What is the recommended dose of Miralax (polyethylene glycol) for pediatric patients with constipation?

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Last updated: June 2, 2025View editorial policy

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From the Research

The recommended dose of Miralax (polyethylene glycol 3350) for pediatric constipation is typically 0.5-1.5 g/kg/day, with a maximum daily dose of 17 grams, as supported by the most recent and highest quality study 1.

Key Considerations

  • For most children, starting with 17 grams (one capful or packet) mixed in 8 ounces of liquid once daily is appropriate for those over 4 years of age, while younger children may start with half this dose (8.5 grams) 2.
  • The medication should be dissolved completely in water, juice, or another beverage and can be administered for 2-6 months for chronic constipation.
  • Dosing can be adjusted based on response, with the goal of achieving soft, formed bowel movements.
  • Miralax works by drawing water into the intestines, softening stool and making it easier to pass, as explained in a study on its effectiveness 3.

Administration and Monitoring

  • Parents should monitor for adequate hydration while using Miralax, as it can occasionally cause loose stools if dosed too high.
  • If constipation persists despite appropriate dosing for several days, or if there are concerns about abdominal pain, vomiting, or blood in the stool, medical attention should be sought.
  • It is essential to follow the recommended dosage and administration guidelines to ensure the safe and effective use of Miralax in pediatric patients, as highlighted in a review of its use in functional constipation and fecal impaction 3.

References

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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