MiraLAX (Polyethylene Glycol) Dosing for Pediatric Patients
For pediatric patients with constipation, MiraLAX (polyethylene glycol 3350) should be dosed at 0.5-1.5 g/kg/day, with a typical effective dose of 0.7 g/kg/day, not to exceed 17 grams per day. 1
Age-Based Dosing Recommendations
Children Under 16 Years
- According to the FDA label, children under 16 years of age should only use MiraLAX under physician guidance 2
- Research supports the following dosing regimen:
- Initial dose: 0.5-0.7 g/kg/day
- Maintenance dose: 0.5-1.5 g/kg/day
- Average effective dose: 0.63 g/kg/day 1
- Maximum daily dose: 17 grams (equivalent to adult dose)
Children 17 Years and Older
- Use adult dosing: 17 grams once daily
- Fill cap to white line (17 g) and mix with 4-8 ounces of beverage 2
Administration Guidelines
- Mix prescribed dose in 4-8 ounces of any beverage (cold, hot, or room temperature)
- Ensure powder is completely dissolved before drinking
- Can be administered once daily or divided into two doses
- For severe constipation, a two-day preparation regimen of 1.5 g/kg divided twice per day has been shown to be effective 3
- Duration: Do not use for more than 7 days without physician supervision 2
Clinical Considerations
- MiraLAX is generally well-tolerated in pediatric patients
- The most common adverse effect is diarrhea (reported in approximately 25% of patients) 1
- No significant electrolyte disturbances have been reported in studies of pediatric patients 4
- One-day bowel preparation with MiraLAX has been shown to be as effective and safe as three-day preparation for colonoscopy in children 4
Practical Dosing Example
For a 20 kg child:
- Starting dose: 0.7 g/kg/day = 14 grams daily
- Can be administered as a single dose or divided into two doses of 7 grams each
- Mix each dose in 4-8 ounces of preferred beverage
Special Considerations
- For children with dysfunctional elimination (including daytime wetting), treatment of constipation with MiraLAX has been shown to improve voiding symptoms 1
- For colonoscopy preparation, a higher dose of 1.5 g/kg divided twice daily for 1-2 days may be used 3, 4
- Monitor for adequate response and adjust dosing as needed
MiraLAX's efficacy, compliance, and lack of significant side effects make it an ideal treatment for constipation in children, particularly as an adjunct to education and behavioral training 5.