Chronic constipation: new diagnostic and treatment approaches

Preclinical experimental models for assessing laxative activities of substances/products under investigation: a scoping review of the literature

Constipation is a common gastrointestinal problem worldwide. Its impact on health can range from an unpleasant problem to being seriously troublesome. When lifestyle modification fails to deal with constipation, laxatives are the mainstay of therapy. There are several types of laxatives currently available; however, there still remains a need for better laxatives because certain currently available laxatives are not appropriate for or accessible to some patients. Preclinical experiments to study the laxative potential of substances/products of interest are vital to improving that situation. The selection of appropriate experimental models for assessing the laxative activities of substances/products under investigation is crucial to achieving valid and meaningful results. This article provides a scoping review of the literature, outlining, and summarizing models currently being used in preclinical experiments assessing the laxative activities of substances/products under investigation. The review includes both screening models, e.g., the isolated organ bath system, in vivo fecal assessment and intestinal transit assay, and confirmation models, e.g., in vivo constipation models. Chemical substances/drugs used to induce constipation in in vivo constipation models, e.g., loperamide, diphenoxylate, montmorillonite, and clonidine, as well as standard laxative agents used as a positive control in experimental models, e.g., bisacodyl, carbachol, lactulose, sodium picosulfate, castor oil, phenolphthalein, and yohimbine, are described in detail. The purpose of this article is to assist researchers in the design and implementation of preclinical experimental models for assessing laxative activities of substances/products under investigation to achieve valid and meaningful preclinical results prior to experimentation in humans.

Tegaserod for the Treatment of Irritable Bowel Syndrome

Background: Tegaserod (Zelnorm®) is a 5-hydroxytryptamine (serotonin) type 4 receptor agonist for the treatment of hypomotility disorders of the lower gastrointestinal tract associated with the irritable bowel syndrome with constipation (IBS-C).

Objective: The authors provide the reader with a better understanding on tegaserod mechanism of action, on its pharmacodynamics and pharmacokinetic properties, on safety and tolerability, with a summary of the key published clinical trials conducted in patients with irritable bowel syndrome (IBS). Its effects on colon inflammation have also been described.

Results: Tegaserod was withdrawn in 2007 due to increased risks of cardiovascular adverse effects. The manufacturer denied this, because pre-existing cardiovascular disease or risk factors were attributed to all affected patients. Thus, no causal relationship between tegaserod use and cardiovascular events was clearly shown. A matched case-control study of tegaserod-treated with untreated patients found no association between tegaserod and adverse cardiovascular outcomes. Despite its adverse effects, tegaserod resulted to be effective in treating chronic constipation in adult women aged < 65 years with IBS-C, while the safety and effectiveness of tegaserod in men with IBS-C have not been established.

Conclusion: Tegaserod was resubmitted to the Food and Drug Administration in 2018 for use in a low-risk population. Moreover, tegaserod has also been shown to improve symptoms, enhance gastric accommodation and significantly attenuate visceral pain arising from the colon in functional dyspepsia patients. Treatment with tegaserod seems also to exert a protective effect in inflamed colons, reducing the severity of colitis in animal models.

Review article: diagnosis, management and patient perspectives of the spectrum of constipation disorders

BACKGROUND

Chronic constipation is a common, heterogeneous disorder with multiple symptoms and pathophysiological mechanisms. Patients are often referred to a gastroenterology provider after laxatives fail. However, there is limited knowledge of the spectrum and management of constipation disorders.

AIM

To discuss the latest understanding of the spectrum of constipation disorders, tools for identifying a pathophysiologic-based diagnosis in the specialist setting, treatment options and the patient's perspective of constipation.

METHODS

Literature searches were conducted using PubMed for constipation diagnostic criteria, diagnostic tools and approved treatments. The authors provided insight from their own practices.

RESULTS

Clinical assessment, stool diaries and Rome IV diagnostic criteria can facilitate diagnosis, evaluate severity and distinguish between IBS with constipation, chronic idiopathic constipation and dyssynergic defecation. Novel smartphone applications can help track constipation symptoms. Rectal examinations, anorectal manometry and balloon expulsion, assessments of neuromuscular function with colonic transit time and colonic manometry can provide mechanistic understanding of underlying pathophysiology. Treatments include lifestyle and diet changes, biofeedback therapy and pharmacological agents. Several classes of laxatives, as well as prokinetic and prosecretory agents, are available; here we describe their mechanisms of action, efficacy and side effects.

