What is the maximum daily dose of Miralax (polyethylene glycol)?

Maximum Daily Dose of Miralax (Polyethylene Glycol)

According to current guidelines, there is no clear maximum dose of polyethylene glycol (Miralax) established for constipation management. 1

Standard Dosing Information

• The recommended initial dose of polyethylene glycol is 17 g daily (one capful or packet) mixed in 4-8 ounces of beverage 2
• Dosing should be titrated based on symptom response and side effects 1
• The FDA-approved labeling indicates that adults and children 17 years of age and older should use once a day, and not use for more than 7 days without medical consultation 2

Higher Dosing Considerations

• Clinical research has investigated higher doses of polyethylene glycol for specific situations:
  • A study examining overnight efficacy tested doses of 51g, 68g, and 85g as single doses, with 68g appearing most satisfactory for rapid relief of constipation 3
  • The 68g dose produced an average of 2.2 bowel movements in 24 hours compared to 0.5 for placebo 3
  • Even at the highest tested dose of 85g (which produced 4.2 bowel movements in 24 hours), no significant adverse effects were reported 3

Safety Considerations

• Polyethylene glycol is generally well-tolerated even at higher doses 3, 4
• Common side effects include:
  • Bloating, abdominal discomfort, and cramping 1
  • Diarrhea and flatulence may occur, particularly at higher doses 4
• No significant changes in laboratory values (electrolytes, calcium, glucose, BUN, creatinine, or serum osmolality) were observed even with doses up to 85g 3

Clinical Application

• For chronic idiopathic constipation, polyethylene glycol has shown durable response over 6 months 1
• For patients requiring more rapid relief, higher doses may be considered:
  • 68g appears to provide effective relief within 24 hours 3
  • The average time to first bowel movement with 68g was 14.8 hours versus 27.3 hours for placebo 3

Important Caveats

• Higher doses should be used with caution in elderly patients or those with comorbidities 4
• Ensure adequate hydration when using polyethylene glycol, especially at higher doses 1
• Do not combine with starch-based thickeners used for difficult swallowing 2
• Ensure the powder is fully dissolved before drinking 2

While the standard dose is 17g daily, clinical evidence suggests that doses up to 68g may be used safely for more rapid relief of constipation when needed, with no established absolute maximum daily dose in the current guidelines.