Effects of lactulose and polyethylene glycol on colonic transit

Lactulose vs Polyethylene Glycol for Bowel Preparation: A Single-Center, Prospective, Randomized Controlled Study Based on BMI

INTRODUCTION

Colonoscopy is currently considered as one of the principal techniques to diagnose the colorectal diseases. Admittedly, qualified bowel preparation before colonoscopy is a premise for high-quality examination. Lower quality bowel preparation might seriously impede visualization of the intestinal mucosa, resulting in missed and misdiagnosed intestinal lesions. Therefore, it is necessary to choose the appropriate oral laxative based on the guarantee of safety and efficacy.

METHODS

This prospective randomized controlled study was conducted to compare lactulose oral solution and polyethylene glycol (PEG) electrolyte powder for bowel preparation using the following indicators: Boston Bowel Preparation Scale, Bowel Bubble Score, detection rate of adenoma and lesion, patients' satisfaction, and adverse effects. Our study investigated the suitability of 2 bowel preparation reagents for patients with different body mass indices mainly based on body mass index (BMI).

RESULTS

In the lactulose group, there was a significant improvement in the quality of bowel preparation compared with those in the PEG group ( P < 0.05), especially in people with normal BMI and higher BMI. Compared with the PEG group, individuals in the lactulose group had a significantly higher adenoma detection rate (50% vs 33.5%, P < 0.05) and taste scores (8.82 vs 6.69, P < 0.05), as well as significantly fewer adverse reactions (6.5% vs 32.5%, P < 0.05).

DISCUSSION

Lactulose oral solution is superior to PEG in bowel preparation quality and taste, especially in normal BMI and higher BMI groups. It can be used clinically as a potential and promising bowel preparation agent in the future. Clinical Trial registration number: ChiCTR2100054318.

Roles of Gut Microbiota and Metabolites in Pathogenesis of Functional Constipation

Functional constipation (FC), a condition characterized by heterogeneous symptoms (infrequent bowel movements, hard stools, excessive straining, or a sense of incomplete evacuation), is prevalent over the world. It is a multifactorial disorder and can be categorized into four subgroups according to different pathological mechanisms: normal transit constipation (NTC), slow transit constipation (STC), defecatory disorders (DD), and mixed type. Recently, growing evidence from human and animals has pointed that there was a strong association between gut microbiota and FC based on the brain-gut-microbiome axis. Studies have reported that the main characteristics of gut microbiota in FC patients were the relative decrease of beneficial bacteria such as Lactobacillus and Bifidobacterium, the relative increase of potential pathogens, and the reduced species richness. Gut microbiota can modulate gut functions through the metabolites of bacterial fermentation, among which short-chain fatty acids (SCFAs), secondary bile salts (BAs), and methane occupied more important positions and could trigger the release of gut hormones from enteroendocrine cells (EECs), such as 5-hydroxytryptamine (5-HT), peptide YY (PYY), and glucagon-like peptide-1 (GLP-1). Subsequently, these gut hormones can influence gut sensation, secretion, and motility, primarily through activating specific receptors distributed on smooth muscle cells, enteric neurons, and epithelial cells. However, research findings were inconsistent and even conflicting, which may be partially due to various confounding factors. Future studies should take the associated confounders into consideration and adopt multiomics research strategies to obtain more complete conclusions and to provide reliable theoretical support for exploring new therapeutic targets.

European guideline on indications, performance, and clinical impact of hydrogen and methane breath tests in adult and pediatric patients: European Association for Gastroenterology, Endoscopy and Nutrition, European Society of Neurogastroenterology and Motility, and European Society for Paediatric Gastroenterology Hepatology and Nutrition consensus

Introduction

Measurement of breath hydrogen (H₂) and methane (CH₄) excretion after ingestion of test‐carbohydrates is used for different diagnostic purposes. There is a lack of standardization among centers performing these tests and this, together with recent technical developments and evidence from clinical studies, highlight the need for a European guideline.

Methods

This consensus‐based clinical practice guideline defines the clinical indications, performance, and interpretation of H₂‐CH₄‐breath tests in adult and pediatric patients. A balance between scientific evidence and clinical experience was achieved by a Delphi consensus that involved 44 experts from 18 European countries. Eighty eight statements and recommendations were drafted based on a review of the literature. Consensus (≥80% agreement) was reached for 82. Quality of evidence was evaluated using validated criteria.

Results

The guideline incorporates new insights into the role of symptom assessment to diagnose carbohydrate (e.g., lactose) intolerances and recommends that breath tests for carbohydrate malabsorption require additional validated concurrent symptom evaluation to establish carbohydrate intolerance. Regarding the use of breath tests for the evaluation of oro‐cecal transit time and suspected small bowel bacterial overgrowth, this guideline highlights confounding factors associated with the interpretation of H₂‐CH₄‐breath tests in these indications and recommends approaches to mitigate these issues.

