What is the recommended dose and frequency of magnesium citrate (Mg citrate)?

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Last updated: May 8, 2025View editorial policy

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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 recommended dose and frequency of magnesium citrate are as follows:

  • 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, maximum 3 fl oz in 24 hours
  • Children under 2 years of age: ask a doctor 1

From the Research

Magnesium citrate should be taken as a single dose of 300 mL for adults, as part of a bowel preparation regimen, with a recommended 4-L fluid intake, as evidenced by the noninferiority of sodium picosulfate/magnesium citrate compared to ascorbic acid-enriched polyethylene glycol solution plus bisacodyl in achieving adequate bowel preparation 2. When using magnesium citrate for bowel preparation, it is essential to follow the recommended dosage and fluid intake to ensure effective bowel cleansing and minimize the risk of dehydration.

  • The dose for adults is typically 300 mL, which is part of the sodium picosulfate/magnesium citrate preparation.
  • Patients should be advised to drink plenty of water, with a recommended 4-L fluid intake, to help prevent dehydration and ensure the medication works effectively.
  • The medication usually works within 30 minutes to 6 hours after consumption, and its efficacy in achieving adequate bowel preparation has been demonstrated in studies, such as the PICO-MOVI study 2.
  • It is crucial to note that magnesium citrate should not be used regularly for constipation, as it can lead to dependence and electrolyte imbalances.
  • Additionally, individuals with kidney disease, heart conditions, or those taking certain medications should consult a healthcare provider before using magnesium citrate, as it can interact with medications and affect electrolyte balance.

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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