From the FDA Drug Label
Pediatric: Very little information on the use of lactulose in young children and adolescents has been recorded. As with adults, the subjective goal in proper treatment is to produce 2 or 3 soft stools daily. On the basis of information available, the recommended initial daily oral dose in infants is 2. 5 mL to 10 mL in divided doses. For older children and adolescents the total daily dose is 40 mL to 90 mL. If the initial dose causes diarrhea, the dose should be reduced immediately. If diarrhea persists, lactulose should be discontinued The recommended pediatric dosing for lactulose is:
- Infants: 2.5 mL to 10 mL per day in divided doses
- Older children and adolescents: 40 mL to 90 mL per day If the initial dose causes diarrhea, it should be reduced immediately, and if diarrhea persists, lactulose should be discontinued 1
From the Research
Lactulose dosing for children should be individualized based on age, weight, and indication, with a recommended starting dose of 1-3 mL/kg/day for constipation and 2-3 mL/kg/day for hepatic encephalopathy, as supported by the most recent and highest quality study 2.
Key Considerations
- For constipation in children, the dose can be divided into 1-2 doses, with a maximum of 40 mL/day.
- For infants under 1 year, start with 2.5-5 mL/day; children 1-5 years typically need 5-10 mL/day; and children 6-12 years require 10-20 mL/day.
- For hepatic encephalopathy, higher doses may be needed, titrated to produce 2-3 soft stools daily.
Mechanism of Action
- Lactulose works as an osmotic laxative by drawing water into the intestinal lumen and also reduces ammonia absorption in the colon by acidifying the environment.
Common Side Effects
- Abdominal cramping, bloating, and flatulence are common side effects, and the dose should be adjusted based on clinical response, aiming for soft, formed stools.
Monitoring and Adjustment
- If watery diarrhea occurs, the dose should be reduced, and lactulose typically takes 24-48 hours to work, so patience is needed when initiating therapy.
Recent Evidence
- A 2022 systematic review and meta-analysis 2 compared polyethylene glycol electrolyte solution versus lactulose for treatment of hepatic encephalopathy, finding that polyethylene glycol has a beneficial effect on the treatment of HE, leading to more rapid HE resolution during the first 24 hours and shortening the length of stay without increasing the rate of adverse effects.
- Another study in 2021 3 also found that polyethylene glycol leads to a higher drop in the HESA Score and thus leads to a faster resolution of HE compared with lactulose.