Brenner, Darren M.

Myths and misconceptions about the evaluation and treatment of constipation persist. Many widely prevalent misconceptions about laxatives, specifically stimulant laxatives, interfere with the effective management of constipation. Although some of these myths and misconceptions have been dispelled in recent years, there is additional room for improving the awareness and understanding of the pathophysiology of constipation, the mechanisms of action and the efficacy and safety of available therapies. An evolution in our understanding of pathophysiology and the availability of new treatments requires that primary care practitioners be better positioned to treat this common disorder that reduces patients’ quality of life and negatively impacts the healthcare system. This review defines constipation and elucidates various factors that contribute to its aetiology, including lifestyle, dietary habits, medications and underlying medical conditions. This review addresses and refutes common myths and misconceptions about constipation, such as the belief that regular bowel movements must occur daily or the use of laxatives leads to dependence. This review also highlights the importance of distinguishing between normal and abnormal bowel habits and emphasises the need for individualised management approaches to address constipation effectively. Finally, the review discusses different classes of laxatives, dispelling misconceptions about their safety, efficacy and potential for misuse, with a specific focus on stimulant laxatives. In summary, this review enhances awareness and knowledge of this prevalent disorder, provides evidence-based insights into common myths and misconceptions surrounding constipation and promotes more informed decision-making regarding constipation and the use of laxatives.

INTRODUCTION: This post hoc analysis evaluated the efficacy of tenapanor on abdominal symptoms in patients with irritable bowel syndrome with constipation. Abdominal symptoms assessed included pain, discomfort, bloating, cramping, and fullness. METHODS: The abdominal symptom data were pooled from 3 randomized controlled trials (NCT01923428, T3MPO-1 [NCT02621892], and T3MPO-2 [NCT02686138]). Weekly scores were calculated for each abdominal symptom, and the Abdominal Score (AS) was derived as the average of weekly scores for abdominal pain, discomfort, and bloating. The overall change from baseline during the 12 weeks was assessed for each symptom weekly score and the AS. The AS 6/12-week and 9/12-week response rates (AS improvement of ≥2 points for ≥6/12- or ≥9/12-week) were also evaluated. The association of weekly AS response status (reduction of ≥30%) with weekly complete spontaneous bowel movement (CSBM) status (=0 and >0) was assessed. RESULTS: Among 1,372 patients (684 tenapanor [50 mg twice a day] and 688 placebo), the least squares mean change from baseline in AS was −2.66 for tenapanor vs −2.09 for placebo ( P < 0.0001). The 6/12-week AS response rate was 44.4% for tenapanor vs 32.4% for placebo ( P < 0.0001), and for 9/12-week AS, 30.6% for tenapanor vs 20.5% for placebo ( P < 0.0001). A significant association between weekly CSBM status and weekly AS response status was observed each week ( P < 0.0001), with a greater proportion achieving an AS reduction in patients with >0 CSBMs in a week. DISCUSSION: Tenapanor significantly reduced abdominal symptoms in patients with irritable bowel syndrome with constipation, particularly pain, discomfort, and bloating measured by AS, compared with placebo.

INTRODUCTION: These post hoc analyses provide clinically relevant data concerning time to response for individual irritable bowel syndrome with constipation (IBS-C) symptoms after linaclotide use. METHODS: Time-to-response data were pooled from 4 randomized controlled trials. Response time for abdominal symptoms (pain, discomfort, and bloating) and complete spontaneous bowel movements (CSBMs) were analyzed using the Kaplan-Meier method; patients were categorized as early responders (≤4 weeks), late responders (>4–12 weeks), or nonresponders. RESULTS: Among 2,350 patients (1,172 placebo and 1,178 linaclotide 290 μg), >50% of patients with IBS-C who initiated linaclotide treatment experienced a decrease of ≥30% in abdominal pain, discomfort, or bloating within 3–4 weeks (median). The median time to achieving ≥3 CSBMs was 4 weeks. Although not all linaclotide-treated patients responded within 12 weeks, a late response occurred between 4 and 12 weeks in 1 in 6 patients for abdominal pain and in approximately 1 in 10 patients for CSBM frequency. Comparisons of early responders, late responders, and nonresponders for both response definitions indicated that women, Whites, and patients with less severe baseline abdominal symptoms were more likely to respond early. DISCUSSION: Although treatment responses with linaclotide occurred in >50% of patients with IBS-C within 4 weeks of treatment initiation, benefits for individual abdominal symptoms and/or CSBM frequency can still occur between 4 and 12 weeks. A lack of improvement in one symptom does not negate the possibility of response for others, highlighting the importance of discussing all symptoms with patients and not assuming treatment futility at 4 weeks.