Conclusion

This clinical practice guideline should facilitate pan‐European harmonization of diagnostic approaches to symptoms and disorders, which are very common in specialist and primary care gastroenterology practice, both in adult and pediatric patients. In addition, it identifies areas of future research needs to clarify diagnostic and therapeutic approaches.

Effect of intestinal dialysis using polyethylene glycol on fluid balance and thirst in maintenance hemodialysis patients: A comparative study

High inter-dialytic weight gains (IDWG) and Hyperkalemia have been associated with adverse outcomes like poor quality of life and high mortality. Thirst remains an unsolved problem in hemodialysis (HD) patients. The aim of this study was to evaluate the effect of polyethylene glycol (PEG) based intestinal dialysis on IDWG, thirst and biochemical parameters. A prospective interventional evidenced based paired comparative single center study was conducted. Thirty-five anuric patients on weekly thrice HD were studied for four consecutive dialysis weeks. Before the mid-week dialysis day of week 3, Patients received 2 L PEG solution. The primary end points were change in mean relative IDWG and change in mean subjective thirst feeling as measured on visual analog scale (VAS) with secondary endpoints being change in small molecule clearance. There was significant reduction in IDWG after the therapy from 3 ± 0.81 L to 2.35 ± 0.72 (P = 0.002). The therapy also reduced the % IDWG BW from 5.1 ± 1.7% to 4.15 ± 1.6% (P = 0.017). No change in thirst was seen, that is, 6.16 ± 0.66, 6.14 ± 0.64, and 6.16 ± 0.65 (P = 0.986). A multivariate linear regression did not reveal any effect of age, gender, and co-morbidities on the reduction of IDWG and thirst. The therapy achieved a significant urea, creatinine, and potassium reduction of 8.23%, 8.13%, and 8.33% respectively with an increase in sodium levels by 0.86%. This modality reduced the IDWG, was found to be a potent treatment modality for hyperkalemia but did not affect thirst sensation even after consumption of 2 L solution.

Blood glucose response after oral lactulose intake in type 2 diabetic individuals

BACKGROUND

Lactulose is approved for the symptomatic treatment of constipation, a gastrointestinal (GI) complication common in individuals with diabetes. Lactulose products contain carbohydrate impurities (e.g., lactose, fructose, galactose), which occur during the lactulose manufacturing process. These impurities may affect the blood glucose levels of individuals with type 2 diabetes mellitus (T2DM) using lactulose for the treatment of mild constipation. A previous study in healthy subjects revealed no increase in blood glucose levels after oral lactulose intake. However, it is still unclear whether the intake of lactulose increases blood glucose levels in individuals with diabetes.

AIM

To evaluate the blood glucose profile after oral lactulose intake in mildly constipated, non-insulin-dependent subjects with T2DM in an outpatient setting.

METHODS

This prospective, double-blind, randomized, controlled, single-center trial was conducted at the Clinical Research Center at the Medical University of Graz, Austria, in 24 adult Caucasian mildly constipated, non-insulin-dependent subjects with T2DM. Eligible subjects were randomized and assigned to one of six treatment sequences, each consisting of four treatments stratified by sex using an incomplete block design. Subjects received a single dose of 20 g or 30 g lactulose (crystal and liquid formulation), water as negative control or 30 g glucose as positive control. Capillary blood glucose concentrations were measured over a period of 180 min post dose. The primary endpoint was the baseline-corrected area under the curve of blood glucose concentrations over the complete assessment period [AUC_{baseline_c (0-180 min)}]. Quantitative comparisons were performed for both lactulose doses and formulations vs water for the equal lactulose dose vs glucose, as well as for liquid lactulose vs crystal lactulose. Safety parameters included GI tolerability, which was assessed at 180 min and 24 h post dose, and adverse events occurring up to 24 h post dose.

RESULTS

In 24 randomized and analyzed subjects blood glucose concentration-time curves after intake of 20 g and 30 g lactulose were almost identical to those after water intake for both lactulose formulations despite the different amounts of carbohydrate impurities (≤ 3.0% for crystals and approx. 30% for liquid). The primary endpoint [AUC_{baseline_c (0-180 min)}] was not significantly different between lactulose and water regardless of lactulose dose and formulation. Also with regard to all secondary endpoints lactulose formulations showed comparable results to water with one exception concerning maximum glucose level. A minor increase in maximum blood glucose was observed after the 30 g dose, liquid lactulose, in comparison to water with a mean treatment difference of 0.63 mmol/L (95% confidence intervals: 0.19, 1.07). Intake of 30 g glucose significantly increased all blood glucose endpoints vs 30 g liquid and crystal lactulose, respectively (all P < 0.0001). No differences in blood glucose response were observed between the different lactulose formulations. As expected, lactulose increased the number of bowel movements and was generally well tolerated. Subjects experienced only mild to moderate GI symptoms due to the laxative action of lactulose.

CONCLUSION

Blood glucose AUC_{baseline_c (0-180 min)} levels in mildly constipated, non-insulin dependent subjects with T2DM are not affected by the carbohydrate impurities contained in 20 g and 30 g crystal or liquid lactulose formulations.

