From the Guidelines
The recommended dose of lactulose for constipation is 10–20 g (15–30 mL or 1–2 packets) daily, which can be increased to 40 g (60 mL or 2–4 packets) daily if needed, as per the American Gastroenterological Association-American College of Gastroenterology clinical practice guideline 1.
Key Considerations
- Lactulose is a synthetic disaccharide that exerts an osmotic laxative effect in the colon to promote peristalsis.
- The dose may be adjusted based on individual response and tolerance, with consideration of potential side effects such as bloating and flatulence, which are dose-dependent.
- Lactulose can be considered if symptoms of chronic idiopathic constipation (CIC) have failed to improve with fiber and over-the-counter (OTC) laxatives, and individuals do not experience significant bloating or abdominal pain with lactulose use 1.
Important Details
- Lactulose is approved by the FDA in the United States for the treatment of constipation.
- It is widely available in other countries and can be used for short-term constipation relief or as a long-term therapy for chronic constipation.
- Patients should be advised to take lactulose with a full glass of water or juice to improve the taste and enhance hydration, and to reduce the dose if they experience excessive bloating, gas, or diarrhea.
- Consultation with a healthcare provider is recommended if constipation persists beyond two weeks of treatment.
From the FDA Drug Label
The usual adult, oral dosage is 2 to 3 tablespoonfuls (30 mL to 45 mL, containing 20 grams to 30 grams of lactulose) three or four times daily. The dosage may be adjusted every day or two to produce 2 or 3 soft stools daily The recommended dose of lactulose for constipation in adults is 2 to 3 tablespoonfuls (30 mL to 45 mL), containing 20 grams to 30 grams of lactulose, taken three or four times daily. The dose may be adjusted to produce 2 or 3 soft stools daily 2.
- Key points:
- Initial dose: 2 to 3 tablespoonfuls (30 mL to 45 mL)
- Frequency: three or four times daily
- Adjustment: every day or two to produce 2 or 3 soft stools daily
From the Research
Lactulose Dosage for Constipation
- The ideal dosage of lactulose for constipation is not explicitly stated in the provided studies, but its effectiveness is mentioned in several studies 3, 4, 5.
- A study from 1993 compared the efficacy and cost-effectiveness of lactulose and a senna-fibre combination in treating constipation in long-stay elderly patients, with lactulose being administered at a dose of 15 ml twice daily 5.
- Another study from 2021 mentions lactulose as an effective and safe therapy for both long and short-term treatment of pediatric functional constipation, but does not specify the dosage 4.
- A 2007 review of treatment options for chronic constipation mentions lactulose as one of the traditional pharmacologic agents that may benefit some patients with constipation, but notes that the clinical evidence supporting its use is limited 3.
- A 2020 review of medications for constipation discusses various treatment options, including lactulose, but does not provide specific dosage information 6.
- An overview of interventions for constipation in adults from 2020 discusses the complexity of diagnosing and treating constipation, but does not provide specific guidance on lactulose dosage 7.