Docusate for constipation: Money down the toilet?

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Constipation. It’s not something we often talk about in polite conversation but, given how common it is, perhaps we should. As much as one quarter of all adults suffer from it, and an estimated three out of every four seniors living in long-term care have issues with constipation. Almost everyone who takes opioids regularly for chronic pain also experiences constipation symptoms.

Although we have a tendency to joke about the condition, the symptoms really are no laughing matter. Difficulty passing stools, abdominal cramping, hard stools, and an inability to completely pass stool can be a minor annoyance for some but may be severely debilitating for others, having a huge impact on a person’s quality of life.

Fortunately, there are a number of treatment options for constipation. Bulking agents such as psyllium, osmotic laxatives like lactulose, and stimulant laxatives such as sennosides and bisacodyl are all available. But stool softeners, commonly called docusate, are often the first choice of clinicians for their patients with constipation – especially patients who are in hospital or in long-term care, or those taking opioids. They are safe, are well-tolerated by patients, don’t tend to interact with other medications, and are low-cost. In fact, “bowel protocols” that include the routine use of stool softeners are in place in many hospitals and long-term care facilities across Canada.

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Given how frequently stool softeners are prescribed and how commonplace their use has become, we might forget to stop for a moment and ask ourselves: “But do they really work?” And even if we did think to ask the question, how would we find the answer?

CADTH — an independent, evidence-based agency that assesses health technologies — finds and summarizes the research on drugs, medical devices, and procedures. CADTH’s Rapid Response service provides summaries and critical appraisal of the evidence in as little as 30 days and recently was asked to evaluate if docusate really is effective in the prevention or treatment of constipation. And the results were a little surprising.

Despite how common constipation is and the frequent use of docusate for its prevention and treatment, there isn’t a lot of high-quality medical evidence out there. CADTH’s search of the literature found only five studies published since 2004 that were relevant to the question at hand and could be included in the review.

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And what the evidence had to say may also be a surprise for some. In the studies reviewed, docusate did not work any better than placebo (no active medication at all) in patients taking opiates. For these patients it does not appear to improve the symptoms of constipation, it does not increase stool frequency, and it does not result in softer stools. Adding docusate to a stimulant laxative (sennosides) worked no better to treat constipation in hospice patients than giving the sennosides alone. In general, there was a lack of clinical evidence for docusate in the prevention and treatment of constipation. There were some limitations to the evidence – studies were small, tended to focus on one patient population, and didn’t always control for the use of other medications for constipation. Studies in patient populations other than the elderly in long-term care or patients taking opiates were not found. However, the bottom line is that the review of the available evidence did not support the use of docusate for the prevention or management of constipation.

What does all this mean for patients with constipation and their healthcare providers? To start, even though docusate is inexpensive, prescribing a medication that is not clinically effective can never be cost-effective. And given that docusate is so widely used, it could be costing the healthcare system a significant amount of money – as well as time and effort. While patients are using docusate they may put off trying other constipation medications, which could perhaps even lead to harm if a patient’s constipation gets worse while taking it.

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Knowing what the evidence is on a drug like docusate – one that is commonly used but of questionable benefit – is helpful to clinicians and decision-makers faced with tough treatment decisions. A lack of evidence, together with other important considerations, can lead to the discontinuation of a drug or a reduction in its use. This may end up being the case for stool softeners when it comes to seniors in long-term care and patients taking opiates.

If you’d like more information about the CADTH Rapid Response report on stool softeners – or on a variety of other drugs, devices, or procedures – they are all freely available on the CADTH website: www.cadth.ca/RapidResponse. Here you’ll find the reports listed chronologically as they are completed or you can use the search function at the top right of your screen.

To learn more about CADTH, visit www.cadth.ca, follow us on Twitter: @CADTH_ACMTS, or talk to our Liaison Officer in your region: http://www.cadth.ca/en/services/liaison-officer.