What is the drug of choice for treating constipation in infants?

Drug of Choice for Constipation in Infants

For infants with constipation, lactulose is the first-line pharmacological treatment for those under 6 months of age, while polyethylene glycol (PEG) is recommended for infants over 6 months of age. 1

Treatment Algorithm for Infant Constipation

First-Line Approaches:

• Non-pharmacological interventions:
  • Ensure adequate hydration 2
  • Consider fruit juices containing sorbitol (prune, pear, and apple juices) for mild constipation 3
  • Rule out underlying causes (hypercalcemia, hypothyroidism, medications) 4

Pharmacological Management:

1. For infants under 6 months:

   • Lactulose: 2.5-10 mL daily in divided doses 5, 1
   • Reduce dose immediately if diarrhea occurs
   • Discontinue if diarrhea persists

2. For infants over 6 months:

   • Polyethylene glycol (PEG): Age-appropriate dosing 1, 6
   • Alternative: Lactulose 2.5-10 mL daily in divided doses 5

Management of Fecal Impaction

If fecal impaction is present:

1. Digital disimpaction may be necessary in severe cases 4
2. Follow with maintenance bowel regimen to prevent recurrence 4
3. Implement a regular toileting routine appropriate for the infant's developmental stage 4

Important Considerations

Efficacy and Evidence

The recommendation for lactulose in infants under 6 months is based on its safety profile and authorization for this age group 1. PEG has better evidence for effectiveness in older infants and children but is only authorized for use in infants over 6 months of age 1, 6.

Common Pitfalls to Avoid

• Undertreatment: Using insufficient doses leads to persistent symptoms 4
• Inadequate maintenance: Failing to continue treatment long enough after initial improvement 1
• Relying solely on dietary changes: While fruit juices containing sorbitol may help mild cases, established constipation requires medication 3, 1
• Missing organic causes: Always consider red flags that might indicate serious underlying conditions such as Hirschsprung's disease, hypothyroidism, or spinal cord abnormalities 6

Duration of Treatment

Treatment often needs to be continued for months to prevent relapse, as functional constipation tends to recur when treatment is discontinued prematurely 1, 6. The goal is to establish regular, painless bowel movements.

When to Refer

Consider referral to a pediatric gastroenterologist if:

• No response to appropriate first-line therapy
• Red flags suggesting organic disease
• Persistent symptoms despite adequate treatment 6, 7

Remember that constipation treatment in infants requires sufficient dosing for an adequate duration to be effective, with regular monitoring and adjustment as needed.