Chronic Constipation: Gastroenterohepatologist's Approach

BACKGROUND

Constipation is a common problem in gastroenterological practice. The prevalence of constipation is about 16%. Constipation can be primary or secondary.

SUMMARY

The diagnostic and therapeutic approach to patients with constipation begins with a detailed history and physical examination. In selected cases, the use of additional diagnostic procedures is very important. This includes the use of laboratory, endoscopic, and radiological examinations, as well as advanced physiological testing (anorectal manometry, balloon expulsion test, colonic transit studies, and defecography). Constipation therapy can be both nonoperative and operative. Nonoperative therapy includes the application of a lifestyle measures, pharmacotherapy and biofeedback therapy. Key Messages: Two key things when taking a medical history and physical examination are to rule out the existence of alarm symptoms/signs and to rule out secondary constipation (primarily drug-induced). Therapy begins with lifestyle modification, and in case of failure, bulk or osmotic laxatives are used. In case of failure, the use of lubiprostone is indicated, as well as linaclotide. Surgical treatment of constipation is reserved for cases of refractory constipation, with delayed intestinal transit.

Fecal Clostridiales distribution and short-chain fatty acids reflect bowel habits in irritable bowel syndrome

Irritable bowel syndrome (IBS), a common functional gastrointestinal disorder, is classified according to bowel habits as IBS with constipation (IBS-C), with diarrhea (IBS-D), with alternating constipation and diarrhea (IBS-M), and unsubtyped (IBS-U). The mechanisms leading to the different IBS forms are mostly unknown. This study aims to evaluate whether specific fecal bacterial taxa and/or short-chain fatty acids (SCFAs) can be used to distinguish IBS subtypes and are relevant for explaining the clinical differences between IBS subcategories. We characterized five fecal samples collected at 4-weeks intervals from 40 IBS patients by 16S rRNA gene profiling and SCFA quantification. Finally, we investigated the potential correlations in IBS subtypes between the fecal microbial signatures and host physiological and clinical parameters. We found significant differences in the distribution of Clostridiales OTUs among IBS subtypes and reduced levels of SCFAs in IBS-C compared to IBS-U and IBS-D patients. Correlation analyses showed that the diverse representation of Clostridiales OTUs between IBS subtypes was associated with altered levels of SCFAs; furthermore, the same OTUs and SCFAs were associated with the fecal cytokine levels and stool consistency. Our results suggest that intestinal Clostridiales and SCFAs might serve as potential mechanistic biomarkers of IBS subtypes and represent therapeutic targets.

Longer colonic transit time is associated with laxative and drug use, lifestyle factors, and symptoms of constipation

BACKGROUND

Gastrointestinal symptoms and changes in colonic transit time (CTT) are common in the population.

PURPOSE

To evaluate consecutive patients who had been examined for CTT, along with completion of a diary about laxative and drug use, lifestyle factors, and gastrointestinal symptoms, to identify possible associations with longer or prolonged CTT.

MATERIAL AND METHODS

A total of 610 consecutive patients had undergone the radiopaque marker method with an abdominal X-ray for clinical purposes. The patients had completed a diary regarding medical treatment, lifestyle factors, stool habits, and their perceived constipation and abdominal pain during the examination period. The associations between CTT and laxative use, lifestyle factors, stool habits, and symptoms were calculated by logistic regression.

RESULTS

Women had longer CTT (2.5 [1.6-3.9] vs. 1.7 [1.1-3.0] days, P < 0.001), lower weekly stool frequency (6 [3-10] vs. 8 [5-12], P = 0.001), and perceived more constipation (P = 0.025) and abdominal pain (P = 0.001) than men. High coffee consumption (P = 0.045), bulk-forming (P = 0.007) and osmotic (P = 0.001) laxatives, and lower stool frequency, shaped stool, and perceived constipation (P for trend < 0.001) were associated with longer CTT. In total, 382 patients (63%) were treated with drugs affecting motility. In the 228 patients without drug treatment, longer CTT was associated with female sex and smoking, and lower frequency of symptoms and prolonged CTT were observed compared to patients using drugs. Tea, alcohol, and abdominal pain did not associate with CTT.

CONCLUSIONS

Female sex, coffee, smoking, drug use, infrequent stools, shaped stool, and perception of constipation are associated with longer or prolonged CTT.

Effects of medicines used to treat gastrointestinal diseases on the pharmacokinetics of coadministered drugs: a PEARRL Review

Objectives

Drugs used to treat gastrointestinal diseases (GI drugs) are widely used either as prescription or over-the-counter (OTC) medications and belong to both the 10 most prescribed and 10 most sold OTC medications worldwide. The objective of this review article is to discuss the most frequent interactions between GI and other drugs, including identification of the mechanisms behind these interactions, where possible.

