What is the recommended treatment for constipation in pediatric patients using Miralax (polyethylene glycol 3350) or Colace (docusate)?

Pediatric Constipation Treatment: Miralax vs Colace

Direct Recommendation

Polyethylene glycol 3350 (Miralax) is the first-line treatment for constipation in children, while docusate sodium (Colace) is not recommended due to lack of experimental evidence supporting its efficacy in pediatric populations. 1

Evidence-Based Treatment Algorithm

First-Line Therapy: Polyethylene Glycol 3350 (Miralax)

PEG 3350 should be initiated as the primary laxative for pediatric constipation across all age groups. 1

Dosing by age:

• Infants <18 months: Mean effective dose is 0.78 g/kg/day (range 0.26-1.26 g/kg/day), with 97.6% efficacy 2
• Children ≥18 months: Mean effective dose is 0.84 g/kg/day (range 0.27-1.42 g/kg/day) 3
• Standard adult formulation: 17g once daily mixed in 4-8 oz of liquid 4

Administration details:

• Mix powder in water, juice, soda, coffee, or tea 4
• Adjust dose every 3 days to achieve 2 soft stools per day 3
• First bowel movement typically occurs within 2-4 days 4

Why Colace (Docusate) Should NOT Be Used

Docusate sodium lacks experimental evidence supporting its use in pediatric constipation management and is explicitly not recommended in current guidelines. 1 This represents a critical pitfall in pediatric constipation management—despite its widespread historical use, stool softeners like docusate have no proven efficacy in children.

Clinical Outcomes with PEG 3350

Efficacy data demonstrates robust improvements across multiple parameters:

• Weekly stool frequency increases from 2.3 to 16.9 stools (p<0.0001) 3
• Stool consistency improves significantly (p<0.0001) 3
• In children with soiling, weekly events decrease from 10.0 to 1.3 (p=0.003) 3
• In children with dysfunctional elimination, 18 became completely dry and 26 had decreased wetting 5

Additional benefits in special populations:

• Voided volume increases (146 vs 210 ml, p<0.0001) 5
• Post-void residual decreases significantly (92 vs 48 ml, p<0.0001) 5
• Urinary tract infections decrease when constipation is treated 1

Safety Profile and Adverse Effects

PEG 3350 demonstrates excellent tolerability:

• Most common side effect is diarrhea (occurring in 9/46 patients in one study), which resolves with dose adjustment 5
• Occasional nausea, stomach fullness, cramping, or gas may occur 4
• Rare allergic reactions (hives, skin rashes) have been reported 4
• Safe for long-term use (studied up to 21 months) 2
• All children in controlled studies found PEG palatable and were satisfied with treatment 3

Duration of Therapy

Treatment should be maintained for extended periods:

• Optimal results occur between 1-2 weeks initially 4
• Continue until child establishes regular bowel habits, which may require several months 1
• Mean duration in infant studies was 6.2 ± 5 months (range 3 weeks to 21 months) 2
• Treatment goal is one non-forced bowel movement every 1-2 days 1

Alternative Agents (When PEG Fails or Is Unavailable)

If PEG 3350 is inadequate or not tolerated:

• Lactulose is the recommended alternative, though less effective than PEG 1
• Stimulant laxatives (senna, bisacodyl) may be added if inadequate response to osmotic laxatives alone 1
• Liquid paraffin (mineral oil) shows efficacy but use with caution in infants due to aspiration risk 1

Agents to Avoid

Do not use the following in pediatric constipation:

• Docusate sodium (Colace): No experimental evidence of efficacy 1
• Bulk-forming laxatives (psyllium): Unlikely to control constipation effectively 1
• Sodium phosphate preparations: Avoid in children <12 years due to adverse effects 1

Monitoring and Follow-Up

Essential monitoring parameters:

• Keep a calendar of bowel movements to establish baseline and judge treatment effect 1
• Regular follow-up is essential to sustain motivation and improve outcomes 1
• Adjust dose based on stool frequency and consistency 3
• Watch for excessive loose stools indicating need for dose reduction 4

Critical Pitfalls to Avoid

Common errors in pediatric constipation management:

• Using docusate (Colace) based on historical practice rather than evidence 1
• Discontinuing PEG too early before bowel habits normalize (may need months) 1
• Inadequate dose titration—adjust every 3 days to achieve optimal response 3
• Using bulk-forming laxatives which are ineffective in children 1
• Failing to address constipation in children with urinary symptoms 5