From the Guidelines
Combining lactulose with senna is generally acceptable when managing constipation, but should be done with caution. These medications work differently - lactulose is an osmotic laxative that draws water into the intestines, while senna is a stimulant laxative that increases intestinal contractions 1. When used together, they can provide more effective relief for severe or resistant constipation. However, this combination may cause increased cramping, diarrhea, or electrolyte imbalances.
Key Considerations
- Start with the recommended doses of each medication (typically 15-30 ml of lactulose 1-2 times daily and 8.6-17.2 mg of senna at bedtime) and adjust as needed 1.
- It's essential to maintain adequate hydration while taking these medications.
- This combination should be used for short-term management only, as long-term use of stimulant laxatives like senna can lead to dependence.
- If constipation persists despite using these medications, consult a healthcare provider to rule out underlying conditions requiring different treatment approaches. The American Gastroenterological Association and the American College of Gastroenterology formed a multidisciplinary guideline panel that conducted systematic reviews of the following agents: fiber, osmotic laxatives (polyethylene glycol, magnesium oxide, lactulose), stimulant laxatives (bisacodyl, sodium picosulfate, senna), secretagogues (lubiprostone, linaclotide, plecanatide), and serotonin type 4 agonist (prucalopride) 1. Lactulose is β-galactosido-fructose, a synthetic disaccharide not digested in the small intestine that exerts an osmotic laxative effect in the colon to promote peristalsis, and is approved by the FDA in the United States for the treatment of constipation at a dose of 10–20 g (15–30 mL or 1–2 packets) daily 1.
From the FDA Drug Label
Other laxatives should not be used, especially during the initial phase of therapy for portal-systemic encephalopathy because the loose stools resulting from their use may falsely suggest that adequate lactulose dosage has been achieved.
It is not recommended to combine lactulose with senna, as it is another type of laxative. The use of other laxatives with lactulose may interfere with the assessment of adequate lactulose dosage 2.
From the Research
Combining Lactulose with Senna
- There is no direct evidence to suggest that combining lactulose with senna is harmful or ineffective 3, 4, 5, 6, 7.
- A study from 1977 compared lactulose and senna in children with chronic constipation, and found that lactulose was more effective and had fewer side effects than senna 3.
- A 2021 study compared the efficacy of lactulose and senna plus ispaghula husk in patients with pre-dialysis chronic kidney disease and constipation, and found that both treatments were similar in efficacy 4.
- Another study from 2018 reviewed the safety of senna-based laxatives in children and found that they were safe for long-term treatment, with rare side effects such as perineal blistering 5.
- A 1993 study compared the safety and efficacy of a bulk laxative containing senna versus lactulose in geriatric patients with chronic constipation, and found that the bulk laxative plus senna was more efficient in treating constipation 6.
- A 2017 study compared the effectiveness of senna versus polyethylene glycol as laxative therapy in children with constipation related to anorectal malformation, and found that senna was more effective 7.
Potential Interactions
- There is no evidence to suggest that combining lactulose with senna would interact negatively or reduce the efficacy of either medication 3, 4, 5, 6, 7.
- However, it is essential to note that individual responses to medications may vary, and patients should consult their healthcare provider before combining any medications.