Chronic constipation: Let symptom type and severity direct treatment
How various therapies fit into the scheme of things; what is unlikely to help.
- Increased fiber intake through diet (C) or fiber supplements (B) is an appropriate initial therapy for chronic constipation.
- Osmotic and stimulant laxatives may be administered to patients who do not respond to more conservative measures if the limitations of these agents are explained (B).
- Tegaserod, a selective 5-hydroxytryptamine type 4 (5-HT4) receptor partial agonist, is more effective than placebo at relieving symptoms of chronic idiopathic constipation in patients younger than 65 years of age (A).
- Patients with suspected defecation disorders and those with treatment-refractory symptoms should be referred to a gastroenterologist for further evaluation (C).
By the time a patient sees you with a complaint of constipation, chances are she has tried a remedy or 2 and is now looking for something new. However, the abandoned remedies may yet prove useful, depending on the nature of her complaint and on her understanding of how the remedy was supposed to have worked. In this article, we discuss the benefits and limitations of several treatment options in managing a patient’s distinct condition, as assessed in part 1 (page 580).
Symptom-focused treatment
As per the ACG Task Force guidelines, initial treatment of chronic constipation (in the absence of alarm features and secondary causes) is empiric.1 The patient’s symptoms—specifically those most bother-some—should direct your decisions. A plan so guided will also help you manage the patient’s expectations.
Address patients’ prior disappointments
Most patients will have self-treated before coming to see you, and some even will have tried prescribed regimens. Initial treatment of constipation has traditionally involved lifestyle changes (eg, diet, fluid, exercise modification), increased fiber intake, and laxatives. However, evidence supporting use of these modalities in this setting is sparse, and patient surveys often show dissatisfaction with these approaches. For instance, a web-based survey showed that 96% of patients with chronic constipation have tried some form of traditional medication (eg, bulking agents, stool softeners, laxatives).2 Overall, 47% were not satisfied with their current treatment, primarily because of inadequate symptom relief and unwanted side effects.
Furthermore, patient compliance with some therapies is poor because of side effects such as flatulence, distension, and bloating. Two recently published systematic reviews evaluating treatment options for patients with chronic constipation came to similar conclusions.1,3
Below we discuss the ACG Chronic Constipation Task Force conclusions and recommendations.1 Explicit communication with patients about what they can expect will help ensure treatment success.
Prescribe fiber, increase water intake
Just a few clinical trials have evaluated the effects of lifestyle changes on constipation symptoms, and they have generally been poorly designed or involved small numbers of patients (TABLE).4-7
Educating patients about proper nutrition and designating a time for daily defecation are common initial approaches, but efficacy of these strategies in this patient population has not been established (SOR: C).4,5
Exercise has dubious value. Exercise is often recommended as a way to treat constipation because of its purported effect on reducing gastrointestinal (GI) transit time (SOR: C).6 However, uncontrolled studies have found that aerobic exercise does not necessarily decrease transit time and may actually prolong it.6
Increasing water alone generally unhelpful… Few data support the benefits of increased fluid consumption, except for dehydrated patients. In one study, increased intake (to 1 L/d) of water or isotonic fluid had no effect on the stool weight of healthy volunteers.4
…but fiber plus water works. However, in a study involving patients with chronic constipation, a high-fiber diet and 2 L/d of water increased frequency of bowel movements and reduced use of laxatives compared with the same diet and ad libitum fluid intake (P<.001). By binding water, fiber increases stool weight, softens stool, decreases colonic transit time, and increases GI motility.4,5,8,9
You can recommend that patients gradually increase fiber intake over several weeks to a total of 20 g/d to 25 g/d)18 through fiber-rich foods (vegetables [eg, carrots, broccoli, string beans], fruits [eg, peaches, apples, oranges], whole-grain breads, pasta, cereal, etc) (SOR: C) or bulk supplements (eg, psyllium, methylcellulose, and polycarbophil) (SOR: B). In conjunction with other lifestyle modifications, this is a reasonable management decision.11 Because failure to balance the ratio between fiber and fluid can worsen constipation, and even cause intestinal obstruction, tell patients who increase their fiber consumption to also increase their fluid intake (30 mL/kg body weight daily).5,12
Caveats. Few data support the benefits of this approach. Epidemiologic studies show a low prevalence of constipation in countries in which fiber-rich diets are the norm,8 but extrapolating data from healthy populations to constipated patients may not be justified.13 In fact, few data from controlled trials support the use of fiber therapy in patients with constipation. In the uncontrolled Nurses’ Health Study, subjects in the highest quintile of dietary fiber intake (median intake, 20 g/d) were less likely to have constipation than those in the lowest quintile (median intake, 7 g/d).14 This general dearth of evidence led the ACG Chronic Constipation Task Force to conclude that psyllium increases stool frequency in patients with chronic constipation (ACG grade: B) but that there are insufficient data to make a recommendation about the efficacy of calcium polycarbophil, methylcellulose, and bran in this patient population (ACG grade: B).1