Key findings

Current clinical practice shows that in many cases, these drugs are administered concomitantly with other drug products. Due to their metabolic properties and mechanisms of action, the drugs used to treat gastrointestinal diseases can change the pharmacokinetics of some coadministered drugs. In certain cases, these interactions can lead to failure of treatment or to the occurrence of serious adverse events. The mechanism of interaction depends highly on drug properties and differs among therapeutic categories. Understanding these interactions is essential to providing recommendations for optimal drug therapy.

Summary

Interactions with GI drugs are numerous and can be highly significant clinically in some cases. While alterations in bioavailability due to changes in solubility, dissolution rate, GI transit and metabolic interactions can be (for the most part) easily identified, interactions that are mediated through other mechanisms, such as permeability or microbiota, are less well-understood. Future work should focus on characterising these aspects.

Macrogol (polyethylene glycol) 4000 without electrolytes in the symptomatic treatment of chronic constipation: a profile of its use

Macrogol 4000, a biologically inert, non-absorbable osmotic laxative, is a highly effective and well-tolerated first-line option for the treatment of the symptoms of chronic idiopathic/functional constipation in children and adults. High-molecular-weight (HMW) macrogols ± electrolytes have generally similar efficacy profiles; however, the taste of macrogol 4000 is generally preferred over that of macrogol 3350 + electrolytes. Macrogol 4000 is more effective than lactulose in improving stool frequency and consistency, and is associated with less vomiting and flatulence. Comparisons with other osmotic and bulk-forming laxatives are limited, with macrogol 4000 being at least as, or more effective than, psyllium hydrocolloid and magnesium hydroxide in treating chronic constipation. Current clinical treatment guidelines recommend the use of HMW macrogols over the use of lactulose and bulk-forming laxative in the symptomatic treatment of constipation in children and adults.

Analysis of short-chain fatty acids in human feces: A scoping review

Short-chain fatty acids (SCFAs) play a crucial role in maintaining homeostasis in humans, therefore the importance of a good and reliable SCFAs analytical detection has raised a lot in the past few years. The aim of this scoping review is to show the trends in the development of different methods of SCFAs analysis in feces, based on the literature published in the last eleven years in all major indexing databases. The search criteria included analytical quantification techniques of SCFAs in different human clinical and in vivo studies. SCFAs analysis is still predominantly performed using gas chromatography (GC), followed by high performance liquid chromatography (HPLC), nuclear magnetic resonance (NMR) and capillary electrophoresis (CE). Performances, drawbacks and advantages of these methods are discussed, especially in the light of choosing a proper pretreatment, as feces is a complex biological material. Further optimization to develop a simple, cost effective and robust method for routine use is needed.

Cirrhotic Patients Have Worse Bowel Preparation at Screening Colonoscopy than Chronic Liver Disease Patients without Cirrhosis

BACKGROUND

Cirrhosis has been shown in small studies to be a predictor of suboptimal bowel preparation at screening colonoscopy. It has yet to be established whether patients with chronic liver disease in the absence of cirrhosis experience equally poor colon cleansing. Intestinal dysmotility related to cirrhosis might impair bowel preparation in this population more than those with chronic liver disease without cirrhosis.

OBJECTIVE

This study compared the quality of bowel preparation in cirrhotic and non-cirrhotic patients with chronic liver disease and determined whether this influenced polyp detection rate.

METHODS

A retrospective study of patients with chronic liver disease, both cirrhotic and non-cirrhotic, who underwent screening colonoscopy was performed. Patient characteristics, concomitant medication use, adequacy of bowel preparation, and the total number and types of polyps found were compared between cirrhotic and non-cirrhotic groups.

RESULTS

330 patients fulfilled inclusion criteria; 36% (n = 120) were cirrhotic. Cirrhotic patients had significantly worse bowel preparation scores compared with non-cirrhotics (mean 3.4 ± 1.1 vs. 3.7 ± 0.9, P = 0.003). Worse bowel preparation scores in cirrhotics vs. non-cirrhotics persisted despite controlling for age, sex, and concomitant diabetes mellitus (DM) (P = 0.0027). Among the cirrhotics, 48% had the lowest preparation scores compared with 30% of non-cirrhotics. No difference in polyp detection rate was found between cirrhotics and non-cirrhotics. Severity of cirrhosis as assessed by the MELD score did not predict worse bowel preparation.

CONCLUSIONS

Cirrhotics have significantly worse bowel preparation scores compared to non-cirrhotics with chronic liver disease. No correlation between MELD score and bowel preparation score was observed in the cirrhotic cohort.

Intestinal microbiota and diet in IBS: causes, consequences, or epiphenomena?

