Is Miralax Safe for a 1-Year-Old?
Yes, Miralax (polyethylene glycol 3350) is safe and effective for treating constipation in 1-year-old children, though the FDA-approved labeling recommends asking a doctor for children 16 years and under.
FDA Labeling and Age Considerations
The official FDA labeling for polyethylene glycol 3350 states that for children 16 years of age or under, caregivers should "ask a doctor" before use 1. However, this conservative labeling does not reflect the substantial clinical evidence supporting its safety in younger children, including infants.
Clinical Evidence in Young Children
Research demonstrates that polyethylene glycol is both safe and effective in children under 18 months of age, including 1-year-olds:
- A study of 28 patients younger than 18 months (including 16 children aged 12-17 months, which encompasses 1-year-olds) found that PEG 3350 relieved constipation in 97.6% of patients 2
- The mean effective maintenance dose was 0.78 g/kg/day (range 0.26-1.26 g/kg/day) 2
- Mean duration of therapy was 6.2 months (range 3 weeks to 21 months), demonstrating safety with prolonged use 2
- Adverse effects were minimal: one infant experienced increased gas and four had transient diarrhea that resolved with dose adjustment 2
Long-Term Safety Profile
A 52-week randomized controlled trial in children aged 0.5 to 16 years confirmed long-term safety 3:
- For children 0-2 years, daily sachet use ranged from 0.4 to 2.3 sachets
- No drug-related serious adverse events occurred during the year-long study 3
- Treatment success (≥3 bowel movements per week with <1 episode of fecal incontinence) was achieved in approximately 50% of children 3
Practical Dosing Recommendations
For a 1-year-old child with constipation:
- Start with approximately 0.78 g/kg/day as a maintenance dose 2
- Dissolve the powder completely in 4-8 ounces of any beverage (cold, hot, or room temperature) 1
- Adjust dose based on response—if diarrhea occurs, reduce the dose 2
- Do not combine with starch-based thickeners 1
Important Caveats
- While the FDA label states "do not use more than 7 days" for over-the-counter use 1, clinical studies demonstrate safety for much longer durations under medical supervision 2, 3
- Ensure the powder is fully dissolved before administration and do not give if clumps remain 1
- Monitor for transient diarrhea, which can be managed by dose reduction 2