A blind, randomized comparison of racecadotril and loperamide for stopping acute diarrhea in adults

Racecadotril Versus Loperamide in Acute Radiation Enteritis: A Randomized, Double-Masked, Phase 3, Noninferiority Trial

PURPOSE

There is currently no gold standard for the management of acute radiation enteritis. We compared the efficacy and safety of Racecadotril, an anti-hypersecretory drug, versus Loperamide, an anti-motility agent, in acute radiation enteritis.

METHODS AND MATERIALS

We conducted a randomized, double-masked, non-inferiority trial at a single research institute. Patients receiving curative radiation for pelvic malignancies, who developed grade 2 or 3 diarrhea (as per Common Terminology Criteria for Adverse Events, v 4.0) were included in the study. Patients in the intervention arm received Racecadotril and placebo. Patients in the control arm received Loperamide and placebo. The primary outcome was the resolution of diarrhea, 48 hours after the start of treatment.

RESULTS

162 patients were randomized between 2019 and 2022. On intention-to-treat analysis, 68/81 patients, 84%, (95% CI, 74.1%-91.2%) in the Racecadotril arm and 70/81, 86.4%, (95% CI, 77.0%-93.0%) in the Loperamide arm improved from grade 2 or 3 diarrhea to grade 1 or 0, (P= .66, χ2 test). The difference in proportion was 2.4% (95% CI: -8.5% to 13.4%). Since the upper boundary of the 95% CI crossed our non-inferiority margin of 10% (13.4%) we could not prove the non-inferiority of Racecadotril over Loperamide. Rebound constipation was more in the Loperamide arm compared to Racecadotril (17.3% vs 6.2%; P = .028) CONCLUSIONS: The non-inferiority of Racecadotril to Loperamide in acute radiation enteritis could not be demonstrated. However, Racecadotril can be the preferred drug of choice in acute radiation enteritis because Racecadotril does not affect bowel motility, achieved a high clinical success rate similar to that of Loperamide, and was associated with lesser side effects.

Alpha Ketoglutarate Downregulates the Neutral Endopeptidase and Enhances the Growth Inhibitory Activity of Thiorphan in Highly Aggressive Osteosarcoma Cells

Since natural substances are widely explored as epigenetic modulators of gene expression and epigenetic abnormalities are important causes of cancerogenesis, factors with pro-tumor activities subjected to epigenetic control, e.g., neutral endopeptidase (NEP, neprilysin), are promising anticancer targets for potential therapies acting via epigenetic regulation of gene expression. Alpha-ketoglutarate (AKG) is a naturally occurring co-substrate for enzymes involved in histone and DNA demethylation with suggested anti-cancer activity. Hence, we investigated a potential effect of AKG on the NEP expression in cells derived from various cancers (cervical, colon, osteosarcoma) and normal epithelial cells and osteoblasts. Moreover, the overall methylation status of histone H3 was explored to establish the molecular target of AKG activity. Additionally, it was investigated whether AKG in combination with thiorphan (NEP specific inhibitor) exhibited enhanced anticancer activity. The results revealed that AKG downregulated the expression of NEP at the protein level only in highly aggressive osteosarcoma HOS cells (flow cytometry and fluorometric assays), and this protease was found to be involved in AKG-induced growth inhibition in osteosarcoma cells (siRNA NEP silencing, BrdU assay, flow cytometry). Unexpectedly, AKG-induced hypermethylation of H3K27 in HOS cells, which was partially dependent on EZH2 activity. However, this effect was not implicated in the AKG-induced NEP downregulation (flow cytometry). Finally, the combined treatment with AKG and thiorphan was shown to significantly enhance the growth inhibitory potential of each one towards HOS cells (BrdU assay). These preliminary studies have shown for the first time that the downregulation of NEP expression is a promising target in therapies of NEP-implicating HOS cells. Moreover, this therapeutic goal can be achieved via AKG-induced downregulation of NEP and synergistic activity of AKG with thiorphan, i.e., a NEP specific inhibitor. Furthermore, this study has reported for the first time that exogenous AKG can influence the activity of histone methyltransferase, EZH2. However, this issue needs further investigation to elucidate the mechanisms of this phenomenon.

Diarrhoea Management using Over-the-counter Nutraceuticals in Daily practice (DIAMOND): a feasibility RCT on alternative therapy to reduce antibiotic use

BACKGROUND

Although rarely indicated, antibiotics are commonly used for acute diarrhoea in China. We conducted a randomised, double blind exploratory clinical trial of loperamide, berberine and turmeric for treatment of acute diarrhoea.

METHODS

Adults with acute uncomplicated diarrhoea aged 18 to 70 were randomised to 4 groups: (A) loperamide; (B) loperamide and berberine; (C) loperamide and turmeric; (D) loperamide, berberine and turmeric. All participants were given rescue ciprofloxacin for use after 48 h if symptoms worsened or were unimproved. Primary endpoints were feasibility and ciprofloxacin use during the 2-week follow-up period. Semi-structured interviews were conducted following recruitment and were analysed thematically. Recruiting doctors, delivery pharmacists and research assistants were blinded to treatment allocation.

RESULTS

Only 21.5% (278/1295) of patients screened were deemed eligible, and 49% (136/278) of these consented and were entered into the final analysis. Most participants had mild symptoms, because most patients with moderate or severe symptoms wanted to be given antibiotics. Follow-up was good (94% at 2 weeks). Only three participants used rescue antibiotics compared to 67% of acute diarrhoea patients in the hospital during the recruitment period. The median symptom duration was 14 h in group B (interquartile range (IQR) 10-22), 16 h in group D (IQR 10-22), 18 h in group A (IQR 10-33) and 20 h in group C (IQR 16-54). Re-consultation rates were low. There were no serious treatment-related adverse events. Most interviewed participants said that although they had believed antibiotics to be effective for diarrhoea, they were surprised by their quick recovery without antibiotics in this trial.

