From the Guidelines
Magnesium oxide (MgO) at a dose of 1.5 g/d is recommended for the management of chronic idiopathic constipation, as it has been shown to be effective in creating an osmotic gradient that leads to net secretion of water and electrolytes, thereby exerting a beneficial effect on constipation-related symptoms 1. When considering the use of magnesium for constipation, it is essential to note that lower doses of 500 mg/d to 1 g/d are often used in clinical practice, although these doses have not been studied in randomized controlled trials (RCTs) 1. Key points to consider when using magnesium for constipation include:
- MgO is the only formulation of magnesium that has been evaluated in RCTs, and its bioavailability and clinical efficacy are unknown for other formulations such as citrate, glycinate, lactate, malate, and sulfate 1
- The available data suggest no increased reports of diarrhea with MgO compared with placebo 1
- Systemic regulation of magnesium levels is maintained by renal excretion, and hypermagnesemia is more likely to occur in individuals with significant renal impairment, making it essential to avoid magnesium supplements in those with a creatinine clearance of <20 mg/dL 1
- Magnesium supplements should be taken with plenty of water, and the dose can be split throughout the day to improve tolerance
- Individuals with kidney disease or those on certain medications should consult a doctor before taking magnesium supplements 1
From the FDA Drug Label
Active ingredient per 30mL (1 Unit Dose) Magnesium hydroxide 2,400 mg The recommended dose of magnesium hydroxide for constipation is 2,400 mg per 30mL (1 Unit Dose) 2.
From the Research
Magnesium Dose for Constipation
- The study 3 discusses various treatment options for chronic constipation, including nonpharmacologic and pharmacologic modalities.
- It mentions magnesium hydroxide as one of the traditional pharmacologic agents used to treat constipation, but notes that its use is not supported by strong clinical evidence.
- The study does not provide a specific dose of magnesium for constipation, focusing instead on the efficacy and safety of various therapies for chronic constipation.
- Other agents mentioned in the study, such as psyllium, polyethylene glycol, and lactulose, are noted to have some benefit in treating constipation, but the optimal dose of magnesium is not discussed.
- The lack of strong clinical evidence supporting the use of magnesium hydroxide for constipation suggests that more research is needed to determine its effectiveness and optimal dosage.