CONCLUSIONS

Constipation includes multiple overlapping subtypes identifiable using detailed history, current diagnostic tools and smartphone applications. Recognition of individual subtype(s) could pave the way for optimal, evidence-based treatments by a gastroenterology provider.

Current Overview on Clinical Management of Chronic Constipation

Constipation is one of the major gastrointestinal disorders diagnosed in clinical practice in Western countries. Almost 20% of population suffer from this disorder, which means constipation is a substantial utilization of healthcare. Pathophysiology of constipation is complex and multifactorial, where aspects like disturbance in colonic transit, genetic predisposition, lifestyle habits, psychological distress, and many others need to be taken into consideration. Diagnosis of constipation is troublesome and requires thorough accurate examination. A nonpharmacological approach, education of the patient about the importance of lifestyle changes like diet and sport activity state, are the first line of therapy. In case of ineffective treatment, pharmacological treatments such as laxatives, secretagogues, serotonergic agonists, and many other medications should be induced. If pharmacologic treatment fails, the definitive solution for constipation might be surgical approach. Commonness of this disorder, costs of medical care and decrease in quality life cause constipation is a serious issue for many specialists. The aim of this review is to present current knowledge of chronic constipation and management of this disorder.

Comparative efficacy and safety of lactulose plus paraffin vs polyethylene glycol in functional constipation: a randomised clinical study

BACKGROUND

Few head-to-head comparisons of the different classes of laxatives have been conducted.

OBJECTIVE

The objective of this work is to compare the efficacy of lactulose plus paraffin vs polyethylene glycol in the treatment of functional constipation (non-inferiority study).

METHODS

This randomised, parallel-group, multicentre phase 4 study recruited patients with functional constipation diagnosed according to Rome III criteria. Patients received lactulose plus paraffin or polyethylene glycol for 28 days. The primary end point was the change from baseline in the Patient Assessment of Constipation-Symptoms (PAC-SYM) score.

RESULTS

A total of 363 patients were randomised to lactulose plus paraffin (n = 179) or polyethylene glycol (n = 184). On day 28, the mean PAC-SYM score decreased significantly vs baseline with both treatments (p < 0.001). The lower boundary of the 95% CI exceeded the pre-specified limit of -0.25, therefore establishing non-inferiority of lactulose plus paraffin vs polyethylene glycol. At least one adverse event occurred in 20 patients (11.2%) in the lactulose plus paraffin group and in 26 patients (14.2%) in the polyethylene glycol group, most of which were of mild or moderate severity and unrelated to study drugs.

CONCLUSION

Lactulose plus paraffin may be used interchangeably with polyethylene glycol for the pharmacological treatment of functional constipation.Trial registration: EudraCT number 2015-003021-34.

Characterization of gut contractility and microbiota in patients with severe chronic constipation

Chronic constipation (CC) is one of the most common gastrointestinal disorders worldwide. Its pathogenesis, however, remains largely unclear. The purpose of the present work was to gain an insight into the role of contractility and microbiota in the etiology of CC. To this end, we studied spontaneous and evoked contractile activity of descending colon segments from patients that have undergone surgery for refractory forms of CC. The juxta-mucosal microbiota of these colon samples were characterized with culture-based and 16S rRNA sequencing techniques. In patients with CC the spontaneous colonic motility remained unchanged compared to the control group without dysfunction of intestinal motility. Moreover, contractions induced by potassium chloride and carbachol were increased in both circular and longitudinal colonic muscle strips, thus indicating preservation of contractile apparatus and increased sensitivity to cholinergic nerve stimulation in the constipated intestine. In the test group, the gut microbiota composition was assessed as being typically human, with four dominant bacterial phyla, namely Firmicutes, Bacteroidetes, Proteobacteria, and Actinobacteria, as well as usual representation of the most prevalent gut bacterial genera. Yet, significant inter-individual differences were revealed. The phylogenetic diversity of gut microbiota was not affected by age, sex, or colonic anatomy (dolichocolon, megacolon). The abundance of butyrate-producing genera Roseburia, Coprococcus, and Faecalibacterium was low, whereas conventional probiotic genera Lactobacillus and Bifidobacteria were not decreased in the gut microbiomes of the constipated patients. As evidenced by our study, specific microbial biomarkers for constipation state are absent. The results point to a probable role played by the overall gut microbiota at the functional level. To our knowledge, this is the first comprehensive characterization of CC pathogenesis, finding lack of disruption of motor activity of colonic smooth muscle cells and insufficiency of particular members of gut microbiota usually implicated in CC.