CONCLUSION

Although recruitment was challenging because of widespread expectations for antibiotics, patients with mild diarrhoea accepted trying an alternative. The three nutraceuticals therapy require further evaluation in a fully powered, randomised controlled trial among a broader sample.

TRIAL REGISTRATION

ChiCTR-IPR-17014107.

Diarrhea as a Clinical Challenge: General Practitioner Approach

BACKGROUND

Diarrhea is defined as the passage of loose stools and increase in stool frequency, weight, or volume. Diarrhea is an important health issue since it accounts for 2.5 million deaths in the world each year.

SUMMARY

Diarrhea can be acute, persistent, or chronic. Acute diarrhea (AD) is usually infectious, caused by viruses, less frequently by bacteria and parasites. The majority of cases of AD are self-limiting and do not require diagnostic workup. The use of diagnostic tests in AD should be limited to patients with signs of severe dehydration, bloody stools, persistent fever and those suffering from immunodeficiencies using immunosuppressive therapy or to cases of suspected nosocomial infection. These patients should be referred to gastroenterologists or infectious disease specialists. Therapy in AD consists of early oral refeeding, antidiarrheal medications, antibiotics, and probiotics. Chronic diarrhea (CD) has diverse etiology. The majority of patients have self-limiting symptoms or functional gastrointestinal disorders. Patients with blood in stool, weight loss, clinical and laboratory signs of anemia, and palpable mass in the abdomen (red flag symptoms) need urgent gastroenterology referral. Therapy in CD is possible when the underlying cause of symptoms is identified.

KEY MESSAGES

The general practitioner should identify high-risk patients with AD and/or red flag symptoms for urgent gastroenterology referral.

Epidermal growth factor receptor inhibitor-induced diarrhea: clinical incidence, toxicological mechanism, and management

The epidermal growth factor receptor (EGFR) family is a class of receptor tyrosine kinase playing a central role in carcinogenesis and cancer progression. The members of this family, particularly EGFR and human epidermal growth factor receptor 2 (HER2), are the most extensively studied drug targets for malignancy. Today, numerous tyrosine kinase inhibitors targeting EGFR family have been developed to combat non-small-cell lung cancer and breast cancer. However, severe gastrointestinal (GI) toxicity leading to dose reduction and treatment discontinuation hampers the therapeutic outcome of EGFR inhibitors. Diarrhea is one of the most frequent GI side effects, especially when it comes to second-generation EGFR inhibitors. Enterocytes apoptosis and increased inflammation accompany with many oral EGFR inhibitors. Loperamide and budesonide are the first-line treatment to manage such adverse effects. However, current prophylaxis and management are all empirical interventions to relieve the symptom. They do not specifically target the toxicological mechanism of EGFR inhibitors. Hereby, those anti-diarrhea agents do not work well when used in cancer patients experiencing EGFR inhibitor-induced diarrhea. On the other hand, the toxicological mechanism of EGFR inhibitor-induced diarrhea is poorly understood. Thus, determining the mechanism behind such diarrhea is urgently in need for developing genuinely effective anti-diarrhea agents. This review aims to call attention to EGFR inhibitor-induced diarrhea, a highly occurring and devastating cancer drug toxicity.

Targeting Neprilysin (NEP) pathways: A potential new hope to defeat COVID-19 ghost

COVID-19 is an ongoing viral pandemic disease that is caused by SARS-CoV2, inducing severe pneumonia in humans. However, several classes of repurposed drugs have been recommended, no specific vaccines or effective therapeutic interventions for COVID-19 are developed till now. Viral dependence on ACE-2, as entry receptors, drove the researchers into RAS impact on COVID-19 pathogenesis. Several evidences have pointed at Neprilysin (NEP) as one of pulmonary RAS components. Considering the protective effect of NEP against pulmonary inflammatory reactions and fibrosis, it is suggested to direct the future efforts towards its potential role in COVID-19 pathophysiology. Thus, the review aimed to shed light on the potential beneficial effects of NEP pathways as a novel target for COVID-19 therapy by summarizing its possible molecular mechanisms. Additional experimental and clinical studies explaining more the relationships between NEP and COVID-19 will greatly benefit in designing the future treatment approaches.

A randomized open label efficacy clinical trial of oral guava leaf decoction in patients with acute infectious diarrhoea

Background

Diarrhoea is amongst the first ten causes of death and its treatment faces an increased threat of drug resistance. Previous studies on the guava leaf decoction (GLD) revealed its suitability for use in infectious diarrhoea of unknown etiology.

Objective

The objective of this trial was to establish efficacy, dose and safety of GLD prepared from the Indian Sardar variety in adults with acute infectious diarrhoea.

Methods

The current trial was an open efficacy randomized 5-day, parallel group multi-arm interventional study. Amongst 137 adults (18–60 years) suffering with acute diarrhoea, 109 were included (57% females, 43% males). Three doses of GLD (6-leaf, 10-leaf and 14-leaf) were compared with controls receiving oral rehydration solution. Decrease in stool frequency and improvement in consistency were the outcomes measured. The data was analyzed using ANOVA, Tukey's post-hoc test, Kruscal-Wallis test and Chi-Square test where applicable.

Results

The trial showed that the 14-leaf (7.4 g) decoction was the most effective. Administration of the decoction, thrice daily helped the patients regain normalcy in 72 h as opposed to 120 h in controls. Safety of the intervention was reflected by normal levels of haemoglobin, liver and kidney parameters. No adverse events were reported.

Conclusion

The 14 leaves decoction was a safe treatment for adult acute uncomplicated diarrhoea of unknown etiology. Moreover due to component synergy and divergent mechanisms of action, it could possibly combat the generation of drug resistance and destruction of gut microbiota. Hence GLD has the potential for development as a first line treatment for diarrhoea.

Trial registration

Trial was registered with Clinical Trials Registry - India (CTRI registration number: CTRI/2016/07/007095). The trial was retrospectively registered.

