Polyethylene Glycol (PEG) Dosing for Constipation in a 9-Year-Old Child
For a 9-year-old child with constipation, the recommended dose of Polyethylene Glycol (PEG) is 0.4-0.8 g/kg/day, which typically translates to 17 grams daily mixed with 8 oz of liquid. 1
Dosage Calculation and Administration
For a 9-year-old child (average weight approximately 28-30 kg):
- Starting dose: 0.4 g/kg/day = approximately 11-12 grams daily
- Maximum dose: 0.8 g/kg/day = approximately 22-24 grams daily
- Standard adult dose (17g) is often appropriate for most school-aged children 1
Administration instructions:
- Mix with 8 oz (240 mL) of water or clear liquid
- Can be given once daily or divided into two doses
- Best administered in the morning or after school
Evidence Supporting This Recommendation
PEG has been extensively studied in pediatric populations and is considered a first-line treatment for constipation in children:
- A multicenter, double-blinded, placebo-controlled trial found that 0.4 g/kg/day of PEG3350 provided optimal efficacy with minimal side effects 2
- At 0.4 g/kg/day, 74% of children achieved successful treatment (defined as ≥3 bowel movements in the second week of treatment) 2
- Higher doses (0.8 g/kg/day) showed similar efficacy but increased risk of abdominal pain and fecal incontinence 2
Advantages of PEG for Pediatric Constipation
- PEG works as an osmotic laxative that draws water into the intestinal lumen
- Faster onset and fewer flatulence issues compared to other laxatives 1
- Well-tolerated with minimal systemic absorption
- Can be used safely for extended periods if needed
- Tasteless and odorless, improving compliance in children 3
Treatment Duration and Monitoring
- Initial treatment period: 2-4 weeks to achieve regular bowel movements
- Maintenance therapy may be needed for several months in children with chronic constipation
- Monitor for:
- Stool frequency (target: daily soft bowel movement)
- Stool consistency (target: soft, formed stool)
- Resolution of abdominal pain or discomfort
- Side effects (primarily transient diarrhea, which can be managed by adjusting the dose)
Potential Side Effects
- Most common: transient diarrhea (resolves with dose adjustment) 4
- Less common: abdominal bloating, gas, nausea
- Serious side effects are rare when used as directed
When to Consider Dose Adjustment
- If inadequate response after 3-5 days: increase dose by 0.2 g/kg/day
- If excessive loose stools: decrease dose by 0.2 g/kg/day
- Once regular bowel habits are established, consider gradual dose reduction while maintaining soft, regular stools
PEG has proven superior to other laxatives like lactulose in pediatric studies, with better efficacy and tolerability 5. Its safety profile and effectiveness make it the optimal choice for managing constipation in a 9-year-old child.