A Randomized Double-blind Placebo-controlled Trial on the Effect of Magnesium Oxide in Patients With Chronic Constipation

Background/Aims

Magnesium oxide (MgO) has been frequently used as a treatment for chronic constipation (CC) since the 1980s in Japan. The aim of this study is to evaluate its therapeutic effects of MgO in Japanese CC patients.

Methods

We conducted a randomized, double-blind placebo-controlled study. Thirty-four female patients with mild to moderate constipation were randomly assigned to either placebo (n = 17) or MgO group (n = 17) 0.5 g × 3/day for 28 days. Primary endpoint was overall improvement over the 4-week study period. Secondary endpoints were changes from baseline in spontaneous bowel movement (SBM), response rates of complete spontaneous bowel movement (CSBM), stool form, colonic transit time (CTT), abdominal symptom, and quality of life.

Results

One patient failed to complete the medication regimen and was omitted from analysis: data from 16 placebo and 17 MgO patients were analyzed. The primary endpoint was met by 25.0% of placebo vs 70.6% of MgO group (P = 0.015). MgO significantly improved SBM changes compared to placebo (P = 0.002). However, MgO did not significantly improved response rates of CSBM compared to placebo (P = 0.76). In addition, MgO significantly improved Bristol stool form scale changes (P < 0.001) and significantly improved CTT compared to the placebo group (P < 0.001). MgO significantly improved the Japanese version of the patient assessment of constipation quality of life (P = 0.003).

Conclusion

Our placebo-controlled study demonstrated that MgO was effective treatment for improving defecation status and shortened CTT in Japanese CC patients with mild to moderate symptoms.

Constipation in children: Diagnosis, treatment, and prevention

Deviation from normal bowel function in the pediatric population is often a cause for concern for parents and caregivers, prompting numerous visits to a primary care provider. Constipation is a common and challenging issue in children that can have an adverse impact on their psychosocial and emotional well-being as well as quality of life. This article provides practical strategies for diagnosing, treating, and preventing constipation in children.

Radiographic stool quantification: an equivalence study of 484 symptomatic and asymptomatic subjects

PURPOSE

To determine if symptomatic patients referred for radiographic stool quantification have equivalent stool burden to asymptomatic patients.

METHOD

This was an IRB-approved HIPAA-compliant retrospective equivalence cohort study. An a priori equivalence power calculation was performed. Consecutive abdominal radiographs performed in adult outpatients with bloating, constipation, diarrhea, or abdominal pain to assess "fecal loading" [n = 242 (fecal cohort)] were compared to those performed in asymptomatic adult outpatients to assess "renal stones" [n = 242 (renal cohort)]. Radiographs were randomized and reviewed by two blinded independent abdominal radiologists. Exclusion criteria, designed to avoid unblinding, included urinary tract calculi ≥ 0.5 cm, multiple urinary tract calculi, and ureteral stent(s). Readers scored all radiographs (n = 484) for stool burden using validated Leech criteria [scale: 0 (none) to 15 (extreme diffuse)]. Mean Leech scores and 95% confidence intervals were calculated. Multivariable generalized linear modeling was performed to adjust for baseline medication use, age, and gender. The adjusted parameter estimate was used to test for equivalence in the mean difference between cohorts using Schuirmann's method of two one-sided t-tests. Inter-reader agreement was assessed with intraclass correlation coefficients.

RESULTS

Overall mean Leech scores for fecal [6.9 (95% CI 6.7, 7.2)] and renal [7.3 (95% CI 7.1, 7.5)] cohorts were equivalent within a margin of 0.75 (adjusted mean difference: - 0.4 [90% CI - 0.7, - 0.04]; p value = 0.02). Inter-reader agreement was good [ICC: 0.62 (95% CI 0.56, 0.68)].

CONCLUSION

Radiographic stool quantification produces equivalent results in symptomatic and asymptomatic adults and is of uncertain value.

