From the Guidelines
Magnesium supplementation is not indicated in patients with kidney failure on dialysis because these patients are already at high risk for hypermagnesemia (elevated magnesium levels). In renal failure, the kidneys lose their ability to excrete excess magnesium, which is the primary route of magnesium elimination from the body. Dialysis patients often receive magnesium in their dialysate fluid and may also consume magnesium-containing medications such as antacids, laxatives, or phosphate binders. Additionally, many over-the-counter supplements contain magnesium. The accumulation of magnesium in these patients can lead to serious complications including neuromuscular dysfunction, cardiac arrhythmias, hypotension, respiratory depression, and in severe cases, cardiac arrest. Symptoms of hypermagnesemia include weakness, lethargy, nausea, facial flushing, and loss of deep tendon reflexes.
According to the most recent study 1, electrolyte abnormalities are common in patients with acute or chronic kidney disease, and magnesium supplementation should be avoided to prevent hypermagnesemia. Instead, dialysis solutions containing potassium, phosphate, and magnesium should be used to prevent electrolyte disorders during kidney replacement therapy (KRT) 1. The use of dialysis and replacement fluids with increased magnesium concentration may be indicated to prevent KRT-related hypomagnesemia, but this should be done with caution and close monitoring of serum magnesium levels 1.
Key points to consider:
- Hypermagnesemia is a serious complication in dialysis patients
- Magnesium supplementation should be avoided in patients with kidney failure on dialysis
- Dialysis solutions containing potassium, phosphate, and magnesium should be used to prevent electrolyte disorders during KRT
- Close monitoring of serum magnesium levels is necessary to prevent hypomagnesemia and hypermagnesemia.
If magnesium supplementation is absolutely necessary for a specific clinical indication in a dialysis patient, it should be administered only under close medical supervision with frequent monitoring of serum magnesium levels, and the dialysate magnesium concentration may need to be adjusted accordingly 1.
From the Research
Magnesium in Kidney Failure Patients on Dialysis
- Magnesium is an essential cation for multiple processes in the body, and its balance is crucial for patients with kidney failure on dialysis 2, 3.
- The kidney plays a principal role in magnesium balance, and in patients with chronic renal failure, urinary magnesium excretion may be insufficient to balance intestinal magnesium absorption 2.
- In dialysis patients, dialysate magnesium concentration plays a critical role in maintaining magnesium homeostasis, and serum magnesium levels are largely dependent on the concentration of the ion in the dialysis solution 2, 4.
Potential Harmful Effects of Elevated Magnesium
- Elevated magnesium levels can have harmful effects, including altered nerve conduction velocity, increased pruritus, and alterations to osseous metabolism and parathyroid gland function 2.
- Hypermagnesemia may also retard vascular calcification, and severe hypermagnesemia can cause cardiac conduction defects, neuromuscular effects, and muscle weakness 2, 3, 5.
Importance of Magnesium Balance
- Maintaining magnesium balance is crucial for patients with kidney failure on dialysis, as both low and high magnesium levels can have adverse effects 3, 4.
- Low magnesium levels have been associated with impairment of myocardial contractility, intradialytic hemodynamic instability, and hypotension, as well as carotid intima-media thickness, a marker of atherosclerotic vascular disease 2, 3.
- Regular measurement of predialysis plasma magnesium and adjustment of dialysate magnesium concentration to maintain plasma magnesium concentration within the normal range is recommended 4.