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 label recommends asking a doctor for children 16 years and under before use. 1
FDA Labeling and Official Guidance
The FDA-approved labeling for polyethylene glycol 3350 (Miralax) states that for "children 16 years of age or under: ask a doctor" before use. 1 This conservative labeling reflects the over-the-counter status of the medication rather than safety concerns in this age group.
Evidence-Based Safety and Efficacy
Research demonstrates that polyethylene glycol is both safe and effective specifically in children under 18 months of age:
A prospective study of 28 infants younger than 18 months (including 3 infants aged 0-5 months, 9 aged 6-11 months, and 16 aged 12-17 months) showed that PEG 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) with a safety profile similar to older children. 2
Side effects were minimal and transient: one infant experienced increased gas and four had temporary diarrhea that resolved with dose adjustment. 2
Mean duration of therapy was 6.2 months (range 3 weeks to 21 months), demonstrating safety with prolonged use. 2
Recommended Dosing for 1-Year-Olds
For a 1-year-old child, start with approximately 0.8 g/kg/day and adjust based on response:
The typical 1-year-old weighs 9-11 kg, which translates to approximately 7-9 grams daily (roughly 0.4-0.5 of a standard 17g packet). 2
Titrate the dose based on stool consistency and frequency—increase if constipation persists, decrease if diarrhea develops. 2
Mix the powder completely in 4-8 ounces of any beverage (cold, hot, or room temperature) and ensure full dissolution before giving. 1
Important Clinical Considerations
Key safety points when prescribing for infants:
Do not use for more than 7 days without medical supervision, per FDA labeling. 1
Ensure the powder is fully dissolved—do not give if clumps remain. 1
Long-term studies show comparable safety to placebo with no serious adverse events in pediatric populations. 3
A 52-week randomized controlled trial in children aged 0.5 to 16 years demonstrated no drug-related serious adverse events with either PEG formulation. 4
Broader Context of PEG Safety
Multiple clinical trials totaling 1,949 patients (including seven pediatric studies) have established PEG 3350's safety profile across all age groups. 3 The American College of Gastroenterology Task Force gave PEG 3350 a grade A recommendation for improving stool frequency and consistency. 3
Common pitfall to avoid: Do not combine PEG with starch-based thickeners used for swallowing difficulties, as this may affect dissolution and efficacy. 1