Chronic idiopathic constipation and irritable bowel syndrome with constipation are complex, overlapping conditions. Although multiple guidelines have informed healthcare providers on appropriate treatment options for patients with chronic idiopathic constipation and irritable bowel syndrome with constipation, little direction is offered on treatment selection. First-line treatment options usually include fiber and over-the-counter osmotic laxatives; however, these are insufficient for many individuals. When these options fail, prescription secretagogues (plecanatide, linaclotide, lubiprostone, and tenapanor [pending commercial availability]), or serotonergic agents (prucalopride and tegaserod) are generally preferred. Individuals experiencing concurrent abdominal pain and/or bloating may experience greater overall improvements from prescription therapies because these agents have been proven to reduce concurrent abdominal and bowel symptoms. Should initial prescription treatments fail, retrying past treatment options (if not adequately trialed initially), combining agents from alternative classes, or use of adjunctive therapies may be considered. Given the broad spectrum of available agents, therapy should be tailored by mutual decision-making between the patient and practitioner. Overall, patients need to be actively monitored and managed to maximize clinical outcomes.

INTRODUCTION: Tegaserod was the first US Food and Drug Administration–approved drug for irritable bowel syndrome with constipation (IBS-C) in women and was recently reapproved for use. Recognizing that clinical trials were performed almost 20 years ago, we performed an integrated analysis on patient-reported outcomes relevant to current practice including previously unpublished data. METHODS: Data from 4 12-week, randomized, placebo-controlled trials evaluating tegaserod 6 mg b.i.d. in patients with IBS-C were pooled. We analyzed 2 groups: all women (overall population) and women younger than 65 years without a history of cardiovascular ischemic events (indicated population). The primary end point was subjective global assessment of IBS-C symptom relief. Responders rated themselves as “considerably” or “completely” relieved ≥50% of the time or at least “somewhat relieved” 100% of the time over the last 4 weeks. RESULTS: The overall and indicated populations included 2,939 (tegaserod [n = 1,478]; placebo [n = 1,461]) and 2,752 (tegaserod [n = 1,386]; placebo [n = 1,366]) participants, respectively. The pooled odds ratios (95% confidence interval) for clinical response during the last 4 weeks in the overall and indicated populations with tegaserod were 1.37 (1.18, 1.59; P < 0.001) and 1.38 (1.18, 1.61; P < 0.001). In the overall and indicated populations, clinical response rates for tegaserod during the last 4 weeks were 43.3% and 44.1% versus 35.9% and 36.5% with placebo ( P < 0.001). Adverse events were similar between groups. No significant cardiovascular events related to tegaserod were observed in patients with ≤1 cardiac risk factor. DISCUSSION: Tegaserod 6 mg b.i.d. reduced IBS-C symptoms in overall and US Food and Drug Administration–indicated populations (women aged <65 years with no history of cardiovascular ischemic events).

Chronic abdominal pain is a common gastrointestinal (GI) symptom that characterizes many functional GI disorders/disorders of gut-brain interaction, including irritable bowel syndrome, functional dyspepsia, and centrally mediated abdominal pain syndrome. The symptoms of abdominal pain in these highly prevalent disorders are often treated with antispasmodic agents. Antispasmodic treatment includes a broad range of therapeutic classes with different mechanisms of action, including anticholinergic/antimuscarinic agents (inhibition of GI smooth muscle contraction), calcium channel inhibitors (inhibition of calcium transport into GI smooth muscle), and direct smooth muscle relaxants (inhibition of sodium and calcium transport). The aim of this review article was to examine the efficacy and safety of antispasmodics available in North America (e.g., alverine, dicyclomine, hyoscine, hyoscyamine, mebeverine, otilonium, pinaverium, and trimebutine) for the treatment of chronic abdominal pain in patients with common disorders of gut-brain interaction. For the agents examined, comparisons of studies are limited by inconsistencies in treatment dosing and duration, patient profiles, and diagnostic criteria employed. Furthermore, variability in study end points limits comparisons. Risk of selection, performance, detection, attrition, and reporting bias also differed among studies, and in many cases, risks were considered “unclear.” The antispasmodics evaluated in this review, which differ in geographic availability, were found to vary dramatically in efficacy and safety. Given these caveats, each agent should be considered on an individual basis, rather than prescribed based on information across the broad class of agents.