Ask the Expert: Conservative Management of Constipation in Older Adults
Ask the Expert: Conservative Management of Constipation in Older Adults
Constipation is estimated to affect as many as 40% of older adults. Although constipation has multiple etiologies, the standard advice when patients present with constipation is conservative treatment with lifestyle modification (ie, diet and exercise) and over-the-counter (OTC) agents. However, this standard of care is in need of scrutiny, according to Lawrence Leung, MBBChir, CCFP, FRACGP, FRCGP, Department of Family Medicine, Queen’s University, Canada. In a recent review of the literature (www.jabfm.org/content/24/4/436.full), Leung and colleagues reported that treatment of constipation should be guided by the evidence and individualized according to its etiology. Clinical Geriatrics® (CG) had the opportunity to interview Leung about the body of evidence supporting the use of conservative treatment in the management of constipation in older adults.
CG: What challenges do clinicians face when treating and managing constipation in their older adult patients?
Leung: The main challenges in treating and managing chronic constipation in older adults include varying diagnoses of constipation (in terms of frequency of motion, texture of stool or subjective feeling of defecation), degree of underdiagnosis in the older adult population (especially in those with cognitive impairment), and the degree of self-medication with OTC medications. In view of the common occurrence of constipation, clinicians in a busy practice very often prescribe medications without considering the possibility of structural etiology of constipation in older adult patients (ie, pelvic-floor dysfunction), in which case will respond poorly to laxatives.
When patients present with concerns of constipation, it is common practice for physicians to recommend that patients modify their lifestyle first, for example, by increasing dietary fiber, fluids, and exercise—but what does the literature reveal with regard to the effectiveness of these modifications?
In our review, the standard advice of increasing dietary fiber, fluids, and exercise as dietary lifestyle modifications is not universally beneficial to all patients with constipation. For dietary fiber, evidence is inconclusive (level 2C) and benefits are only seen in patients with actual fiber deficiency. Increasing exercise can decrease self-reported symptoms in women but evidence is not strong (level 2C). A large prospective study revealed a link between fluid intake and constipation, but there were no trials looking at effects of increased fluids on constipation (level 2C). In summary, there will only be benefits for increasing fiber, fluids, and exercise if there is an actual lack of any of the three, and physicians should refrain from encouraging such increase as standard advice.
There is a plethora of OTC agents that physicians can recommend to patients with constipation. These include oral osmotics, oral bulk-forming agents, oral stool softeners, oral stimulations, and rectal stimulants. Could you briefly discuss what the literature says about the efficacy and side effects of each of these OTC products?
Bulk-forming agents are mainly fiber supplements that absorb water to increase the bulk of the stool and enhance bowel motions. Examples are bran, psyllium, and methylcellulose. Of the three, psyllium has the best evidence (level A) as supported by randomized controlled trials. Bulk-forming agents are in general safe to use, and for them to work properly, adequate fluid intake with the bulk-forming agents is mandatory; otherwise constipation can worsen and bowel obstruction may even ensue. Stool softeners work by its detergent effects. Docusate sodium is the most common agent with a moderate level of evidence (level B). It is often used when bulk-forming agents fail as the first-line agent. Polyethylene glycol (PEG) and lactulose are the common prescribed osmotic agents and they simply increase and retain the water content of the stool. Both have good evidence of use (level A) and lactulose has fewer side effects than PEG, which can cause nausea and diarrhea in the older adults (hence dose titration is needed sometimes). Finally, sennosides and bisacodyl are probably the most commonly prescribed laxatives, which belong to the bowel stimulant group. They act on the myenteric plexus of the colon and enhance peristaltic contractions, stimulating bowel movements. Both have good evidence (level A) of use supported by results from randomized controlled trials. The association of chronic sennosides use with increased risk of colonic cancer remains controversial and unfounded.
What are the considerations for managing constipated elderly patients with OTC products?
In general, for elderly patients, it is advisable to start with oral bulk-forming agents and add in stool softeners as the first step; if results are not satisfactory, one can move up to osmotic agents and finally to bowel stimulants. For the frail older adult patient, it is important to avoid polypharmacy by not using more than two classes of laxatives at the same time. If appropriate, investigations to exclude pelvic floor dysfunction should be done to refine the diagnosis of chronic constipation.
In the past few years, two new classes of agents have been marketed for treating chronic constipation: chloride channel activators and 5-HT4 agonists. How do these new agents work, and how do they compare to the available OTC products?
Chloride channel activators increase intestinal fluids secretion by activating the type 2 chloride channel in the membrane of the gastrointestinal epithelium. So far evidence is good (level A) but known side effects of nausea, headaches, and diarrhea must be considered before prescribing to older adults. In contrast, 5-HT4 agonists act on the 5-HT4 receptors in the myenteric plexus of the bowel and stimulate peristalsis. Evidence of use for 5-HT4 agonists has been tarnished by the recall of the first marketed product (tegaserod) on grounds of increased risk of cardiovascular events. Yet, the next generation product prucalopride has demonstrated a safer cardiovascular profile with particular efficacy in severe cases of constipation. Both agents are more costly than the traditional agents that can be bought over the counter.
When conservative treatment with lifestyle modification and OTC products has failed to adequately manage an older patient’s constipation, what is typically the next course of action?
Physicians should be cognizant of other possible etiologies for chronic constipation when lifestyle modifications and OTC products have failed to bring improvement. A minority of patients with chronic constipation have pelvic floor dysfunction as the cause of constipation and they should be referred to specialists for corrective surgery if appropriate. Also, in extreme cases of chronic constipation leading to bowel obstruction or perforation due to impaction or fecalith formation, surgical treatment will be mandatory as a life-saving measure. Otherwise, specialist management of chronic constipation is rarely necessary.