Recommended PEG 3350 Dose for a 5-Year-Old Weighing 18 kg
For a 5-year-old child weighing 18 kg with functional constipation, start with approximately 14-16 grams of PEG 3350 daily (0.8 g/kg/day), dissolved in 4-6 ounces of liquid, and adjust the dose every 3 days to achieve 1-2 soft stools per day. 1, 2
Initial Dosing Strategy
- Begin with 0.8 g/kg/day, which translates to approximately 14.4 grams for an 18 kg child 2, 3
- This can be rounded to 14-16 grams (approximately one standard 17-gram packet) for practical administration 1
- Dissolve the powder in 4-6 ounces of any beverage once daily 1
Dose Titration Protocol
- Adjust the dose every 3 days based on stool frequency and consistency to reach the target of 1-2 soft stools per day 1, 2
- The effective maintenance dose typically ranges from 0.78-0.84 g/kg/day in pediatric patients, which would be 14-15 grams for this child 4, 2
- Some children may require doses as low as 0.27 g/kg/day or as high as 1.42 g/kg/day depending on individual response 2
Expected Response and Duration
- Greatest efficacy typically occurs in week 2 of treatment, with sustained effectiveness demonstrated over 6 months without loss of effect 1
- Success rates exceed 85-95% in children this age when properly dosed 3, 5
- Continue treatment for several months to allow bowel retraining and prevent relapse 3
Safety Considerations and Side Effects
- PEG 3350 is well-tolerated with minimal adverse effects in all pediatric age groups 1, 6
- The most common side effect is transient diarrhea, which resolves by reducing the dose 4, 3
- Minor adverse events may include bloating, abdominal discomfort, and increased gas, but these are generally mild 7, 5
- Ensure adequate hydration throughout the day, as PEG is an osmotic laxative that works by drawing water into the colon 1
Common Pitfalls to Avoid
- Do not underdose: Starting too low (less than 0.5 g/kg/day) may result in inadequate response and treatment failure 2
- Do not stop too early: Premature discontinuation before bowel retraining is complete leads to relapse 3
- Monitor for over-response: If watery diarrhea develops, reduce the dose rather than stopping treatment entirely 4, 3
- In children predisposed to electrolyte imbalances, consider monitoring serum electrolytes, though this is rarely necessary in otherwise healthy children 6