From the Guidelines
Magnesium supplements, specifically magnesium oxide (MgO), are a recommended treatment option for chronic idiopathic constipation, as they have been shown to increase the number of complete spontaneous bowel movements (CSBMs) per week and improve quality-of-life scores. According to the American Gastroenterological Association-American College of Gastroenterology clinical practice guideline 1, MgO may increase the number of CSBMs per week (MD 4.29,95% CI 2.93–5.65) and complete spontaneous bowel movements (SBMs) per week (MD 3.59,95% CI 2.64–4.54). The guideline also suggests that participants treated with MgO achieved a higher treatment response compared with placebo (RR 3.93,95% CI 2.04–7.56) 1.
Some key points to consider when using magnesium supplements for constipation include:
- The typical dose of MgO used in clinical trials is 1.5 g/d, but lower doses of 500 mg/d to 1 g/d are often used in clinical practice 1
- MgO is available over-the-counter and is a low-cost option, making it an attractive first-line treatment for chronic idiopathic constipation 1
- Magnesium supplements should be avoided in individuals with significant renal impairment (creatinine clearance <20 mg/dL) due to the risk of hypermagnesemia 1
- The panel suggests starting at a lower dose, which may be increased if necessary, and avoiding use in patients with renal insufficiency 1
Overall, magnesium supplements, particularly MgO, are a viable treatment option for chronic idiopathic constipation, with benefits including increased bowel movements and improved quality-of-life scores, as supported by the highest quality and most recent study 1.
From the FDA Drug Label
Warnings Ask a doctor before use if you have kidney disease a magnesium-restricted diet stomach pain, nausea, or vomiting a sudden change in bowel habits that lasts over 14 days Ask a doctor or pharmacist before use If you aretaking a prescription drug. This product may interact with certain prescription drugs. Stop use and ask a doctor if you have rectal bleeding or no bowel movement after using this product. If pregnant or breast-feeding,ask a health professional before use.
- Magnesium supplements can interact with certain prescription drugs, and individuals with kidney disease or a magnesium-restricted diet should ask a doctor before use 2.
- It is recommended to ask a health professional before use if pregnant or breast-feeding 2.
- The active ingredient in one of the magnesium supplements is Magnesium hydroxide 400 mg per 5 mL 2.
- Individuals should stop use and ask a doctor if they have rectal bleeding or no bowel movement after using this product 2.
From the Research
Magnesium Supplements and Chronic Kidney Disease
- Magnesium is an essential cation for multiple processes in the body, and its balance is regulated by the kidneys 3.
- In patients with chronic kidney disease (CKD), renal regulatory mechanisms may be insufficient to balance intestinal magnesium absorption, leading to changes in serum magnesium levels 3.
- Low magnesium levels are associated with several complications, including hypertension, vascular calcification, and increased risk of cardiovascular disease and non-CVD mortality 3, 4.
- Certain drugs used in CKD patients can decrease gastrointestinal absorption and kidney reclamation of magnesium, potentially causing hypomagnesemia, while other magnesium-containing drugs can induce hypermagnesemia 5.
Magnesium Administration in CKD
- Magnesium administration, mainly through oral supplements or increasing dialysate magnesium, has been shown to improve parameters of vascular function and calcification and mineral metabolism in people with CKD 6.
- Several oral magnesium formulations are available, with varying daily dosages of elemental magnesium, causing considerable heterogeneity in study results 6.
- Current clinical research suggests that magnesium administration in people with CKD is safe, without concerns for severe hypermagnesemia or negative interference with bone metabolism 6, 4.
- Randomized trials have shown the efficacy of oral magnesium oxide in retarding the progression of coronary artery calcification among non-dialysis CKD patients, and magnesium may provide better cardiovascular prognosis 4.