Guideline for the Antibiotic Use in Acute Gastroenteritis

Acute gastroenteritis is common infectious disease in community in adults. This work represents an update of 'Clinical guideline for the diagnosis and treatment of gastrointestinal infections' that was developed domestically in 2010. The recommendation of this guideline was developed regarding the following; epidemiological factors, test for diagnosis, the indications of empirical antibiotics, and modification of antibiotics after confirming pathogen. Ultimately, it is expected to decrease antibiotic misuse and prevent antibiotic resistance.

Enkephalinase inhibitors, potential therapeutics for the future treatment of diarrhea predominant functional gastrointestinal disorders

The endogenous opioid system (EOS) is considered being a crucial element involved in the pathophysiology of irritable bowel syndrome (IBS) as it regulates gastrointestinal (GI) homeostasis through modulation of motility and water and ion secretion/absorption. Along with opioid receptors (ORs), the following components of EOS can be distinguished: 1. endogenous opioid peptides (EOPs), namely enkephalins, endorphins, endomorphins and dynorphins, and 2. peptidases, which regulate the metabolism (synthesis and degradation) of EOPs. Enkephalins, which are δ-opioid receptors agonists, induce significant effects in the GI tract as they act as potent pro-absorptive neurotransmitters. The action of enkephalins and other EOPs is limited, since EOPs are easily and rapidly inactivated by a natural metalloendopeptidase (enkephalinase/neprilysin) and aminopeptidase N. Studies show that the activity of EOPs can be enhanced by inhibition of these enzymes. In this review, we discuss the antidiarrheal and antinociceptive potential of enkephalinase inhibitors. Furthermore, our review is to answer the question whether enkephalinase inhibitors may be helpful in the future treatment of diarrhea predominant functional GI disorders.

Racecadotril in the treatment of acute diarrhea in children: a systematic, comprehensive review and meta-analysis of randomized controlled trials

BACKGROUND

Racecadotril is a guideline-recommended option for the treatment of acute diarrhea in children but existing guidelines and previous reviews of the field are based on a small fraction of published evidence. Therefore, we have performed a systematic search for randomized controlled trials evaluating racecadotril as add-on or in comparison to other treatments.

METHODS

A search was performed in PubMed, Scopus and Google Scholar without limits about country of origin or reporting language. A meta-analysis was conducted for the five most frequently used efficacy parameters.

RESULTS

We have retrieved 58 trials, from nine countries including six in comparison to placebo, 15 in comparison to various active treatments and 41 as add-on to various standard treatments (some multi-armed studies allowing more than one comparison). Trials used 45 distinct efficacy parameters, most often time to cure, % of cured children after 3 days of treatment, global efficacy and number of stools on second day of treatment. Racecadotril was superior to comparator treatments in outpatients and hospitalized patients with a high degree of consistency as confirmed by meta-analysis for the five most frequently used outcome parameters. For instance, it reduced time to cure from 106.2 h to 78.2 h (mean reduction 28.0 h; P < 0.0001 in 24 studies reporting on this parameter). Tolerability of racecadotril was comparable to that of placebo (10.4% vs. 10.6% adverse events incidence) or that of active comparator treatments other than loperamide (2.4% in both groups).

CONCLUSIONS

Based on a comprehensive review of the existing evidence, we conclude that racecadotril is more efficacious than other treatments except for loperamide and has a tolerability similar to placebo and better than loperamide. These findings support the use of racecadotril in the treatment of acute diarrhea in children.

Management of Acute Diarrheal Illness During Deployment: A Deployment Health Guideline and Expert Panel Report

BACKGROUND

Acute diarrheal illness during deployment causes significant morbidity and loss of duty days. Effective and timely treatment is needed to reduce individual, unit, and health system performance impacts.

METHODS

This critical appraisal of the literature, as part of the development of expert consensus guidelines, asked several key questions related to self-care and healthcare-seeking behavior, antibiotics for self-treatment of travelers' diarrhea, what antibiotics/regimens should be considered for treatment of acute watery diarrhea and febrile diarrhea and/or dysentery, and when and what laboratory diagnostics should be used to support management of deployment-related travelers' diarrhea. Studies of acute diarrhea management in military and other travelers were assessed for relevance and quality. On the basis of this critical appraisal, guideline recommendations were developed and graded by the Expert Panel using good standards in clinical guideline development methodology.

RESULTS

New definitions for defining the severity of diarrhea during deployment were established. A total of 13 graded recommendations on the topics of prophylaxis, therapy and diagnosis, and follow-up were developed. In addition, four non-graded consensus-based statements were adopted.

CONCLUSIONS

Successful management of acute diarrheal illness during deployment requires action at the provider, population, and commander levels. Strong evidence supports that single-dose antimicrobial therapy is effective in most cases of moderate to severe acute diarrheal illness during deployment. Further studies are needed to address gaps in available knowledge regarding optimal therapies for treatment, prevention, and laboratory testing of acute diarrheal illness.

[Consensus paper treatment of acute traveler's diarrhea. Practice recommendation for travel advice]

BACKGROUND

In times of mass tourism, traveler's diarrhea is one of the most common health problems of long-distance travel. Globally, some 40 million cases occur annually. Travellers to risk areas should therefore be comprehensively advised beforehand, as to what action to take in case of an acute traveler's diarrhea and what drugs to add to their first-aid kit. To date none, or hardly any specific studies or valid specific guidelines for the treatment of traveler's diarrhea are available for Germany.

METHOD

Drafting a consensus paper based on results of a specialists' meeting to evaluate therapeutic options in the treatment of acute uncomplicated travelers' diarrhea. The foundation for the present consensus recommendations is current evidence on antidiarrheals available in Germany for symptomatic treatment of gastrointestinal infections, summarized in the S2k guideline for gastrointestinal infections and Whipple's disease. Further taken into account for the present consensus recommendations were Pubmed-listed publications on symptomatic treatment of traveler's diarrhea, practical aspects, and the experts' experience in travel medicine.