Regulation of gastrointestinal hormones during laxative activity of gallotannin-enriched extract isolated from Galla Rhois in loperamide-induced constipation of SD rats

Regulation of gastrointestinal hormones have been reported in animal models for constipation undergoing laxative therapy when administered herbal products. We undertook to investigate whether the laxative activity of gallotannin-enriched extracts isolated from Galla Rhois (GEGR) affects the regulation of gastrointestinal hormones, by examining the concentration of four hormones and the activation of their receptors in the loperamide (Lop)-induced constipation model. Stool parameters, including number, weight and water content, were significantly recovered in the Lop+GEGR treated group, relative to the Lop+vehicle treated group; however, food intake and water consumption were maintained at a constant level. Also, a similar recovery was detected for thickness of mucosa, muscle and flat luminal surface in the Lop+GEGR treated group. Furthermore, concentration of the four gastrointestinal hormones evaluated, namely, cholecystokinin (CCK), gastrin (GAS), somatostatin (SS) and motilin (MTL), were lower in the Lop+vehicle treated group than the No treated group, but were remarkably enhanced in the Lop+GEGR treated group. Moreover, the downstream signaling pathway of MTL and SS receptors were recovered after GEGR administration. Results of the present study therefore indicate that the laxative effects of GEGR treatment may be tightly related with the regulation of gastrointestinal hormones in the Lop-induced constipation model.

Factors predictive of treatment-emergent adverse events of prucalopride: an integrated analysis of four randomized, double-blind, placebo-controlled trials

Background/Aims

This integrated analysis aimed to identify the factors associated with the most frequently reported treatment-emergent adverse events (TEAEs) in Asian and non-Asian patients with chronic constipation (CC) who receive prucalopride or placebo over 12 weeks.

Methods

Pooled data from four randomized, double-blind, placebo-controlled, multicenter, phase III studies (NCT00488137, NCT00483886, NCT00485940, and NCT01116206) on patients treated with prucalopride 2 mg or placebo were analyzed. The associations between predictors and TEAEs were evaluated based on a logistic regression model.

Results

Overall, 1,821 patients (Asian, 26.1%; non-Asian, 73.9%) were analyzed. Prucalopride treatment was significantly associated with diarrhea, headache, and nausea (p<0.001), but not with abdominal pain, compared with placebo. Differences in the prevalence of TEAEs between prucalopride and placebo decreased greatly after the first day of treatment. Compared with non-Asians, Asians were more likely to experience diarrhea and less likely to develop abdominal pain, headache, and nausea. Prior laxative use, CC duration, and body weight were not predictive of any of these TEAEs.

Conclusions

Prucalopride treatment was positively associated with diarrhea, headache, and nausea. Asian patients tended to have a higher frequency of diarrhea but lower frequencies of headache, abdominal pain, and nausea compared with non-Asians.

Chronic constipation in the elderly: a primer for the gastroenterologist

Constipation is a frequently reported bowel symptom in the elderly with considerable impact on quality of life and health expenses. Disease-related morbidity and even mortality have been reported in the affected frail elderly. Although constipation is not a physiologic consequence of normal aging, decreased mobility, medications, underlying diseases, and rectal sensory-motor dysfunction may all contribute to its increased prevalence in older adults. In the elderly there is usually more than one etiologic mechanism, requiring a multifactorial treatment approach. The majority of patients would respond to diet and lifestyle modifications reinforced by bowel training measures. In those not responding to conservative treatment, the approach needs to be tailored addressing all comorbid conditions. In the adult population, the management of constipation continues to evolve as well as the understanding of its complex etiology. However, the constipated elderly have been left behind while gastroenterology consultations for this common conditions are at a rise for the worldwide age increment. Aim of this review is to provide an update on epidemiology, quality of life burden, etiology, diagnosis, current approaches and limitations in the management of constipation in the older ones to ease the gastroenterologists’ clinic workload.

Effect of Connective Tissue Manipulation on Symptoms and Quality of Life in Patients With Chronic Constipation: A Randomized Controlled Trial

OBJECTIVE

The purpose of this study was to examine the effects of connective tissue manipulation (CTM) on the severity of constipation and health-related quality of life in individuals diagnosed with chronic constipation.

METHODS

Fifty patients with a diagnosis of chronic constipation according to Rome III criteria were recruited and randomized to an intervention (n = 25) or control group (n = 25). The intervention group received CTM in addition to the lifestyle advice, whereas the control group was given only lifestyle advice for constipation. All assessments were performed at baseline and at the end of 4 weeks. The primary outcome measure was the Constipation Severity Instrument. Secondary outcomes included Patient Assessment of Constipation Quality of Life Questionnaire, Bristol Stool Scale, and 7-day bowel diary. Differences between groups were analyzed with t tests, Mann-Whitney U test and χ(2) test.

