Miralax Dosing for Children
For children 17 years and older, the FDA-approved dose is 17 grams (one packet or capful) dissolved in 4-8 ounces of beverage once daily for up to 7 days, while children 16 years and under require physician consultation before use. 1
FDA-Approved Dosing by Age
Children 16 Years and Under
- The FDA label explicitly states to "ask a doctor" before administering Miralax to children 16 years of age or under 1
- This reflects that Miralax (polyethylene glycol 3350 without electrolytes) lacks FDA approval for pediatric use in this age group 1
Adolescents 17 Years and Older
- Dose: 17 grams once daily 1
- Mix one packet or capful in 4-8 ounces of any beverage (cold, hot, or room temperature) 1
- Ensure powder is fully dissolved before drinking; do not drink if clumps remain 1
- Maximum duration: 7 days without physician supervision 1
Evidence-Based Pediatric Dosing (Off-Label)
While not FDA-approved for children under 17, substantial research supports off-label use:
Infants Under 18 Months
- Mean effective maintenance dose: 0.78 g/kg/day (range 0.26-1.26 g/kg/day) 2
- A 2004 study demonstrated 97.6% efficacy in relieving constipation in 28 infants 2
- Safety profile similar to older children, with only transient diarrhea requiring dose adjustment in some cases 2
Children 18 Months and Older
- Typical dosing range: 0.4-3.8 sachets (approximately 6.8-64.6 grams) daily, depending on age and response 3
- Age-specific ranges from a 2018 randomized controlled trial:
Important Safety Considerations
Administration Guidelines
- Do not combine with starch-based thickeners used for swallowing difficulties 1
- Ensure complete dissolution before consumption 1
- Can be mixed in any temperature beverage for palatability 1
When to Seek Medical Guidance
- All children 16 years and under require physician consultation before initiating therapy 1
- Duration exceeding 7 days requires medical supervision 1
- Dose adjustments should be made based on clinical response, particularly if diarrhea develops 2
Clinical Efficacy Notes
Long-term use (up to 52 weeks) has been studied in children, with treatment success (≥3 bowel movements per week with <1 fecal incontinence episode) achieved in approximately 45-50% of patients 3. The safety profile over this extended period showed no serious drug-related adverse events 3.