From the Guidelines
Magnesium citrate solution should be avoided in people with kidney disease, especially those with severe renal impairment, due to the risk of hypermagnesemia and magnesium toxicity. Patients with impaired kidney function should consult their healthcare provider before using magnesium citrate as a laxative or supplement. The kidneys are responsible for eliminating excess magnesium from the body, and when kidney function is compromised, magnesium can accumulate to dangerous levels in the bloodstream, potentially leading to magnesium toxicity 1. Symptoms of magnesium toxicity include low blood pressure, confusion, irregular heartbeat, muscle weakness, difficulty breathing, and in severe cases, cardiac arrest.
For patients with mild kidney impairment who need a laxative, healthcare providers might recommend reduced dosages (typically half the standard dose of 10 oz or less) or alternative laxatives that don't contain magnesium, such as polyethylene glycol (MiraLAX), bisacodyl, or docusate sodium. According to a recent study, sodium picosulfate þ magnesium citrate is contraindicated in patients with congestive heart failure, hypermagnesemia, and severe renal impairment because of its hyperosmolar nature 1.
Key considerations for patients with kidney disease include:
- Avoiding magnesium-containing products altogether in patients with moderate to severe kidney disease (stages 3-5)
- Regular blood tests to monitor magnesium levels in kidney disease patients who must use magnesium-containing products
- Considering alternative laxatives that don't contain magnesium for patients with mild kidney impairment
- Being aware of the potential risks of hypermagnesemia and magnesium toxicity in patients with kidney disease, as highlighted in recent guidelines 2, 3.
From the FDA Drug Label
Warnings kidney disease a magnesium restricted diet abdorominal pain, nausea, or vomiting noticed a sudden change in bowel habits that persists over a period of 2 weeks already used a laxative for a period longer than 1 week The use of magnesium citrate solution is cautioned in patients with kidney disease due to the risk of magnesium accumulation.
- Patients with kidney disease should be on a magnesium restricted diet. 4
From the Research
Magnesium Citrate Solution and Kidney Disease
- Magnesium homeostasis depends on the balance between gastrointestinal absorption and kidney excretion 5.
- In patients with chronic kidney disease (CKD), certain drugs can decrease gastrointestinal ingestion and kidney reclamation, potentially causing hypomagnesemia, while other magnesium-containing drugs can induce hypermagnesemia 5.
- The kidney plays a major role in regulating magnesium balance, and in CKD, renal regulatory mechanisms may be insufficient to balance intestinal magnesium absorption 6.
- Patients with end-stage renal disease on dialysis are largely dependent on the dialysate magnesium concentration for maintaining serum magnesium and magnesium homeostasis 6.
Magnesium Complications in CKD
- Low magnesium is associated with several complications, including hypertension, vascular calcification, and an increased risk for both cardiovascular disease and non-CVD mortality 6.
- Severe hypermagnesemia can cause cardiac conduction defects, neuromuscular effects, and muscle weakness, while a slightly elevated magnesium has been suggested to be beneficial in patients with end-stage renal disease 6.
- Magnesium balance remains poorly understood in patients with end-stage kidney disease, and large randomized trials are needed to test the hypotheses that magnesium-based compounds can serve as effective phosphate binders and have protective cardiovascular effects 7.
Magnesium Intake and Hypermagnesemia
- Daily magnesium intake is the most important determinant of serum magnesium concentration in hemodialysis patients with CKD 8.
- Hypermagnesemia was observed in patients ingesting more than 281 mg of magnesium daily, and magnesium-containing phosphate binders can be considered in the therapy of hyperphosphatemia in hemodialysis patients without hypermagnesemia 8.
- Magnesium supplementation might have a favorable effect on vascular calcification, although evidence for this is very slight, and additional research is needed to investigate the role of magnesium in CKD patients 9.