Lactulose Dosing for Infants
For infants, the recommended initial oral dose of lactulose is 2.5 to 10 mL daily in divided doses, with the goal of producing 2-3 soft stools daily. 1
FDA-Approved Pediatric Dosing
The FDA drug label provides the most authoritative guidance for lactulose use in infants:
- Initial dose for infants: 2.5 to 10 mL daily in divided doses 1
- Older children and adolescents: 40 to 90 mL total daily dose 1
- Therapeutic goal: Produce 2-3 soft stools daily 1
Dose Adjustment Strategy
If diarrhea occurs, reduce the dose immediately; if diarrhea persists despite dose reduction, discontinue lactulose. 1 This is critical because infants are particularly vulnerable to dehydration and electrolyte disturbances from excessive laxative effect.
Alternative Dosing Information
Research literature suggests that in pediatric patients, lactulose dosing ranges from 500-750 mg/kg/day, though this represents a higher dose range typically used for constipation management. 2 However, the FDA label's volume-based dosing (2.5-10 mL daily) should take precedence as the primary guidance.
Age-Specific Considerations
- Infants under 6 months: Lactulose/lactitol-based medications are authorized and effective 3
- Infants over 6 months: Polyethylene glycol becomes an additional option 3
Important Clinical Pitfalls
Avoid overdosing, as excessive lactulose can cause:
- Dehydration 4, 5
- Hypernatremia 4, 5
- Severe perianal skin irritation 4, 5
- Aspiration risk if excessive diarrhea occurs 4
The misconception that lack of effect requires much larger doses is dangerous—instead, search for other causes or consider alternative therapies. 4
Duration of Treatment
For chronic constipation, treatment should be maintained at a sufficient dose for a prolonged period to restore colonic motility and prevent relapse. 3 The dose should be titrated based on stool frequency and consistency, not arbitrarily increased.