What is the recommended starting dose of Kristalose (lactulose) for infants (≤12 months) and for children aged 1 year to adolescence?

Kristalose (Lactulose) Dosing for Pediatric Patients

For infants ≤12 months, the FDA-approved initial dose is 2.5 to 10 mL daily in divided doses; for children and adolescents aged 1 year and older, the recommended total daily dose is 40 to 90 mL daily in divided doses, adjusted to produce 2-3 soft stools per day. 1

Infant Dosing (≤12 months)

• Start with 2.5 to 10 mL daily in divided doses for infants under 12 months of age 1
• The dose should be titrated based on response, with the goal of producing 2-3 soft stools daily 1
• If diarrhea develops, reduce the dose immediately and discontinue if diarrhea persists 1
• Research supports that lactulose is authorized and effective before 6 months of age, though polyethylene glycol (PEG) is preferred after 6 months 2

Children and Adolescents (1 year to 18 years)

• The total daily dose ranges from 40 to 90 mL daily for older children and adolescents 1
• Divide the total daily dose into 2-4 administrations throughout the day 1
• The subjective goal is to produce 2-3 soft stools daily, which guides dose titration 1

Dose Titration Strategy

• Adjust the dose every 1-2 days based on stool frequency and consistency 1
• If the initial dose causes diarrhea, reduce immediately 1
• The rule for successful treatment is using a sufficient dose for a prolonged duration 2
• Typical adult dosing is 30-45 mL (2-3 tablespoonfuls) three to four times daily, which can inform dosing for larger adolescents 1

Special Considerations for Fecal Impaction

• For disimpaction therapy, higher doses are required: 4-6 mL/kg/day (maximum 120 mL/day) until resolution or up to 6 days 3
• Research demonstrates that lactulose at these higher doses achieves successful disimpaction by day 7 in all patients, though PEG shows faster response 3
• Once disimpaction is achieved, reduce to maintenance dosing 1

Administration Guidelines

• Lactulose can be administered orally regardless of meals, though giving with meals may improve gastrointestinal tolerability 4
• The medication is available as a syrup/solution that does not require reconstitution 1
• Continuous long-term therapy may be indicated to prevent recurrence of symptoms 1

Important Safety Considerations and Common Pitfalls

• Do not underdose: The most common error is using insufficient doses that fail to produce the target 2-3 soft stools daily 1, 2
• Monitor for excessive diarrhea: This indicates overdosing and requires immediate dose reduction 1
• Bloating and flatulence are dose-dependent side effects that may limit use in some patients 4
• Lactulose is less effective than PEG for both disimpaction and maintenance therapy in most studies, though it remains a reasonable alternative when PEG is unavailable or not tolerated 3, 5, 6
• Compliance issues: Research shows lactulose has lower compliance rates (60-90%) compared to other laxatives, particularly during prolonged therapy, due to taste and side effects 6

Comparative Effectiveness

• While lactulose is FDA-approved and widely available, PEG-based laxatives demonstrate superior efficacy with better tolerability and acceptance in children over 6 months of age 2, 5
• Lactulose shows significantly more side effects (particularly abdominal discomfort and flatulence) compared to PEG formulations 5, 7
• However, lactulose is cheap, widely available, and remains an effective option when PEG is not accessible 3