What is the dosing of magnesium citrate for treatment of constipation?

From the Guidelines

The recommended dose of magnesium citrate for constipation treatment is not explicitly stated in the provided guideline, but based on the available information, magnesium oxide is suggested for use, and by extension, magnesium citrate can be considered, with a typical adult dose ranging from 150-300 mg per day, taken orally, and the dose may be increased if necessary, while avoiding use in patients with renal insufficiency due to the risk of hypermagnesemia 1.

Key Considerations for Magnesium Citrate Use

• The provided guideline does not directly address magnesium citrate dosing but suggests the use of magnesium oxide for constipation treatment, implying that magnesium citrate could be an alternative option, given its similar mechanism of action as an osmotic laxative.
• When using magnesium citrate, it is essential to start with a lower dose, which can be increased as needed, to minimize side effects such as abdominal distension, loose stool, flatulence, and nausea.
• Patients with renal insufficiency should avoid using magnesium citrate due to the risk of hypermagnesemia, emphasizing the need for careful patient selection and monitoring.
• The guideline recommends the use of fiber supplements, particularly psyllium, as first-line therapy for chronic idiopathic constipation (CIC), with osmotic laxatives like polyethylene glycol (PEG) being recommended for use compared to management without PEG, indicating that magnesium citrate could be considered as part of a broader treatment strategy for constipation.

Practical Advice for Magnesium Citrate Administration

• Take magnesium citrate on an empty stomach to enhance absorption.
• Drink plenty of fluids throughout the day to help soften stool and stimulate bowel movements.
• Expect bowel movements within a few hours after dosing, typically ranging from 30 minutes to 6 hours.
• Regular use of magnesium citrate should be avoided without medical supervision to prevent dependence and potential side effects.
• If constipation persists or recurs frequently, consult a healthcare provider to rule out underlying conditions that may require alternative treatments.

From the FDA Drug Label

Directions shake well before using drink a full glass (8 ounces) of liquid with each dose may be taken as a single daily dose or in divided doses adults and children 12 years of age and over - 6.5 to 10 fl oz maximum 10 fl oz in 24 hours children 6 to under 12 years of age - 3 to 7 fl oz maximum 7 fl oz in 24 hours children 2 to under 6 years of age - 2 to 3 fl oz in 24 hours maximum 3 fl oz in 24 hours children under 2 years of age - ask a doctor

The dosing of magnesium citrate for treatment of constipation is as follows:

• Adults and children 12 years of age and over: 6.5 to 10 fl oz, with a maximum of 10 fl oz in 24 hours
• Children 6 to under 12 years of age: 3 to 7 fl oz, with a maximum of 7 fl oz in 24 hours
• Children 2 to under 6 years of age: 2 to 3 fl oz in 24 hours, with a maximum of 3 fl oz in 24 hours
• Children under 2 years of age: should ask a doctor for dosing instructions 2

From the Research

Dosing of Magnesium Citrate for Constipation

• The dosing of magnesium citrate for the treatment of constipation is not explicitly stated in the provided studies 3, 4, 5, 6, 7.
• However, study 4 mentions that oral magnesium citrate 17.7 or 35.4 g was used as a comparator to sodium picosulfate/magnesium citrate in adult patients undergoing a double-contrast barium enema procedure.
• Study 6 compared the bioavailability of different magnesium preparations, including magnesium citrate, at a daily dose of 300 mg of elemental magnesium.
• Study 5 used a magnesium sulfate-rich natural mineral water, which is different from magnesium citrate, but may provide some insight into the use of magnesium for constipation.

Magnesium Citrate Bioavailability

• Study 6 found that magnesium citrate had superior bioavailability compared to other magnesium preparations, including magnesium oxide and amino-acid chelate.
• The study used a daily dose of 300 mg of elemental magnesium and found that magnesium citrate led to the greatest mean serum magnesium concentration and the greatest mean salivary magnesium concentration.

Clinical Use of Magnesium Citrate

• Study 4 used sodium picosulfate/magnesium citrate, which contains magnesium citrate as an osmotic laxative, to prepare the colon for diagnostic procedures.
• Study 7 compared the efficacy and safety of sodium picosulfate/magnesium citrate with ascorbic acid-enriched polyethylene glycol solution plus bisacodyl for bowel preparation in a physically disabled outpatient population.
• While these studies provide some information on the use of magnesium citrate for constipation, they do not provide a clear recommendation for the dosing of magnesium citrate for this indication 3, 4, 5, 6, 7.