RESULTS

Compared with the control group, subjects in the intervention group reported significantly greater improvement in total and subscale scores of the Constipation Severity Instrument and Patient Assessment of Constipation Quality of Life Questionnaire (P < .05). Based on the results from bowel diaries, the improvements in the number of bowel movements, duration of defecation, stool consistency, and the feeling of incomplete evacuation in the intervention group were also significantly more than the control group (P < .05).

CONCLUSION

This study showed that CTM and lifestyle advice were superior to reducing symptoms of constipation and quality of life compared with lifestyle advice alone for patients with chronic constipation.

Chronic severe constipation: current pathophysiological aspects, new diagnostic approaches, and therapeutic options

Chronic constipation is a considerable problem because it significantly affects the quality of a patient's life. Constipation can be diagnosed at every age and is more frequent in women and among the elderly. In epidemiological studies, its incidence is estimated at 2-27% in the general population. Chronic constipation may be primary or secondary. However, primary constipation (functional or idiopathic) can be classified into normal transit constipation, slow transit constipation, and pelvic outlet obstruction. In this review we make an attempt to present the current pathophysiological aspects and new therapeutic options for chronic idiopathic constipation, particularly highlighting the value of patient assessment for accurate diagnosis of the cause of the problem, thus helping in the choice of appropriate treatment.

Effect of Prucalopride in the Treatment of Chronic Constipation in Asian and Non-Asian Women: A Pooled Analysis of 4 Randomized, Placebo-controlled Studies

Background/Aims

To compare the efficacy and safety of prucalopride, a novel selective high-affinity 5-hydroxytryptamine type 4 receptor agonist, versus placebo, in Asian and non-Asian women with chronic constipation (CC).

Methods

Data of patients with CC, receiving once-daily prucalopride 2-mg or placebo for 12-weeks, were pooled from 4 double-blind, randomized, phase-III trials (NCT00488137, NCT00483886, NCT00485940 and NCT01116206). The efficacy endpoints were: average of ≥ 3 spontaneous complete bowel movements (SCBMs)/week; average increases of ≥ 1 SCBMs/week; and change from baseline in each CC-associated symptom scores (bloating, abdominal pain, hard stool and straining).

Results

Overall, 1,596 women (Asian [26.6%], non-Asian [73.4%]) were included in this analysis. Significantly more patients in the prucalopride group versus placebo experienced an average of ≥ 3 SCBMs/week in Asian (34% vs. 11%, P < 0.001) and non-Asian (24.6% vs. 10.6%, P < 0.001) subgroups. The number of patients reporting an increase of ≥ 1 SCBMs/week from baseline was significantly higher in the prucalopride group versus placebo among both Asian (57.4% vs. 28.3%, P < 0.001) and non-Asian (45.3% vs. 24.0%, P < 0.001) subgroups. The difference between the subgroups was not statistically significant. Prucalopride significantly reduced the symptom scores for bloating, hard stool, and straining in both subgroups.

Conclusions

Prucalopride 2-mg once-daily treatment over 12-weeks was more efficacious than placebo in promoting SCBMs and improvement of CC-associated symptoms in Asian and non-Asian women, and was found to be safe and well-tolerated. There were numeric differences between Asian and non-Asian patients on efficacy and treatment emergent adverse events, which may be partially due to the overlap with functional gastrointestinal disorders in non-Asian patients.

Advances in the management of constipation-predominant irritable bowel syndrome: the role of linaclotide

Constipation-predominant irritable bowel syndrome (IBS-C) is a commonly prevalent and clinically challenging disorder to treat. Until recently, most therapeutic agents had limited ability to address the complexity of symptoms inherent to the syndrome. The development of linaclotide provides a physiologically sound approach to treatment of the multiple symptoms of IBS-C. Clinical trials demonstrate the efficacy of linaclotide, and a platform to better understand the symptomatology of IBS-C. Based on recent clinical evidence, linaclotide should be considered for patients with IBS-C because it improves abdominal pain and bowel symptoms. In phase III trials, linaclotide met the US Food and Drug Administration responder endpoint with a number needed to treat (NNT) of 5.1-7.9, and European Medicines Agency coprimary endpoints at 12 weeks with a NNT of 4.39-7.69, and at 26 weeks with a NNT of 4.93-5.68. It is safe and effective, with diarrhea reported as the most common adverse effect, which leads to discontinuation of the medication in approximately 5% of patients.