RESULTS AND CONCLUSION

For the treatment of acute uncomplicated traveler's diarrhea - more than 90 % of all cases - the secretion inhibitor racecadotril is considered first choice, based on our evaluation criteria. The previously usual practice of recommending the antimotility drug loperamide as first choice should be reconsidered, in favor of the recent active ingredient racecadotril. Antibiotics should be used only in complicated cases. A large number of travelers who generally demand antibiotic therapy should be disabused of their expectations. Other therapeutic measures that are currently available for the treatment of acute diarrhea while traveling play a subordinate role.

Effects of Racecadotril on Weight Loss and Diarrhea Due to Human Rotavirus in Neonatal Gnotobiotic Pigs (Sus scrofa domesticus)

Diarrheal disease is the second leading cause of death in children younger than 5 y, and the most common cause of acute watery diarrhea in young children worldwide is rotaviral infection. Medicines to specifically reduce diarrhea would be a desirable adjunctive treatment to supportive fluid therapy to decrease the mortality rate of diarrheal diseases. In this study, we evaluated the efficacy of an antisecretory drug, racecadotril, in treating human rotavirus (HRV)-induced diarrhea in a neonatal gnotobiotic pig model. In total, 27 gnotobiotic pigs were randomly assigned (n = 9 per group) to receive either racecadotril, chlorpromazine (positive-control drug), or PBS (mock treatment) after inoculation with HRV. Pigs were weighed daily and rectal swabs were collected to determine fecal consistency scores and virus shedding. Rotaviral infection was confirmed by ELISA and cell culture immunofluorescence. Overall, the racecadotril-treated pigs had less severe illness than either the chlorpromazine- or mock-treated groups; this conclusion was supported by the lower fecal-consistency scores, shorter duration of diarrhea, and significant gain in body weight during the course of the study of the racecadotril-treated pigs. Through its influence on decreasing intestinal hypersecretion, racecadotril was better able to control the clinical signs of rotaviral infection in the gnotobiotic pigs. These results lend support for using racecadotril as a treatment for rotaviral diarrhea.

A Comprehensive Comparison of the Efficacy and Tolerability of Racecadotril with Other Treatments of Acute Diarrhea in Adults

Racecadotril is a guideline-recommended treatment to alleviate symptoms of acute diarrhea. A systematic review of randomized studies was performed comparing efficacy and safety of treatment with racecadotril to that with placebo or active treatments in adults. In five double-blind studies, racecadotril and placebo had comparable tolerability, but racecadotril was more effective. This was consistent across multiple efficacy parameters including duration of diarrhea, number of diarrheic stools, abdominal pain, and meteorism; it was also consistent across countries in Africa, Asia, and Europe. In six randomized studies in outpatients comparing racecadotril to loperamide, resolution of symptoms occurred with similar speed and efficacy; however, racecadotril treatment was associated with less rebound constipation and less abdominal discomfort. The seventh comparative study performed in geriatric nursing home residents reported a superior efficacy of racecadotril. In direct comparison with Saccharomyces boulardii treatment, racecadotril exhibited similar tolerability but was more efficacious. One study compared racecadotril to octreotide in patients with acute diarrhea requiring hospitalization, rehydration, and antibiotic treatment; in this cohort, octreotide was more efficacious than racecadotril. In conclusion, in adults with acute diarrhea, racecadotril is more efficacious than placebo or S. boulardii, similarly efficacious as loperamide and, in patients with moderate to severe disease as add-on to antibiotics, less than octreotide. The tolerability of racecadotril is similar to that of placebo or S. boulardii and better than that of loperamide, particularly with regard to risk of rebound constipation. Taken together, these data demonstrate that racecadotril is a suitable treatment to alleviate symptoms of acute diarrhea in adults.

Chemotherapy induced diarrhea

Purpose: To provide a current review of the literature related to chemotherapy induced diarrhea (CID), including clinical assessment, recommended management guidelines and investigational pharmacological approaches for the prevention and treatment of CID.

Data sources: A search of MEDLINE, PubMed, EMBASE, Cochrane Library, International Pharmaceutical Abstracts, and Web of Science (1996—2006) databases was conducted using terms such as: chemotherapy, diarrhea, diarrhoea, and irinotecan. Appropriate references from selected articles were also used. The search engine, Google, provided further access to information.

Data extraction: The retrieved literature was reviewed to include all articles pertaining to the pathophysiology, assessment and management of CID.

Data synthesis: Diarrhea is a debilitating and potentially life-threatening side effect associated with many chemotherapeutic agents. Despite the high incidence and severity of CID, it is often under recognized and poorly managed. A multidisciplinary panel recently updated recommended practice guidelines for the assessment and management of CID. Prompt and aggressive intervention is important in order to minimize the negative consequences of CID, such as dehydration, which may cause interruptions in optimal clinical outcomes or may lead to life-threatening sequelae. Further investigation into the pathophysiology of CID may allow for more directed approaches in the prophylaxis and treatment of CID. J Oncol Pharm Practice (2007) 13: 181—198.

ACG Clinical Guideline: Diagnosis, Treatment, and Prevention of Acute Diarrheal Infections in Adults

Acute diarrheal infections are a common health problem globally and among both individuals in the United States and traveling to developing world countries. Multiple modalities including antibiotic and non-antibiotic therapies have been used to address these common infections. Information on treatment, prevention, diagnostics, and the consequences of acute diarrhea infection has emerged and helps to inform clinical management. In this ACG Clinical Guideline, the authors present an evidence-based approach to diagnosis, prevention, and treatment of acute diarrhea infection in both US-based and travel settings.

