Lactulose Dosing for a 2-Year-Old Child
For a 2-year-old child with constipation, start with 2.5-10 mL of lactulose daily in divided doses, titrating to produce 2-3 soft stools per day. 1
Pediatric Dosing Guidelines
The FDA-approved dosing for young children is based on limited but established evidence:
- Initial dose for infants and young children: 2.5-10 mL daily in divided doses 1
- Goal of therapy: Produce 2-3 soft stools daily 1
- Dose adjustment: If diarrhea occurs, reduce the dose immediately; if diarrhea persists despite reduction, discontinue lactulose 1
For older children and adolescents, the total daily dose ranges from 40-90 mL, but a 2-year-old would fall into the younger pediatric category requiring the lower dosing range 1
Practical Dosing Strategy
Start conservatively with 2.5-5 mL once or twice daily, then titrate upward based on response over several days 1. The subjective goal is achieving 2-3 soft stools daily without causing diarrhea 1.
Research supports lactulose as effective and well-tolerated in young children, with one controlled trial demonstrating significantly better outcomes and fewer side effects compared to senna in children under 15 years 2. Another study confirmed lactulose effectiveness for disimpaction at higher doses (4-6 mL/kg/day, maximum 120 mL/day) when fecal impaction is present 3.
Critical Safety Considerations
Monitor closely for dehydration and electrolyte disturbances, as excessive lactulose can cause dehydration, hypernatremia, and severe perianal skin irritation in young children 4. The aspiration risk increases if excessive diarrhea occurs 4.
Common pitfall: Do not assume that lack of effect requires much larger doses—instead, search for other causes or consider alternative therapies 4. Overuse can paradoxically worsen clinical status through fluid and electrolyte complications 4.
Alternative Considerations
For children over 6 months of age, polyethylene glycol (PEG) is also authorized and may be considered if lactulose is not tolerated or effective 5. However, lactulose remains a reasonable first-line option given its safety profile, lower cost, and wide availability 3.