Lactulose Oral: Dosing and Precautions
Lactulose guidance for prevention of constipation in patients taking opioid analgesics, with stool-response monitoring.
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Source reviewed
January 2024
Guide category
Oral drugs
Safety boundary
Educational medicine information, not personal medical advice.
Kenza Health Hub presents this medicine page as structured health education. Check dose, route, interactions, pregnancy or breast-feeding considerations, and local protocol with a qualified clinician or pharmacist. Read our medical editorial policy.
Therapeutic action
Osmotic laxative.
Indications
Prevention of constipation in patients taking opioid analgesics such as codeine and morphine.
Forms and strengths
- 10 g/15 ml oral solution, to be administered using a measuring device.
Dose and duration
Start lactulose when analgesic treatment continues more than 48 hours.
Lactulose must be taken daily until the end of the opioid treatment. Regular follow up of stool frequency and consistency is essential in order to adjust dosage correctly.
- Child under 1 year: 5 ml daily (3.3 g daily).
- Child from 1 to 6 years: 5 to 10 ml daily (3.3 to 6.7 g daily).
- Child from 7 to 14 years: 10 to 15 ml daily (6.7 to 10 g daily).
- Child over 14 years and adult: 15 to 45 ml daily (10 to 30 g daily).
Contra-indications, adverse effects, precautions
- Do not administer to patients with Crohn's disease, ulcerative colitis, intestinal obstruction, or undiagnosed abdominal pain.
- May cause abdominal discomfort, flatulence, and diarrhoea.
- In the event of diarrhoea, exclude faecal impaction and intestinal obstruction, then reduce the dose.
- Pregnancy: no contra-indication.
- Breast-feeding: no contra-indication.
Source
MSF Essential drugs practical guidelines (January 2026)
This page combines source-derived medicine reference sections with Kenza editorial context, while leaving out the Storage and Remarks sections from the source batch.
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