Pharmacologic Comparison of Clinical Neutral Endopeptidase Inhibitors in a Rat Model of Acute Secretory Diarrhea

Racecadotril (acetorphan) is a neutral endopeptidase (NEP) inhibitor with known antidiarrheal activity in animals and humans; however, in humans, it suffers from shortcomings that might be improved with newer drugs in this class that have progressed to the clinic for nonenteric disease indications. To identify potentially superior NEP inhibitors with immediate clinical utility for diarrhea treatment, we compared their efficacy and pharmacologic properties in a rat intestinal hypersecretion model. Racecadotril and seven other clinical-stage inhibitors of NEP were obtained or synthesized. Enzyme potency and specificity were compared using purified peptidases. Compounds were orally administered to rats before administration of castor oil to induce diarrhea. Stool weight was recorded over 4 hours. To assess other pharmacologic properties, select compounds were orally administered to normal or castor oil–treated rats, blood and tissue samples collected at multiple time points, and active compound concentrations determined by mass spectroscopy. NEP enzyme activity was measured in tissue homogenates. Three previously untested clinical NEP inhibitors delayed diarrhea onset and reduced total stool output, with little or no effect on intestinal motility assessed by the charcoal meal test. Each was shown to be a potent, highly specific inhibitor of NEP. Each exhibited greater suppression of NEP activity in intestinal and nonintestinal tissues than did racecadotril and sustained this inhibition longer. These results suggest that newer clinical-stage NEP inhibitors originally developed for other indications may be directly repositioned for treatment of acute secretory diarrhea and offer advantages over racecadotril, such as less frequent dosing and potentially improved efficacy.

Traveler's Diarrhea

Travelers' diarrhea (TD) is the most important health issue among international travelers. In high risk areas, 50-90% of travelers may experience an episode of TD. The risk of acquiring TD is influenced by factors such as the destination, duration of stay, standard of accommodation, type of travel, age of the traveler, and also by individual risk factors. Most cases of TD are caused by bacteria; treatment for TD are loperamide and antibiotics. Preventive strategies such as hygiene measures have limited impact. Prophylactic intake of antibiotics or vaccines to prevent from TD can be considered in special situations.

Agents that act luminally to treat diarrhoea and constipation

Diarrhoea and constipation are common clinical complaints that negatively affect quality of life, reduce work productivity and lead to considerable health-care expenditure. A variety of therapies have been used to treat these conditions. Unlike drugs that require systemic absorption to exert their effects, luminally acting agents improve diarrhoea and constipation by altering intestinal and/or colonic motility, as well as mucosal absorption and secretion, through a variety of mechanisms. Examples of luminally acting agents for diarrhoea include peripherally acting opiate analogues, enkephalinase inhibitors, bile-acid binding agents, nonabsorbed antibiotics, probiotics, bismuth-containing compounds, berberine and agents with possible effects on intestinal secretion or permeability. Luminally acting drugs for constipation include bulking agents, surfactants, osmotics, stimulants, chloride-channel activators, probiotics, drugs that increase delivery of bile acids to the colon and natural therapies such as prunes and hemp seed extract. As the physiological effects of luminally acting drugs are largely confined to the gastrointestinal tract, these agents are unlikely to cause adverse effects outside of the gastrointestinal tract.

Treatment of chronic diarrhoea

The treatment of chronic diarrhoea can be challenging. While Oral Rehydration Solution is an important step in treating diarrhoeal illnesses, various medications can be used to alleviate the symptoms while the patient is undergoing diagnostic work up or to target the underlying mechanism responsible for their diarrhoea. Medications are also being prescribed in cases when there is a strong suspicious about a diagnosis or when there is no specific treatment for an underlying aetiology. This chapter discusses the treatment options for diarrhoeal disorders.

Recent advances in small bowel diseases: Part I

As is the case in all parts of gastroenterology and hepatology, there have been many advances in our knowledge and understanding of small intestinal diseases. Over 1000 publications were reviewed for 2008 and 2009, and the important advances in basic science as well as clinical applications were considered. In Part I of this Editorial Review, seven topics are considered: intestinal development; proliferation and repair; intestinal permeability; microbiotica, infectious diarrhea and probiotics; diarrhea; salt and water absorption; necrotizing enterocolitis; and immunology/allergy. These topics were chosen because of their importance to the practicing physician.

A comprehensive review of the pharmacodynamics, pharmacokinetics, and clinical effects of the neutral endopeptidase inhibitor racecadotril

Racecadotril, via its active metabolite thiorphan, is an inhibitor of the enzyme neutral endopeptidase (NEP, EC 3.4.24.11), thereby increasing exposure to NEP substrates including enkephalins and atrial natriuretic peptide (ANP). Upon oral administration racecadotril is rapidly and effectively converted into the active metabolite thiorphan, which does not cross the blood–brain-barrier. Racecadotril has mainly been tested in animal models and patients of three therapeutic areas. As an analgesic the effects of racecadotril across animal models were inconsistent. In cardiovascular diseases such as hypertension or congestive heart failure results from animal studies were promising, probably related to increased exposure to ANP, but clinical results have not shown substantial therapeutic benefit over existing treatment options in cardiovascular disease. In contrast, racecadotril was consistently effective in animal models and patients with various forms of acute diarrhea by inhibiting pathologic (but not basal) secretion from the gut without changing gastro-intestinal transit time or motility. This included studies in both adults and children. In direct comparative studies with loperamide in adults and children, racecadotril was at least as effective but exhibited fewer adverse events in most studies, particularly less rebound constipation. Several guidelines recommend the use of racecadotril as addition to oral rehydration treatment in children with acute diarrhea.

Infective and inflammatory diarrhoea: mechanisms and opportunities for novel therapies

There have been significant advances in unravelling the cellular mechanisms of diarrhoea in common gut infections and colonic inflammation, as well as in the identification of targets for potential antidiarrhoeal drugs. Infective diarrhoea reflects activation of electrogenic Cl⁻ secretion, inhibition of electroneutral NaCl absorption and in some cases, downregulation of tight junctional proteins and increased apoptosis. In colonic inflammation, diarrhoea mainly reflects impairment of colonic Na⁺ and Cl⁻ absorption by inflammatory cytokines, leading to decreased water absorption. Stimulation of endogenous opiate-dependent pathways, manipulation of epithelial ion (Na⁺, K⁺ and Cl⁻) channels and suppression of proinflammatory cytokine production by a variety of drugs and novel molecules, offer opportunities to move evaluation of these potential antisecretory and anti-inflammatory agents from the laboratory into clinical trials.