Irritable bowel syndrome (IBS) is a heterogeneous functional disorder with a multifactorial etiology that involves the interplay of both host and environmental factors. Among environmental factors relevant for IBS etiology, the diet stands out given that the majority of IBS patients report their symptoms to be triggered by meals or specific foods. The diet provides substrates for microbial fermentation, and, as the composition of the intestinal microbiota is disturbed in IBS patients, the link between diet, microbiota composition, and microbial fermentation products might have an essential role in IBS etiology. In this review, we summarize current evidence regarding the impact of diet and the intestinal microbiota on IBS symptoms, as well as the reported interactions between diet and the microbiota composition. On the basis of the existing data, we suggest pathways (mechanisms) by which diet components, via the microbial fermentation, could trigger IBS symptoms. Finally, this review provides recommendations for future studies that would enable elucidation of the role of diet and microbiota and how these factors may be (inter)related in the pathophysiology of IBS.

Effect and safety of deep needling and shallow needling for functional constipation: a multicenter, randomized controlled trial

Aupuncture is widely used for functional constipation. Effect of acupuncture might be related to the depth of needling; however, the evidence is limited. This trial aimed to evaluate the effect and safety of deep needling and shallow needling for functional constipation, and to assess if the deep needling and shallow needling are superior to lactulose. We conducted a prospective, superiority-design, 5-center, 3-arm randomized controlled trial. A total of 475 patients with functional constipation were randomized to the deep needling group (237), shallow needling group (119), and lactulose-controlled group (119) in a ratio of 2:1:1. Sessions lasted 30 minutes each time and took place 5 times a week for 4 weeks in 2 acupuncture groups. Participants in the lactulose group took lactulose orally for 16 continuous weeks. The primary outcome was the change from baseline of mean weekly spontaneous bowel movements (SBMs) during week 1 to 4 (changes from the baselines of the weekly SBMs at week 8 and week 16 in follow-up period were also assessed simultaneously). Secondary outcomes were the weekly SBMs of each assessing week, the mean score change from the baseline of constipation-related symptoms over week 1 to 4, and the time to the first SBM. Emergency drug usage and adverse effects were monitored throughout the study.SBMs and constipation-related symptoms were all improved in the 3 groups compared with baseline at each time frame (P<0.01, all). The changes in the mean weekly SBMs over week 1 to 4 were 2 (1.75) in the deep needling group, 2 (1.75) in the shallow needling group, and 2 (2) in the lactulose group (P>0.05, both compared with the lactulose group). The changes of mean weekly SBMs at week 8 and week 16 in the follow-up period were 2 (2), 2 (2.5) in the deep needling group, 2 (3), 1.5 (2.5) in the shallow needling group, and 1 (2), 1 (2) in the lactulose group (P<0.05, all compared with the lactulose group). No significant difference was observed among the 3 groups regarding the score changes of straining, incomplete evacuation, abdominal distention during spontaneous defecating, or Cleveland Clinic Scores over week 1 to 4. However, the lactulose group got better effect than other 2 acupuncture groups in improving stool consistency (P<0.01, both) and shortening the time to the first SBM (P<0.05, both). The percentage of emergency drugs used in the 2 acupuncture groups were both lower than in the lactulose group at each time frame (P<0.01, all). No obvious adverse event was observed in the deep or shallow needling group. Deep and shallow needling at Tianshu (ST25) can improve intestinal function remarkably and safely. Therapeutic effects of deep and shallow needling are not superior to that of lactulose; however, the sustained effects of deep and shallow needling after stopping the acupuncture treatments are superior to the therapeutic effect of lactulose, which might qualify the superiority of deep and shallow needling.

Glucose absorption in small intestinal diseases

Recent developments in the field of diabetes and obesity management have established the central role of the gut in glucose homeostasis; not only is the gut the primary absorptive site, but it also triggers neurohumoral feedback responses that regulate the pre- and post-absorptive phases of glucose metabolism. Structural and/or functional disorders of the intestine have the capacity to enhance (e.g.: diabetes) or inhibit (e.g.: short-gut syndrome, critical illness) glucose absorption, with potentially detrimental outcomes. In this review, we first describe the normal physiology of glucose absorption and outline the methods by which it can be quantified. Then we focus on the structural and functional changes in the small intestine associated with obesity, critical illness, short gut syndrome and other malabsorptive states, and particularly Type 2 diabetes, which can impact upon carbohydrate absorption and overall glucose homeostasis.

Randomised clinical trial: macrogol/PEG 3350+electrolytes versus prucalopride in the treatment of chronic constipation -- a comparison in a controlled environment

BACKGROUND

Constipation is a common condition for which PEG 3350 is an established treatment and prucalopride has recently been approved for this indication.

AIM

To compare the efficacy, safety and impact on quality of life (QoL) of PEG 3350 plus electrolytes (PEG 3350+E) vs. prucalopride in females with chronic constipation (CC) in whom laxatives have previously failed to provide adequate relief.

METHODS

In this single-centre, randomised, double-blind, double-dummy study, patients with CC [<3 spontaneous complete bowel movements (SCBM)/week] remained in a controlled environment and received either a 26 g split dose of PEG 3350+E (N = 120) or 1-2 mg prucalopride (N = 120) daily for 28 days following a 14-day run-in period. The primary endpoint was the proportion of patients having ≥3 SCBMs during the last treatment week.

