What is the use of magnesium citrate?

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From the Guidelines

Magnesium citrate is primarily used as a laxative to relieve occasional constipation and for bowel preparation before colonoscopies or certain surgical procedures. It typically works within 30 minutes to 3 hours by drawing water into the intestines, which helps soften stool and stimulate bowel movements. The standard adult dose is usually 195-300 mL taken with a full glass of water, preferably on an empty stomach. Children's dosages vary by age and should be determined by a healthcare provider. Beyond constipation relief, magnesium citrate is sometimes used for bowel preparation before colonoscopies or certain surgical procedures, requiring complete emptying of the intestines. It may also be prescribed as a magnesium supplement for those with deficiencies, though other magnesium forms are often preferred for this purpose. People with kidney disease, heart conditions, intestinal blockages, or those taking certain medications should avoid magnesium citrate. Side effects can include abdominal cramping, nausea, and diarrhea. The laxative effect occurs because magnesium ions attract water molecules in the digestive tract through osmosis, while the citrate component enhances this effect by stimulating intestinal fluid secretion. According to a study published in 2023 1, the American Gastroenterological Association suggests the use of MgO over management without MgO for adults with chronic idiopathic constipation, although the certainty of evidence is very low. However, it's essential to note that magnesium citrate is not the same as MgO, and its efficacy and safety for constipation relief may differ, as mentioned in another study from 2023 1. In the context of bowel preparation, a study from 2014 1 found that adding magnesium citrate to a bowel preparation regimen improved the quality of bowel preparation in diabetic patients undergoing colonoscopy. Overall, magnesium citrate can be a useful agent for constipation relief and bowel preparation, but its use should be guided by a healthcare provider, especially in patients with underlying medical conditions or taking certain medications. Some key points to consider when using magnesium citrate include:

  • Dosage: The standard adult dose is usually 195-300 mL taken with a full glass of water.
  • Contraindications: People with kidney disease, heart conditions, intestinal blockages, or those taking certain medications should avoid magnesium citrate.
  • Side effects: Abdominal cramping, nausea, and diarrhea are possible side effects.
  • Efficacy: Magnesium citrate can be effective for constipation relief and bowel preparation, but its efficacy may vary depending on the individual and the specific condition being treated. It's crucial to weigh the benefits and risks of using magnesium citrate, considering the latest evidence and individual patient factors, to optimize outcomes in terms of morbidity, mortality, and quality of life.

From the FDA Drug Label

Use for relief of occasional constipation (irregularity). Generally produces bowel movement in 1/2 to 6 hours Magnesium citrate is used for the relief of occasional constipation. It is intended to produce a bowel movement within a specific time frame, typically between 1/2 to 6 hours 2.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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