What are the long-term effects of stimulant laxatives, such as senna or bisacodyl, on bowel function and overall health?

From the Guidelines

Long-term use of stimulant laxatives, such as senna or bisacodyl, is not recommended due to potential harmful effects on bowel function and overall health, and instead, patients should consider alternative treatments, such as bulk-forming laxatives, increased dietary fiber and water intake, and regular physical activity, as suggested by the American Gastroenterological Association guideline 1. The potential risks associated with long-term stimulant laxative use include dependence on the medication, decreased natural bowel function, and chronic constipation when the laxatives are stopped. Additionally, prolonged use can lead to electrolyte imbalances, particularly potassium depletion, which can cause muscle weakness, abnormal heart rhythms, and kidney problems. The colon can also become damaged over time, developing a condition called cathartic colon, where the bowel loses its normal function and structure. Users may also develop tolerance, requiring increasingly higher doses to achieve the same effect, and melanosis coli, a darkening of the colon lining, can occur with long-term senna use. Some key points to consider when managing constipation include:

• The use of fiber supplementation, such as psyllium, as a first-line therapy for chronic idiopathic constipation (CIC) 1
• The recommendation for short-term use of bisacodyl or sodium picosulphate as rescue therapy for CIC, with the understanding that long-term use may be appropriate but requires further study to understand tolerance and side effects 1
• The importance of dietary assessment to determine total fiber intake from diet and supplements, and the encouragement of adequate hydration with the use of fiber supplements 1
• The potential side effects of laxatives, including abdominal distension, loose stool, flatulence, and nausea, and the need to weigh these against the benefits of treatment 1 Overall, the management of constipation requires a comprehensive approach that takes into account the individual patient's needs and circumstances, and considers the potential risks and benefits of different treatment options. The American Gastroenterological Association guideline suggests a strong recommendation for the use of bisacodyl or sodium picosulphate short-term or as rescue therapy for CIC, but emphasizes the need for further study on the long-term effects of these medications 1.

From the Research

Long-term Effects of Stimulant Laxatives on Bowel Function

• The use of stimulant laxatives, such as senna or bisacodyl, has been established as a reliable treatment for constipation, with a comprehensive review of 43 publications finding no convincing evidence that these laxatives are associated with the development of colon cancer 2.
• In fact, chronic constipation itself has been reported to potentially increase the risk of colon cancer, suggesting that the use of stimulant laxatives might reduce this risk 2.
• A systematic review of 41 randomized controlled clinical trials found that polyethylene glycol-based preparations and senna were supported by good evidence as first-line laxatives, while bisacodyl and sodium picosulfate were supported by modest evidence 3.

Safety and Efficacy of Long-term Treatment with Stimulant Laxatives

• A review of clinical trial evidence found that bisacodyl and sodium picosulfate were effective in treating constipation, with a positive global assessment of efficacy obtained in 78-99% of patients treated with these laxatives 4.
• However, the evidence base does not support the use of stimulant laxatives for more than four weeks, and longer-term RCTs and epidemiological studies are needed to investigate the effects and safety of these laxatives on the longer term 4.
• A study of senna-based laxatives in children found that they were safe when used as long-term treatment for constipation, with the only significant side effect being perineal blistering, which was related to high doses and long periods of stool to skin contact 5.

Potential Risks and Side Effects of Stimulant Laxatives

• The potential harmful effects of stimulant laxatives on the gastrointestinal system, including carcinogenicity, have been assessed in several studies, with no convincing evidence found to support these concerns 2, 6.
• Common adverse effects of stimulant laxatives include abdominal pain, cramping, bloating, diarrhea, and nausea, with these effects generally being mild and frequent 3, 4.
• Pediatric caregivers should be aware of the rare side effect of skin blistering associated with senna-based laxatives, and advise families to change diapers frequently to reduce stool to skin exposure 5.