What are the best treatments for constipation in an 18-month-old child?

Treatment of Constipation in an 18-Month-Old Child

For an 18-month-old with constipation, start with polyethylene glycol (PEG) 3350 at 0.8-1 g/kg/day as first-line pharmacological therapy, combined with dietary modifications including increased fluids and age-appropriate fiber-rich foods. 1

Initial Assessment

Before starting treatment, rule out fecal impaction through digital rectal examination, as impaction requires disimpaction before maintenance therapy can succeed. 1 If impaction is present, use glycerin suppositories as the preferred first-line option for this age group, as they are safe and effective rectal stimulants. 1

First-Line Pharmacological Management

Polyethylene glycol (PEG) 3350 is the laxative of first choice for children 6 months and older. 1

• Dose: 0.8-1 g/kg/day initially, adjusted to produce 2-3 soft, painless stools daily 1
• PEG is effective, well-tolerated, and has the strongest evidence base in pediatric constipation 2, 3, 4
• Treatment duration typically requires months of maintenance therapy to prevent relapse 1, 4

Alternative first-line options include:

• Lactulose: For infants under 6 months, initial dose 2.5-10 mL daily in divided doses; for older children 40-90 mL daily 1, 5
• Sorbitol-containing fruit juices (prune, pear, apple) can increase stool frequency and water content 1

Dietary and Non-Pharmacological Interventions

Implement these measures alongside pharmacological therapy:

• Increase fluid intake to maintain proper hydration 1
• Add age-appropriate high-fiber foods: fruits, vegetables, whole grains, legumes 1
• Continue breast-feeding on demand or full-strength formula 1
• Encourage regular physical activity appropriate for age 1
• Establish regular toileting schedules once the child is toilet-training age 1

Treatment Algorithm

Step 1: Disimpaction (if needed)

• Use glycerin suppositories or high-dose PEG for several days 1, 3
• Avoid suppositories if neutropenia, thrombocytopenia, recent colorectal surgery, anal trauma, or severe colitis present 1

Step 2: Maintenance Therapy

• Continue PEG at maintenance doses for months, adjusting based on stool output 1
• Goal: 2-3 soft, painless stools daily 1
• Maintain dietary modifications throughout 1

Step 3: Gradual Weaning

• Maintenance may need to continue for many months before normal bowel motility returns 1
• Premature discontinuation leads to 40-50% relapse rates within 5 years 1

Critical Pitfalls to Avoid

• Do not rely solely on dietary changes without addressing impaction if present - this worsens constipation 1
• Do not use stimulant laxatives (like bisacodyl) as first-line therapy - osmotic agents are preferred 1
• Do not discontinue treatment prematurely - parents often stop too soon before the child regains normal bowel function 1
• Do not use bisacodyl in infants under 6 months - no safety or efficacy data exists for this age group 1
• If diarrhea develops with lactulose, reduce dose immediately or discontinue 5

Important Considerations

Aggressive constipation management is particularly important as it can decrease urinary tract infections and reduce intervention needs in children with vesicoureteral reflux. 1 Treatment success requires months of consistent therapy, as only 50-70% of children demonstrate long-term improvement despite treatment. 4