From the Guidelines
For elderly patients with constipation not responding to PEG and senna, a typical PRN lactulose dosing would be 15-30 mL orally once daily, which can be increased to twice daily if needed, as recommended by the American Gastroenterological Association-American College of Gastroenterology clinical practice guideline 1. The dose may be increased to 40 g (60 mL or 2–4 packets) daily if needed, but it is essential to start with the lower dose of 15 mL and titrate up based on response 1. Lactulose works as an osmotic laxative by drawing water into the intestinal lumen and also produces an acidic environment in the colon that promotes bowel movements. Some key points to consider when using lactulose in elderly patients include:
- It typically takes 24-48 hours to produce effects 1
- Side effects may include bloating, flatulence, and abdominal cramping, which tend to be more pronounced in elderly patients 1
- If diarrhea occurs, the dose should be reduced
- Ensure adequate fluid intake while using lactulose to prevent dehydration
- For elderly patients with renal or hepatic impairment, start with lower doses and monitor closely 1
- If lactulose is ineffective after several days at maximum dosing, consider consulting with a healthcare provider for alternative approaches. Two RCTs studied the efficacy of lactulose syrup for the treatment of CIC in elderly participants, and the results support the use of lactulose as a treatment option for constipation in this population 1.
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 typical PRN lactulose dosing in elderly for constipation, if PEG and senna are not working, would be to start with the recommended adult dose of 2 to 3 tablespoonfuls (30 mL to 45 mL) and adjust as needed to produce 2 or 3 soft stools daily 2.
- The dose may be adjusted every day or two.
- Hourly doses are not typically used for constipation, but rather for the initial phase of therapy of portal-systemic encephalopathy.
- Long-term therapy is indicated to lessen the severity and prevent the recurrence of portal-systemic encephalopathy, but this is not directly relevant to constipation treatment.
- Elderly patients may require closer monitoring and dose adjustments due to potential decreased renal function and other comorbidities, but the label does not provide specific guidance on this.
From the Research
Typical PRN Lactulose Dosing in Elderly for Constipation
When polyethylene glycol (PEG) and senna are not effective, lactulose may be considered as an alternative treatment for constipation in elderly patients.
- The typical dosing of lactulose is not explicitly stated in the provided studies, but it is mentioned as an osmotic laxative that can be used in elderly patients 3.
- A study comparing lactulose and PEG found that PEG is more effective in treating chronic constipation, but lactulose is still a viable option 4, 5.
- The use of lactulose should be considered on a case-by-case basis, taking into account the patient's individual needs and medical history 6, 7.
- It is essential to note that lactulose is generally considered safe and effective for short-term use in elderly patients, but long-term use may require closer monitoring 3.
Considerations for Lactulose Use
- Lactulose is an osmotic laxative that can help soften stool and increase bowel movements 4, 5.
- The effectiveness and safety of lactulose in elderly patients have been demonstrated in several studies, although the quality of the evidence is not always high 3.
- As with any medication, it is crucial to weigh the potential benefits and risks of lactulose use in elderly patients and to monitor for any adverse effects 6, 7.