RESULTS

Non-inferiority of PEG 3350+E to prucalopride was demonstrated in the per-protocol population [difference, 10.1% (66.67% vs. 56.52%), 97.5% lower confidence interval (CI) -2.7%, above the preset margin of -20%] and approached superiority in the modified intent-to-treat population (difference, 9.8%, 97.5% lower CI, -3.1%). Statistically significant differences in favour of PEG 3350+E were observed for most secondary variables (bowel movements, stool weight, consistency, time to next SCBM, patient perception of straining and completeness of defecation). Colonic transit time was dramatically reduced in both arms. Both treatments were well tolerated.

CONCLUSION

PEG 3350+E was at least as effective as and generally better tolerated than prucalopride as a treatment for chronic constipation in this study population (NCT01251822; http://www.clinicaltrials.gov).

Diarrhea caused by carbohydrate malabsorption

This article will focus on the role of the colon in the pathogenesis of diarrhea in carbohydrate malabsorption or physiologically incomplete absorption of carbohydrates, and on the most common manifestation of carbohydrate malabsorption, lactose malabsorption. In addition, incomplete fructose absorption, the role of carbohydrate malabsorption in other malabsorptive diseases, and congenital defects that lead to malabsorption will be covered. The article concludes with a section on diagnostic tools to evaluate carbohydrate malabsorption.

6β-N-heterocyclic substituted naltrexamine derivative NAP as a potential lead to develop peripheral mu opioid receptor selective antagonists

A 6β-N-heterocyclic substituted naltrexamine derivative, NAP, was proposed as a peripheral mu opioid receptor (MOR) selective antagonist based on the in vitro and in vivo pharmacological and pharmacokinetic studies. To further validate this notion, several functional assays were carried out to fully characterize this compound. In the charcoal gavage and intestinal motility assay in morphine-pelleted mice, when administered 0.3 mg/kg or higher doses up to 3 mg/kg subcutaneously, NAP significantly increased the intestinal motility compared to the saline treatment. The comparative opioid withdrawal precipitation study and the lower locomotor assay demonstrated that NAP showed only marginal intrinsic effect in the central nervous system either given subcutaneously or intravenously: no jumps were witnessed for the tested animals even given up to a dose of 50 mg/kg, while similar noticeable wet-dog shakes only occurred at the dose 50 times of those for naloxone or naltrexone, and significant reduction of the hyper-locomotion only happened at the dose as high as 32 mg/kg. Collectively, these results suggested that NAP may serve as a novel lead to develop peripheral MOR selective antagonist which might possess therapeutic potential for opioid-induced bowel dysfunction (OBD), such as opioid-induced constipation (OIC).

A literature review of two laxatives: lactulose and polyethylene glycol

This paper presents a literature review of two commonly used osmotic laxatives, lactulose and polyethylene glycol (PEG). With increasing numbers of nurses in the community being non-medical prescribers, informed decisions on choice of laxatives is required. Nurses who do not prescribe will often have a view for the benefit of their patients. Following a literature search, eight papers were selected for review. The review leads to the conclusion that, while both preparations are useful, PEG is more effective in many instances and should be the laxative of choice unless there are contraindications arising from the assessment of the patient. Non-pharmacological approaches to the management of constipation should be addressed before considering laxative use.

Rifaximin treatment for reduction of risk of overt hepatic encephalopathy recurrence

Hepatic encephalopathy (HE) is a common problem in patients with chronic liver disease and is characterized by diminished mentation and neuromuscular abnormalities. Symptoms range from subtle cognitive changes to coma and death. Gut-derived toxins such as ammonia are thought to play a central role in the pathogenesis of HE. Treatment strategies are directed at increased elimination or reduction of gut-derived ammonia in addition to correction of dynamic conditions that provoke bouts of HE. The standard of care for treatment of acute HE is lactulose, a nonabsorbable disaccharide that is thought to increase elimination and reduce absorption of ammonia. Although lactulose seems to work in the acute setting, the rate of recurrent HE on maintenance lactulose is high. Medications have been sought that reduce the rate of recurrent HE in patients at high risk for HE but none have been identified. Rifaximin is a poorly absorbed antibiotic that is thought to reduce ammonia production by eliminating ammonia-producing colonic bacteria. Many small studies have suggested that rifaximin is effective in treating acute HE and is extremely well tolerated. This led to a randomized, placebo-controlled, multicenter, multinational trial investigating the efficacy of rifaximin over a 6-month period in reducing the risk of recurrent HE in patients at baseline, but with a history of at least two bouts of acute HE in the previous 6 months prior to enrollment. Lactulose could be administered at the discretion of the investigator. A total of 299 patients were randomized to receive rifaximin or placebo; 91% of patients in each group received lactulose. Compared with placebo, patients at high risk for recurrent HE in the rifaximin group had highly statistically significant reductions in bouts of acute HE (58%) and reductions in hospitalizations related to HE (50%) over a 6-month period. The medication was well tolerated with a side-effect profile comparable to placebo. This led to the approval of rifaximin for reduction of risk of recurrent HE by the US Food and Drug Administration in March 2010. It is recommended that patients with a history of recurrent acute HE should be maintained on rifaximin with or without lactulose to reduce the risk of recurrent HE and related hospitalization.

