnesium-containing products, highlighting the importance of monitoring magnesium levels in these individuals 5, 4.
- Certain medical conditions, such as bowel disorders or intestinal obstruction, can increase the risk of hypermagnesemia, particularly when combined with magnesium intake 3, 4.
- The use of over-the-counter laxatives or antacids containing magnesium can lead to severe symptomatic hypermagnesemia, especially in the elderly or those with concomitant renal failure 3.