Prucalopride: a review of its use in the management of chronic constipation

The highly selective serotonin 5-HT4 receptor agonist prucalopride (Resolor(®), Resotran(®), Resotrans(®)) is indicated for the treatment of chronic constipation. In four randomized, double-blind, multicentre, 12-week trials in patients (predominantly women) with chronic constipation, oral prucalopride 2 mg once daily improved bowel function to a significantly greater extent than placebo, with a significantly greater proportion of prucalopride than placebo recipients achieving an average of ≥3 spontaneous, complete bowel movements per week (primary endpoint). Significantly greater improvements in health-related quality of life, patient satisfaction with treatment and bowel habit, and a range of constipation-related symptoms were also seen with prucalopride than with placebo. Satisfaction with treatment and bowel habit was maintained with prucalopride in the longer term. Prucalopride was generally well tolerated in patients with chronic constipation, with the most commonly reported adverse events (headache, nausea, abdominal pain, diarrhoea) primarily occurring on the first day of treatment. During the clinical trials, no cardiovascular safety issues have arisen in patients with chronic constipation receiving prucalopride. In conclusion, prucalopride is an important option for use in patients with chronic constipation who have not experienced adequate relief with laxatives.

Factors affecting satisfaction with treatment in European women with chronic constipation: An internet survey

BACKGROUND

Data on factors affecting treatment satisfaction in European women with chronic constipation are limited.

OBJECTIVE

To assess factors associated with treatment satisfaction among European women with chronic constipation.

METHODS

A 2011-2012 internet survey was conducted in men and women from 12 European countries. Respondents analysed were female with self-reported chronic constipation (≥1 symptoms for ≥6 months of lumpy/hard stools, feeling of incomplete evacuation, and pain during defecation, as well as <3 bowel movements/week). For laxative users, satisfaction with treatment, factors affecting satisfaction, and interactions with healthcare professionals were collected.

RESULTS AND CONCLUSIONS

In total, 4805/50,319 participants fulfilled the inclusion criteria (female with chronic constipation). Of the laxative users (1575/4805), 57% (n = 896) were satisfied with their treatment, while 26% were neutral, and 17% dissatisfied. Dissatisfied respondents visited their GP less frequently in the past 12 months, were more likely to obtain over-the-counter laxatives, and took a dose higher than recommended more frequently than those satisfied. Respondents were most satisfied with ease of use of treatment and least satisfied with relief from bloating. Newer treatments aimed at alleviating symptoms, particularly bloating, are required for respondents neutral or dissatisfied with their current treatment.

Chronic constipation and treatment options (Review)

Chronic constipation (CC) is a highly prevalent heterogeneous disorder. Although CC is not known to be associated with the development of serious disease or with excess mortality, it considerably reduces the patients quality of life. In addition, it represents an economic burden to patients and society. The majority of patients with CC successfully manage the disorder by dietary management and the use of laxatives. Patients with functional CC (slow‑transit and non‑slow transit constipation) do not respond to laxatives and are a small fraction of the total population complaining of constipation. Regardless of the low number of these patients, the intractability of their symptoms causes psychological and social stress and greatly impairs their quality of life. Furthermore, these patients consume a disproportionate quantity of medical resources. It appears that these patients have a disturbance in the serotonin transmission system, which results in a cascade of alterations in a number of gut neuroendocrine hormones/transmitters. The effect of prucalopride, a serotonin receptor agonist, in this category of patients appears to be not only a pharmacological prokinetic action, but also a correction of a pre‑existing disturbance. Linaclotide, a member of the guanylin peptide family, binds to the ligand‑binding region of guanylate cyclase‑C on the luminal surface of gastrointestinal epithelia resulting in increased fluid secretion. This drug has also been found to be effective for the treatment of functional CC. In addition, biofeedback and sacral nerve stimulation are effective in the treatment of CC caused by pelvic floor disorders.

Constella™(EU)-Linzess™(USA): the last milestone in the long journey of the peptide linaclotide and its implications for the future of peptide drugs

Irritable bowel syndrome with constipation (IBS-C) and chronic idiopathic constipation (CIC) are highly prevalent gastrointestinal disorders associated with health, economical and social problems. Recently, after a long journey of preclinical studies and clinical trials, linaclotide, a first-in-class GC-C receptor peptide agonist, has received the approval in the USA and Europe for the treatment of IBS-C and CIC. This article provides an overview of clinical, economic and biological aspects of IBS-C and CIC and covers the current and emerging therapeutic agents for treating these conditions. Particularly, the pharmacodynamic and pharmacokinetic properties of linaclotide, a small, disulfide-rich peptide, and its implications in the future of peptide drug discovery and development are discussed.