A randomized, double-blind, placebo-controlled trial of polyethylene glycol effects on fasting and postprandial rectal sensitivity and symptoms in hypersensitive constipation-predominant irritable bowel syndrome

AIM

To assess the effect of polyethylene glycol 3350 (PEG) on fasting and postprandial (PP) perception of rectal distension and symptoms in hypersensitive constipation-predominant irritable bowel syndrome (IBS-C).

METHODS

Forty-two patients meeting Rome II criteria for IBS-C and with a pain threshold of < 32 mmHg were included in a randomized, double-blind, placebo-controlled trial. Patients received either oral PEG, 3.45 g t.i.d. orally for 30 days or placebo. Rectal sensitivity was assessed before and after treatment with a barostat using the ascending method of limits, during basal and PP periods.

RESULTS

No changes in fasting and PP rectal tone and thresholds for first sensation, gas sensation, urge to defecate, and pain was observed with PEG in relation to placebo. In both groups, pressure at which patients crossed the thresholds for noxious (PEG: from 28 ± 8.8 to 22 ± 6.9 mmHg) and non noxious (PEG: from 16 ± 4.9 to 12 ± 3.6 mmHg) stimuli decreased compared with pretreatment values. PEG improved consistency of faeces and showed a trend to diminish blood in faeces. PEG and placebo increased bowel movements per week (P < 0.001), and relieved symptoms without significant side-effects.

CONCLUSIONS

Both PEG 3350 and placebo were clinically useful in patients with IBS-C, an effect that cannot be explained by changes in rectal tone and sensation. The results support the concept that visceral sensitivity is not stable and has a heterogeneous response to drugs, and suggest the existence of a post healing hypersensitivity state.

Lactulose versus Polyethylene Glycol for Chronic Constipation

BACKGROUND

Constipation is a common clinical problem. Lactulose and Polyethylene Glycol (PEG) are both commonly used osmotic laxatives that have been shown to be effective and safe treatments for chronic constipation. However, there is no definitive data as to which provides the best treatment.

OBJECTIVES

To identify and review all relevant data in order to determine whether Lactulose or Polyethylene Glycol is more effective at treating chronic constipation and faecal impaction.

SEARCH STRATEGY

We searched the MEDLINE, EMBASE and CINAHL databases, and the Cochrane Central Register of Controlled Trials for all randomised controlled trials (RCTs) comparing the use of lactulose and polyethylene glycol in the management of faecal impaction and chronic constipation.

SELECTION CRITERIA

Studies were included if they were randomised controlled trials which compared lactulose with polyethylene glycol in the management of chronic constipation.

DATA COLLECTION AND ANALYSIS

Data on study methods, participants, interventions used and outcomes measured was extracted from each study. Data was entered into the Cochrane Review Manager software (RevMan 5.0) and analysed using Cochrane MetaView.

MAIN RESULTS

In the present meta-analysis, we considered for the first time all ten randomised controlled trials so far performed. The findings of our work indicate that Polyethylene glycol is better than lactulose in outcomes of stool frequency per week, form of stool, relief of abdominal pain and the need for additional products. On subgroup analysis, this is seen in both adults and children, except for relief of abdominal pain.

AUTHORS' CONCLUSIONS

Polyethylene Glycol should be used in preference to Lactulose in the treatment of Chronic Constipation.

Efficacy and tolerability of Laxatan Granulat in patients with chronic constipation

Background:

On average 12% of the population worldwide suffer from acute or chronic constipation. Pathological intestine alterations, an unhealthy diet with reduced liquid intake, and little exercise are potential reasons. Often the motility of the intestine is disturbed. Changing nutrition habits or lifestyle is not always successful. In such cases, laxatives containing macrogol and inulin are highly effective.

Methodology:

The efficacy and tolerability of Laxatan^® Granulat, a laxative containing macrogol, inulin, and mineral salts, was assessed in a drug-monitoring study of 105 patients for four weeks.

Results:

At the end of this study, a highly significant reduction of the constipation symptoms in 98.1% of the patients was observed. No adverse events were reported during this drug-monitoring study. The overall efficacy was rated as being “very good” or “good” for 96% and the overall tolerability was rated as being “very good” or “good” for 99% of patients.

Conclusion:

The combination of macrogol, inulin, and mineral salts is highly effective in the treatment of chronic constipation. Due to its prebiotic activity, inulin probably leads to proliferation of lactic acid-producing bacteria. The lowered pH and increased water content probably increases the peristaltic action and therefore reduces constipation.