Pre-hospital management of diarrhoea among caregivers presenting at a tertiary health institution: implications for practice and health education

BACKGROUND

Diarrhoeal diseases cause significant childhood morbidity and mortality worldwide. The effectiveness of home management of diarrhoeal diseases is achievable only if caregivers have appropriate information despite varying recommendations on the strategies for diarrhoea therapy.

OBJECTIVES

To evaluate caregivers' perception and use of ORT fluids for management of diarrhoea in under-five age children in the face of varying phases of recommendations, as an indicator of home treatment.

METHODS

Caregivers of U5 children presenting with acute watery diarrhoea to different Paediatrics clinics/wards of the University of Nigeria Teaching Hospital (U.N.T.H.), Enugu between October 2006 and February 2007 were interviewed with a structured questionnaire.

RESULT

Caregivers of 156 under-five children who met the inclusion criteria were recruited. Access to ORT fluids was high with 73.1% of all children with diarrhoea being offered an ORT fluid at home. However, the method of preparation and administration of fluids was quite unsatisfactory. Previous experience with ORT fluids, higher educational or socioeconomic status did not correlate significantly with better performance.

CONCLUSION

Despite high level of knowledge and acceptance of ORT among the study population actual practice was not satisfactory. Diverse practices by caregivers which represent the various phases of evolution in the types of fluids promoted for oral rehydration reflect some confusion that require urgent attention. Knowledge and skills of ORT need to be widely promoted on a continuing basis with the need for health workers to ensure that caregivers are taught and adhere to the correct recommendations on oral rehydration therapy.

Diarrhoea in adults (acute)

INTRODUCTION

An estimated 4.6 billion cases of diarrhoea occurred worldwide in 2004, resulting in 2.2 million deaths.

METHODS AND OUTCOMES

We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of treatments for acute diarrhoea in adults living in resource-rich countries? What are the effects of treatments for acute mild-to-moderate diarrhoea in adults from resource-rich countries travelling to resource-poor countries? What are the effects of treatments for acute mild-to-moderate diarrhoea in adults living in resource-poor countries? What are the effects of treatments for acute severe diarrhoea in adults living in resource-poor countries? We searched: Medline, Embase, The Cochrane Library, and other important databases up to January 2010 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).

RESULTS

We found 72 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.

CONCLUSIONS

In this systematic review we present information relating to the effectiveness and safety of the following interventions: antibiotics, antimotility agents, antisecretory agents, bismuth subsalicylate, diet, intravenous rehydration, nasogastric tube rehydration, oral rehydration solutions (amino acid oral rehydration solution, bicarbonate oral rehydration solution, reduced osmolarity oral rehydration solution, rice-based oral rehydration solution, standard oral rehydration solution), vitamin A supplementation, and zinc supplementation.

Pharmacological management of diarrhea

According to the World Health Organization, there are approximately 2 billion annual cases of diarrhea worldwide. Diarrhea is the leading cause of death in children younger than 5 years and kills 1.5 million children each year. It is especially prevalent in the developing world, where mortality is related to dehydration, electrolyte disturbance, and the resultant acidosis, and in 2001, it accounted for 1.78 million deaths (3.7% of total deaths) in low- and middle-income countries. However, diarrhea is also a common problem in the developed world, with 211 million to 375 million episodes of infectious diarrheal illnesses in the United States annually, resulting in 73 million physician consultations, 1.8 million hospitalizations, and 3100 deaths. Furthermore, 4% to 5% of the Western population suffers from chronic diarrhea. Given the high prevalence of diarrhea, research has been directed at learning more about the cellular mechanisms underlying diarrheal illnesses in order to develop new medications directed at novel cellular targets. These cellular mechanisms and targets are discussed in this article.

Systematic review: the epidemiology and clinical features of travellers' diarrhoea

BACKGROUND

Travellers' diarrhoea is the most common medical complaint among persons venturing into developing areas from industrialized regions.

AIM

To review recent developments dealing with microbiological, clinical, pathophysiological and therapeutic aspects of travellers' diarrhoea.

METHODS

The author's extensive file plus a review of publications listed in PubMed on January 22, 2009 on the topic of travellers' diarrhoea were reviewed.

RESULTS

Travellers' diarrhoea is largely caused by detectable and undetected bacterial enteropathogens, explaining the remarkable effectiveness of antibacterial agents in prophylaxis and therapy of the illness. A number of host genetic polymorphisms have been recently linked with susceptibility to travellers' diarrhoea. Novel antisecretory agents are being developed for treatment considering their physiological effects in acute diarrhoea. All travellers should be armed with one of three antibacterial drugs, ciprofloxacin, rifaximin or azithromycin, before their trips to use in self therapy should diarrhoea occur during travel. Loperamide may treat milder forms of travellers' diarrhoea and can be employed with antibacterial drugs.

CONCLUSIONS

Diarrhoea will continue to plague international travellers to high-risk regions. More studies of the incidence rate, relative important of the various pathogens by geographical region of the world, host risk factors and optimal therapeutic approach are needed.

Focus on acute diarrhoeal disease

Diarrhoea is an alteration of normal bowel movement characterized by an increase in the water content, volume, or frequency of stools. Diarrhoea needs to be classified according to the trends over time (acute or chronic) and to the characteristics of the stools (watery, fatty, inflammatory). Secretory diarrhoeas, mostly acute and of viral aetiology in more than 70% of cases, are by far the most important subtype of diarrhoeas in terms of frequency, incidence and mortality (over 2.5 million deaths/year in developing countries). Natural and synthetic opiates such as morphine, codeine, and loperamide which react with endogenous opiates (enkephalins, beta-endorphins, dynorphins) mainly act on intestinal motility and slow down transit. An antidiarrhoeal drug developed in recent years, racecadotril, acts as an enkephalinase inhibitor. Clinical studies have shown that it is just as effective as loperamide in resolving acute diarrhoea but with greater reduction in pain and abdominal distension. Some studies have explored the prevalence of diarrhoea in old age. An epidemiological study carried out in Italy by 133 General Practitioners on 5515 elderly outpatients reported a prevalence of diarrhoea, defined according to the Rome criteria, of 9.1%. Infectious diseases (19%) and drug use (16%) were the most common causes of diarrhoea in old age. Regardless of the cause, the treatment of elderly patients with diarrhoea must include rehydration and nutritional support. Every year, more than 50 million tourists travel from industrialized countries to places where hygiene levels are poor. At least 75% of those travelling for short periods mention health problems, and in particular traveller’s diarrhoea.

