What is the recommended laxative syrup for a 3-year-old child with constipation?

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Recommended Laxative Syrup for a 3-Year-Old with Constipation

Polyethylene glycol (PEG) 3350 without electrolytes is the first-line laxative of choice for a 3-year-old child with constipation, as it provides superior efficacy with fewer side effects compared to alternatives like lactulose. 1, 2

First-Line Treatment: PEG 3350

  • PEG 3350 is the preferred laxative for childhood constipation in this age group, demonstrating a 56% success rate compared to only 29% with lactulose in head-to-head trials 2
  • Dosing for a 3-year-old: Start with approximately 0.26 g/kg/day (typically 10 g/m²/day or roughly half a capful daily), which can be mixed with any liquid 2, 3
  • PEG 3350 significantly reduces side effects including abdominal pain, straining, and pain during defecation compared to lactulose, though some children may complain of bad taste 2
  • The medication is safe and effective for long-term use in pediatric populations over 6 months of age 4, 5

Alternative Option: Lactulose

  • Lactulose (6 g/sachet) can be used if PEG 3350 is unavailable or not tolerated, though it is less effective 2
  • Lactulose is authorized for infants before 6 months of age, making it safe for all pediatric age groups 4
  • Typical dosing: 1.3 g/kg/day divided twice daily (up to 20 g total) 3

Adjunctive Dietary Measures

  • Sorbitol-containing juices (prune, pear, or apple juice) can help increase stool frequency and water content in mild constipation 6, 1, 4
  • Recommended juice intake: 2-4 oz daily for mild, recent-onset constipation 1
  • Ensure adequate hydration to optimize laxative effectiveness 1

Critical Medications to AVOID in This Age Group

  • Do NOT use stimulant laxatives (bisacodyl, senna) as first-line therapy due to unknown long-term safety in young children 1, 4
  • Avoid sodium phosphate preparations due to risk of electrolyte abnormalities and mucosal injury 1
  • Do not use bulk laxatives (psyllium) in young children with constipation 4
  • Magnesium-based laxatives should be used with caution if any renal concerns exist 1

Clinical Pearls

  • PEG 3350 significantly decreases colonic transit time (47.6 vs 55.3 hours compared to lactulose) and improves stool frequency from 3 to 7 bowel movements per week 2, 3
  • Success is defined as: ≥3 defecations per week and ≤1 encopresis episode every two weeks 2
  • The medication is tasteless and can be mixed with any beverage, improving compliance compared to lactulose 7
  • If constipation persists despite treatment, consider increasing the dose rather than switching medications immediately, as persistent constipation is associated with decreased symptom resolution 7

References

Guideline

Medication for Constipation in Children

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Guideline

Treatment of Constipation in Infants

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2026

Research

Polyethylene glycol 3350 without electrolytes for treatment of childhood constipation.

Canadian family physician Medecin de famille canadien, 2009

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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