Comparing Drugs for Chronic Constipation
Laura Dean, MD.
National Center of Biotechnology Information (NCBI)
Created: November 1, 2007.
Chronic constipation is characterized by problems with bowel movements that last for at least 12 weeks. Problems include passing fewer than three bowel movements a week, straining during bowel movements, and lumpy or hard stool. If other gastrointestinal symptoms are present, such as bloating and abdominal pain, the constipation may be part of irritable bowel syndrome (IBS).
The management of constipation often begins with changes in diet (e.g. increase fluid intake), and behavior (e.g. use the bathroom at a specific time). Patients who do not respond to these changes are usually offered fiber supplements and simple laxatives. If the constipation persists and a specific cause cannot be found, many different drug options are available. However, despite constipation being a common problem, for which multiple drugs have been available for many years, the evidence for such treatments is largely missing.
The "Drug Class Review on Constipation Drugs" compares the safety and effectiveness of seven drugs used to treat chronic constipation in adults and children. A summary of the findings is below.
How do the drugs used to treat chronic constipation and irritable bowel syndrome with predominant constipation compare?
In adults, polyethylene glycol has been shown to be effective in the treatment of chronic constipation. Less evidence supports the efficacy of psyllium. The strongest evidence is for Tegaserod which has shown to be effective in not only chronic constipation in adults, but also constipation associated with irritable bowel syndrome in both adults and children. However, because of safety concerns, tegaserod is currently not available in the US. The evidence on lubiprostone has been published as abstracts only.
There is no evidence on the efficacy of docusate calcium, docusate sodium, and lactulose in treating chronic constipation in adults, and currently there are no studies on the general efficacy for the treatment of chronic constipation in children.
The evidence comparing the efficacy of two drugs is sparse and fraught with methodological limitations. Results indicate that polyethylene glycol is more effective than lactulose in adults and children and more than psyllium in adults. Docusate sodium had efficacy similar to psyllium in adult patients.
No studies exist on the efficacy of docusate calcium, docusate sodium, lactulose, polyethylene glycol, and psyllium for the treatment of irritable bowel syndrome.
We identified 535 citations from searches and reviews of reference lists. We included a total of 262 articles on an abstract level and retrieved those as full text articles for background information or to be reviewed for inclusion into the evidence report. Studies published as abstracts only are listed in Appendix B. In total we included 33 studies: seven head-to-head RCTs, 16 placebo controlled trials, one observational extension of an RCT, one meta-analysis, six observational studies, and two pooled data analyses. We retrieved 75 articles for background information.
Reasons for exclusions were based on eligibility criteria (Figure 1, QUORUM Tree).
Results of literature search*
Of the 33 included studies, 67% were financially supported by pharmaceutical companies, 6% were funded by governmental agencies or independent funds, and 3% received both, pharmaceutical and government funding. We could not determine a funding source for 24% of the included studies.
Because Irritable Bowel Syndrome (IBS) is considered a disease of its own, we distinguish between chronic constipation and chronic constipation associated with IBS throughout the report. Furthermore we present evidence on pediatric populations separate from findings in adult populations.
Because tegaserod is not available anymore for the general treatment of chronic constipation and chronic constipation associated with IBS, we are not discussing tegaserod studies in detail. Nevertheless, we are presenting the available evidence and report the major findings.