Use of racecadotril as outpatient treatment for acute gastroenteritis: a prospective, randomized, parallel study

OBJECTIVE

To compare the efficacy of therapy with racecadotril plus oral rehydration versus oral rehydration alone in children with gastroenteritis in an outpatient setting care.

STUDY DESIGN

Prospective, randomized, open and parallel study performed in a Pediatric Emergency Service of a tertiary care hospital. The study included 189 patients, ages 3 to 36 months, with acute gastroenteritis: 94 were administered an oral rehydration solution (OR), 94 received oral rehydration solution plus racecadotril (OR + R). The principal variable studied was the number of bowel movements in 48 hours after initiating treatment.

RESULTS

The groups were comparable clinically and epidemiologically at enrollment. No significant differences were found in the number of bowel movements between the 2 groups 48 hours after initiating treatment (4.1 +/- 2.7 bowel movements in the OR group vs 3.8 +/- 2.4 bowel movements in the OR + R group). No differences were found in the average duration of gastroenteritis (4.7 +/- 2.2 days in the OR group, 4.0 +/- 2.1 days in the OR + R group; P = .15). The incidence of adverse events was similar in both groups (19 patients [20.2%] in the OR group, 18 patients [19.1%] in the OR + R group).

CONCLUSIONS

In our study group, the use of racecadotril did not improve the symptoms of diarrhea compared with standard rehydration therapy.

Antimotility agents for chronic diarrhoea in people with HIV/AIDS

BACKGROUND

AIDS-related diarrhoea is a common cause of morbidity and mortality in HIV positive individuals, especially in the sub-Saharan Africa where 70% of deaths from HIV occur. It often compromises quality of life both in those receiving antiretroviral therapy (ART) and the ART naive. Empirical antidiarrhoeal treatment may be required in about 50% of cases which are non-pathogenic or idiopathic and in cases resulting from antiretroviral therapy. Antimotility agents (Loperamide, Diphenoxylate, Codeine) and adsorbents (Bismuth Subsalicylate, Kaolin/Pectin, Attapulgite) are readily available, and have been found to be useful in this condition and so, are often used. Antimotilitics are opioids, decreasing stool output by reducing bowel activity thereby increasing fecal transit time in the gut, promoting fluid and electrolyte retention while adsorbents act by binding to fluids, toxins and other substances to improve stool consistency and eliminate the toxins. Due to its potential impact on the management of chronic diarrhoea in persons with HIV/AIDS, we reviewed the effectiveness of antimotility agents in controlling chronic diarrhoea in immunocompromised states caused by HIV/AIDS.

OBJECTIVES

To assess the effectiveness of antimotility agents in controlling chronic diarrhoea in people with HIV/AIDS.

SEARCH STRATEGY

We searched Medline, EMBASE, the Cochrane Controlled Trials Register, the Cochrane HIV/AIDS Register and AIDSearch databases in November 2006. We also contacted WHO, CDC, pharmaceutical companies and experts in the field for information on previous or on-going trials and checked reference list from retrieved studies, irrespective of language and publication status.

SELECTION CRITERIA

Randomised controlled trials comparing an antimotility agent or an adsorbent with another antimotility agent, placebo, an adsorbent or no treatment in children and adults diagnosed with HIV and presenting with diarrhoea of three or more weeks duration.

DATA COLLECTION AND ANALYSIS

Two authors independently undertook study selection and examined full articles of potentially eligible studies.

MAIN RESULTS

One trial was found assessing the use of an adsorbent (attapulgite) compared to a placebo for chronic diarrhoea in people with HIV/AIDS. It included 91 adults (Aged 18 to 60), diagnosed with AIDS and experiencing diarrhoea for at least 7 days. There was no evidence that attapulgite is superior to placebo in controlling diarrhoea by reducing stool frequency and normalising stool consistency on days 1 (0.34 (95% CI 0.01 - 8.15)), 3 (1.35 (95% CI 0.51 - 3.62)) and 5 (1.74 (95% CI 0.89 - 3.38)). This was a small trial and may not have had enough power to show evidence of effects. Five deaths were reported which was not classified according to the arms of the study.Studies assessing the use of antimotility agents were not found.

AUTHORS' CONCLUSIONS

This review highlights the absence of evidence for the use of antimotility agents and adsorbents in controlling diarrhoea in people with HIV/AIDS. While no trials assessing the use of Antimotilitics were found, the retrieved study showed that attapulgite was not better than placebo in controlling diarrhoea in HIV/AIDS patients . For optimum patient care, these agents can still be used, with greater emphasis placed on adjunct therapies like massive fluid replacement while evidence for practice is awaited from further studies and reviews.

Diarrhoea in adults (acute)

INTRODUCTION

An estimated 4000 million cases of diarrhoea occurred worldwide in 1996, resulting in 2.5 million deaths.

METHODS AND OUTCOMES

We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of treatments for acute diarrhoea in adults living in resource-rich countries? What are the effects of treatments for acute mild-to-moderate diarrhoea in adults from resource-rich countries traveling to resource-poor countries? What are the effects of treatments for acute mild-to-moderate diarrhoea in adults living in resource-poor countries? What are the effects of treatments for acute severe diarrhoea in adults living in resource-poor countries? We searched: Medline, Embase, The Cochrane Library and other important databases up to January 2007 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).

