What is the appropriate PEG 3350 (Restoralax) dose for a child weighing 12.2 kg?

PEG 3350 Dosing for a 12.2 kg Child

For a child weighing 12.2 kg, start with approximately 5 grams (1.5 teaspoons) of PEG 3350 (Restoralax) once daily for maintenance therapy of functional constipation, which can be titrated up to 0.8 g/kg/day (approximately 10 grams or 3 teaspoons) based on response.

Dosing Algorithm

Maintenance Therapy (Most Common Scenario)

• Starting dose: 0.4 g/kg/day = 4.9 grams (approximately 1.5 teaspoons) once daily 1

  • This dose showed optimal efficacy with minimal side effects in pediatric trials
  • Can be rounded to 5 grams for practical measurement

• Dose titration: If inadequate response after 1-2 weeks, increase to 0.6-0.8 g/kg/day (7-10 grams daily) 1

  • Maximum studied maintenance dose: 0.8 g/kg/day = 9.8 grams (approximately 3 teaspoons)

Fecal Disimpaction (If Present)

• Disimpaction dose: 1.0-1.5 g/kg/day = 12-18 grams daily for 3 days 2
  • Higher doses (1.0-1.5 g/kg/day) achieved 95% disimpaction success vs 55% with lower doses
  • After disimpaction, transition to maintenance dosing

Practical Measurement Considerations

Using household measuring devices 3:

• 1 leveled teaspoon ≈ 3.3 grams of PEG 3350
• 1 leveled tablespoon ≈ 10 grams of PEG 3350
• Always level the measuring device to improve consistency and reduce variability

For this 12.2 kg child:

• Maintenance: 1.5 teaspoons (5 grams) once daily
• Disimpaction (if needed): 3-4 teaspoons (12-15 grams) once daily for 3 days

Evidence Supporting This Approach

The dosing recommendation is based on high-quality pediatric research demonstrating that 0.4 g/kg/day is the optimal starting dose for maintenance therapy 1. This multicenter, double-blind, placebo-controlled trial showed 74% treatment success (≥3 bowel movements/week) with 0.4 g/kg/day compared to 42% with placebo, with significantly improved stool consistency and less straining. The 0.8 g/kg/day dose showed similar efficacy but increased abdominal pain and fecal incontinence 1.

For children under 24 months, systematic review data supports dosing ranges of 0.45-1.1 g/kg/day for PEG 3350, with no significant safety concerns 4. A recent comparative trial confirmed PEG efficacy and safety in children as young as 6 months 5.

Safety Profile

• Adverse effects are generally mild and transient: bloating (18%), diarrhea (13%), nausea (5%), vomiting (5%), cramping (5%) 2
• No clinically significant electrolyte disturbances have been documented in pediatric studies 2
• Higher doses (0.8 g/kg/day) increase risk of abdominal discomfort 1

Common Pitfalls to Avoid

1. Don't start too high: Beginning with adult doses (17 grams) in small children causes unnecessary side effects
2. Don't use unleveled measurements: This creates 10-15% dose variability 3
3. Don't forget disimpaction: If fecal impaction is present, maintenance doses alone will fail—use higher disimpaction doses first 2
4. Don't underdose chronically: If 0.4 g/kg/day fails after 2 weeks, titrate up rather than switching agents 1

Duration of Therapy

Long-term use is appropriate and safe. Studies demonstrate efficacy and safety for up to 12 months in pediatric patients 5. Continue treatment until regular bowel patterns are established, typically several months minimum.