What is the recommended dosing frequency for Miralax (polyethylene glycol 3350)?

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Last updated: September 22, 2025View editorial policy

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Recommended Dosing Frequency for Miralax (Polyethylene Glycol 3350)

For adults and children 17 years or older, Miralax (polyethylene glycol 3350) should be taken once daily at a dose of 17 grams dissolved in 4-8 ounces of beverage. 1, 2

Standard Dosing Protocol

  • Initial dose: 17 grams (one capful or one packet) once daily
  • Administration: Dissolve completely in 4-8 ounces of any beverage (cold, hot, or room temperature)
  • Duration: FDA labeling indicates not to use for more than 7 days without medical supervision 2
  • Timing: Can be taken at any time of day, with no specific timing requirements

Efficacy and Safety

Polyethylene glycol 3350 (Miralax) has been strongly recommended by the American Gastroenterological Association for the management of chronic constipation 1. Clinical evidence shows:

  • Increases complete and spontaneous bowel movements by approximately 2.9 per week compared to placebo 1
  • 83.3% of patients achieve more than 3 stools per week after 14 days of treatment 3
  • Long-term safety has been established for up to 12 months of continuous use 4
  • No significant changes in electrolytes or other laboratory values with standard dosing 4

Important Administration Guidelines

  • Ensure the powder is fully dissolved before drinking
  • Do not combine with starch-based thickeners used for difficult swallowing
  • Do not consume if there are any undissolved clumps 2

Special Considerations

For Severe Constipation

  • In cases of severe constipation or fecal impaction, higher doses (up to 68 grams) may be considered for short-term use under medical supervision 5
  • A 68-gram dose has been shown to provide effective relief within 24 hours in constipated adults 5

Duration of Effect

  • Be aware that constipation often returns after discontinuation of treatment
  • Studies show 61.7% of patients require additional constipation treatment within 30 days after stopping PEG 3350 3

Common Side Effects

  • Abdominal distension
  • Flatulence
  • Nausea
  • Abdominal discomfort 1
  • Diarrhea (with higher doses) 6

Precautions

  • Children 16 years of age or under should only use Miralax under physician supervision 2
  • Adequate hydration is essential during treatment to minimize side effects 1
  • Patients with severe cardiac or renal disease should use with caution 7

Miralax provides safe and effective relief of constipation when used as directed, with high patient satisfaction rates and good tolerability compared to other laxative options.

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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