Is lactulose (a non-absorbable sugar) a suitable treatment option for a 1-month-old infant with constipation?

Lactulose for Constipation in 1-Month-Old Infants

Lactulose is effective and safe for treating constipation in infants younger than 6 months of age and should be considered as a first-line pharmacologic option when conservative measures fail. 1, 2

Dosing for Infants Under 6 Months

• The recommended initial daily oral dose for infants is 2.5 mL to 10 mL in divided doses 3
• Start at the lower end of the dosing range and titrate upward based on response 3
• The goal is to produce 2-3 soft stools daily 3
• If diarrhea develops, reduce the dose immediately; if diarrhea persists, discontinue lactulose 3

Evidence Supporting Use in Young Infants

• Lactulose/lactitol-based medications are specifically authorized and effective before 6 months of age, making them the preferred osmotic laxative in this age group 4
• A Middle East consensus statement confirms that lactulose has been shown to be effective and safe in infants younger than 6 months who are constipated 2
• Polyethylene glycol (PEG), while preferred in older infants (>6 months), is not approved for use in infants less than 6 months of age 2

Mechanism and Clinical Effects

• Lactulose is a synthetic disaccharide (β-galactosido-fructose) that is not digested in the small intestine and exerts an osmotic laxative effect in the colon to promote peristalsis 5
• Beyond increasing bowel movement frequency, lactulose has been shown to dramatically decrease fecal impactions and reduce the need for enemas 5

Important Safety Considerations

Critical warning: Infants receiving lactulose may develop hyponatremia and dehydration 3

• Monitor hydration status closely during treatment 3
• Watch for signs of electrolyte disturbance, particularly in young infants 3
• Ensure adequate fluid intake alongside lactulose therapy 1

Common Side Effects

• Bloating and flatulence are dose-dependent and very common side effects that may limit use in some patients 5
• These gastrointestinal symptoms can be minimized by starting at lower doses and titrating slowly 3

When to Use Lactulose in the Treatment Algorithm

Before Lactulose:

• Ensure adequate fluid intake in formula-fed infants 1
• Avoid excessive thickening of formula 1
• Consider glycerin suppositories for short-term relief 1

Lactulose as Second-Line:

• Use lactulose when conservative measures (hydration, formula adjustments, glycerin suppositories) have failed 1, 4
• Lactulose is appropriate for both disimpaction and maintenance therapy 4, 6

Alternative Considerations:

• For formula-fed infants with suspected cow's milk protein intolerance, trial extensively hydrolyzed or amino acid-based formula for 2-4 weeks before or alongside lactulose 1
• Fruit juices containing sorbitol (prune, pear, apple) are NOT recommended for young infants under 6 months 1

Duration of Treatment

• Continuous long-term therapy may be required for months to years because relapse of functional constipation is common 7, 8
• The rule for treatment is a sufficient dose for a long time 4
• Only 50-70% of children with functional constipation demonstrate long-term improvement despite treatment 8

Red Flags Requiring Further Evaluation

Stop and refer to pediatric gastroenterology if:

• Failure to thrive or poor weight gain 1
• Abdominal distension or tenderness 1
• Constipation persists despite appropriate interventions 1
• Development of significant hyponatremia or dehydration 3

Special Note on Breastfed Infants

• Breastfed infants rarely experience true constipation, and breastfeeding on demand should be continued 1
• If true constipation exists in breastfed infants, consider a 2-4 week maternal elimination diet restricting milk and eggs before initiating lactulose 1