Pediatric Lactulose Dosing
Constipation Dosing in Children
For pediatric constipation, lactulose dosing is weight-based: infants under 6 months should receive lactulose/lactitol-based medications at doses titrated to effect, while children over 6 months can receive 4-6 mL/kg/day (maximum 120 mL/day) for disimpaction, with maintenance dosing adjusted to achieve 2-3 soft stools daily. 1, 2
Disimpaction Protocol
- High-dose lactulose for fecal disimpaction: 4-6 mL/kg/day (maximum 120 mL/day) until resolution or up to 6 days 1
- This dosing achieves successful disimpaction in all patients by day 7, though polyethylene glycol shows faster response 1
- For infants under 6 months, lactulose/lactitol preparations are authorized and effective 2
Maintenance Therapy
- After disimpaction, reduce to maintenance dosing sufficient to maintain 2-3 soft bowel movements daily 1, 2
- The key principle is "sufficient dose for a long time" to prevent relapse 2
- Lactulose demonstrates superior tolerability compared to senna in children, with significantly fewer side effects (p<0.001) 3
Age-Specific Considerations
- Infants <6 months: Lactulose/lactitol-based medications are the authorized choice 2
- Children ≥6 months: Both lactulose and polyethylene glycol are effective options 2
- Lactulose is widely available, cost-effective, and safe across all pediatric age groups 1
Hepatic Encephalopathy Dosing in Children
While specific pediatric dosing for hepatic encephalopathy is not well-established in guidelines, extrapolation from adult protocols suggests starting with 30-45 mL every 1-2 hours until achieving 2 soft bowel movements daily, then transitioning to maintenance dosing of 30-45 mL 3-4 times daily, with careful weight-based adjustments for smaller children. 4, 5, 6
Acute Management Protocol
- Initial aggressive dosing: 30-45 mL (20-30 g) every 1-2 hours orally until at least 2 soft bowel movements are produced daily 4, 5
- For severe cases (West-Haven grade 3-4) or inability to take oral medications, use rectal administration 4
Rectal Administration for Severe Cases
- Retention enema preparation: Mix 300 mL lactulose with 700 mL water or physiologic saline 4, 6
- Administer 3-4 times daily until clinical improvement 4
- Retain solution in intestine for at least 30 minutes for maximum effectiveness 4
- Transition to oral maintenance therapy once patient can tolerate oral intake 6
Maintenance Dosing
- Standard maintenance: 30-45 mL (20-30 g) administered 3-4 times daily 4, 6
- Therapeutic target: Titrate to achieve 2-3 soft stools per day 5, 6
- Continue indefinitely in patients with cirrhosis who have experienced hepatic encephalopathy 6
Critical Safety Considerations
Monitoring Requirements
- Electrolyte monitoring: Check sodium and potassium frequently, especially with rectal administration 4, 5
- Assess for dehydration and hypernatremia regularly, particularly in patients on diuretics 4, 6
- Monitor for perianal skin breakdown with chronic use 5
Common Pitfalls to Avoid
- Overuse complications: Excessive lactulose can cause aspiration, dehydration, hypernatremia, severe perianal irritation, and paradoxically precipitate hepatic encephalopathy 5, 6
- Do not escalate indefinitely: If no response after appropriate dosing, investigate precipitating factors (infection, GI bleeding, medications) rather than continuing to increase lactulose 5
- The misconception that lack of effect requires much larger doses is dangerous 5