RESULTS

We found 71 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.

CONCLUSIONS

In this systematic review we present information relating to the effectiveness and safety of the following interventions: antibiotics, antimotility agents, antisecretory agents, bismuth subsalicylate, diet, intravenous rehydration, nasogastric tube rehydration, and oral rehydration solutions (amino acid oral rehydration solution, bicarbonate oral rehydration solution, reduced osmolarity oral rehydration solution, rice-based oral rehydration solution, standard oral rehydration solution).

Use of preproenkephalin knockout mice and selective inhibitors of enkephalinases to investigate the role of enkephalins in various behaviours

RATIONALE

The most simple and efficient method to study the physiological role of enkephalins is to increase the lifetime of these endogenous opioid peptides by inhibiting their inactivating enzymes. Enkephalins are degraded by the concomitant action of two metallopeptidases: neutral endopeptidase (NEP, EC3.4.21.11) and aminopeptidase N (APN, EC3.4.11.2), both enzymes releasing inactive metabolites.

OBJECTIVES

Potent dual inhibitors have been developed, such as RB101. However, NEP and APN have a broad specificity and can cleave various peptides in vitro. Therefore, it was essential to investigate the specific involvement of enkephalins in the various pharmacological responses induced by dual inhibitors.

MATERIALS AND METHODS

We compared the pharmacological responses induced by RB101 in wild-type and preproenkephalin-deficient mice (Penk1-/-) using several behavioural assays.

RESULTS

In all the tests used (hot plate test, force swim test, castor-oil-induced diarrhoea), RB101 induced strong effects in wild-type animals, whereas slight effects were observed in Penk1-/- animals. These residual effects are blocked by pre-administration of the opioid antagonist naloxone, supporting the involvement of the opioid receptors in the responses observed.

CONCLUSIONS

The pharmacological effects induced by dual inhibitors acting on both NEP and APN are mainly due to the protection of the endogenous enkephalins at supraspinal and peripheral levels. It could be speculated that the residual effects observed in Penk1-/- mice after RB101 administration could be due to the direct action of other opioid peptides or through an indirect effect involving the protection of other peptide substrates of NEP or APN, as substance P or angiotensin.

Advances in defining etiology and new therapeutic approaches in acute diarrhea

Defining etiology of acute diarrhea is critical to disease therapy and prevention. In this review we look at recent developments in etiologic agents of acute diarrhea and advances in therapy and prevention of the illness. Newly appreciated agents include enterotoxigenic Bacteroides fragilis, Klebsiella oxytoca and Laribacter hongkongensis. Atypical enteropathogenic E. coli (EPEC) strains lacking the gene for epithelial attachment appear to be more important as causes of diarrhea than traditional EPEC strains. Enterotoxigenic E. coli and enteroaggregative E. coli diarrhea known to be important abroad, have recently been shown to occur in the United States. Non-O157:H7 strains of Shiga toxin-producing E. coli are increasing and infrequently are being sought. There is currently a serious epidemic of nosocomial diarrhea due to a fluoroquinolone-resistant and more virulent and difficult to treat strain of C. difficile. Rotavirus vaccine development should lead to reduction of infant gastroenteritis mortality in infants living in developing regions. Noroviruses produce outbreaks of water- and food-borne disease but show broad genetic diversity. Reduced osmolarity oral rehydration treatment (ORT) and recombinant human lactoferrin/lysozyme plus rice-based ORT effectively treat acute diarrhea. Probiotics were shown to be effective in preventing antibiotic associated- and C. difficile-diarrhea. Rifaximin prevents and azithromycin effectively treats travelers' diarrhea.

Diarrhoea in the critically ill

PURPOSE OF REVIEW

The purpose of this review is to update the knowledge on diarrhoea, a common problem in critically ill patients. Epidemiological data will be discussed, with special emphasis on diarrhoea in tube-fed patients and during antibiotic therapy. The possible preventive and therapeutic measures will be presented.

RECENT FINDINGS

The need for concise definitions of diarrhoea was recently re-emphasized. The use of pump-driven continuous instead of intermittent enteral feeding is less often associated with diarrhoea. The discontinuation of enteral feeding during diarrhoea is not justified. Clostridium difficile-associated diarrhoea is frequent during antibiotic therapy with quinolones and cephalosporins. Formulas enriched with water-soluble fibres are probably effective to prevent diarrhoea, and promising data on the modulation of gut microflora with probiotics and prebiotics were recently released.

SUMMARY

Diarrhoea is common in critically ill patients, especially when sepsis and hypoalbuminaemia are present, and during enteral feeding and antibiotic therapy. The management of diarrhoea includes generous hydration, compensation for the loss of electrolytes, antidiarrheal oral medications, the continuation of enteral feeding, and metronidazole or glycopeptides in the case of moderate to severe C. difficile colitis. The place of enteral formulas enriched with water-soluble fibres, probiotics and prebiotics is not yet fully defined.

Current status of anti-diarrheal and anti-secretory drugs in the management of acute childhood diarrhea

Each year 1.8 million children die due to diarrheal diseases. Indiscriminate use of antibiotics has resulted in increasing resistance to commonly used antibiotics. Moreover the recent outbreaks of shigella and cholera have revealed multi-drug resistance strains. There is a need for review of recommended antibiotics for shigellosis. From recent data it emerges that fluoroquinolones should be the first line of therapy and cephalosporins to be used as the second line. Among the anti-cholera antibiotics, tetracyclines which were the drug of choice for adults, has the advantage of high sensitivity and low cost. Single dose doxycycline would have minimal side effects, hence can be the drug of choice even in children. We should not allow the business pressures to force usage of probiotics and racecadotril as their role in the management of acute diarrhea is yet to be established. Nitazoxanide has high efficacy against Cryptosporodial diarrhea only. Strict adherence to the recommendations for the management of acute childhood diarrhea is needed or else we dilute the effect of standard management.