Hepatic encephalopathy

Hepatic encephalopathy (HE) is a syndrome of neuropsychiatric dysfunction caused by portosystemic venous shunting, with or without intrinsic liver disease. Patients with hepatic encephalopathy often present with the onset of mental status changes ranging from subtle psychologic abnormalities to profound coma. Several hypotheses have been proposed to explain the mental impairment associated with portosystemic shunting and liver disease. Clinicians diagnosing HE frequently have the opportunity to intervene and reverse severe HE, even hepatic coma. The recent advances in understanding and management of HE are the subject of this article.

Effects of therapeutic doses of lactulose vs. polyethylene glycol on isotopic colonic transit

BACKGROUND

Lactulose and polyethylene glycol are osmotic agents used to treat idiopathic chronic constipation.

AIM

To compare the effects of low doses of lactulose and PEG 4000 on transit time measured by scintigraphy in normal subjects.

METHODS

For 5 days, 10 healthy subjects received either 10 g b.d. of lactulose or PEG 4000 in a randomized, double-blind, crossover study. On the evening of day 4, they took a capsule containing Amberlite resin pellets labelled with (111)In. On day 5, after a 1000 kcal test meal labelled with 99 Tcm, gastric, small bowel and colonic transits were measured.

RESULTS

Gastric emptying and small bowel transit time were not different. Ascending colon emptying curve was significantly accelerated with lactulose in comparison with polyethylene glycol (P = 0.001) and, respectively, 50 +/- 18% vs. 35 +/- 18% of the radioactivity had left the ascending colon at the end of the study (P < 0.05). The descending colon filling curves, variations in the geometric centre and numbers of scintigraphic movements were not different.

CONCLUSIONS

In healthy subjects, in comparison to PEG 4000, usual therapeutic doses of lactulose significantly accelerate ascending colon emptying. This result supports a stimulating motor effect of colonic fermentation of lactulose.

Lower gastrointestinal functions

The human colon serves to absorb water and electrolytes, store intraluminal contents until elimination is socially convenient, and salvage nutrients by bacterial metabolism of carbohydrates that have not been absorbed in the small intestine. The anorectum is responsible for fecal continence and defecation. This article is a broad perspective of the current status and a personal perspective of future challenges in understanding lower gastrointestinal functions in health and disease in humans.

Lactulose breath testing does not discriminate patients with irritable bowel syndrome from healthy controls

INTRODUCTION

Recent reports suggest that abnormalities of lactulose breath testing (LBT) are common in patients with irritable bowel syndrome (IBS), although the criteria for abnormal studies are poorly validated, and controlled comparisons are limited. The goal of this study was to determine the prevalence of abnormal LBT using the previously published criteria in both IBS patients and healthy controls, as well as to determine the prevalence and symptom association with methane (CH(4)) and hydrogen (H(2)) productions during LBT.

METHODS

Consecutive LBT from patients meeting Rome II criteria for IBS and healthy control subjects were examined. Patients listed their most bothersome digestive symptom at the start of the test. LBT was performed using 10 g of lactulose mixed in 240 mL of water, and breath samples collected every 20 min for a 180-min period. Both breath H(2) and CH(4) were measured. LBT was considered positive if it met any of the previously published criteria: (a) breath H(2) of > 20 parts per million (ppm), (b) increase in breath H(2) in < 90 min, (c) dual H(2) peaks (12-ppm increase over baseline with a decrease of > or = 5 ppm before 2nd peak), and (d) breath CH(4) of > 1 ppm.

RESULTS

In total, 224 patients with IBS and 40 controls were studied. Twenty percent of IBS patients were CH(4)(+) compared with 15% of controls. CH(4)(+) IBS patients were significantly more likely than CH(4)(-) IBS patients to have constipation, and significantly less likely to have diarrhea; however, the association did not hold for symptoms of bloating or pain. Patients and controls did not differ significantly with respect to the frequency of a positive study defined by increase in breath H(2) in < 90 min (121 per 180 vs 26 per 40, P = 0.79), increase in breath H(2) of > 20 ppm (92 per 180 vs 24 per 40, P= 0.31), or dual peaks (25 per 180 vs 9 per 40, P = 0.17).

CONCLUSIONS

The majority of patients with IBS and healthy subjects meet criteria for an "abnormal" LBT using previously published test criteria, and groups are not discriminated using this diagnostic method. Similarly, while CH(4) production was associated with constipation among IBS patients, the prevalence of CH(4)-positive subjects did not significantly differ between IBS patients and controls. The utility of LBT, in its current form as a diagnostic tool in IBS requires critical reappraisal.

Multicenter, 4-week, double-blind, randomized, placebo-controlled trial of lubiprostone, a locally-acting type-2 chloride channel activator, in patients with chronic constipation

OBJECTIVES

To assess the efficacy and safety of lubiprostone in adults with chronic constipation.

METHODS

This multicenter, parallel-group, double-blind controlled trial enrolled 242 patients with constipation and randomized them to receive oral lubiprostone 24 mcg or placebo twice daily for 4 wk. The primary efficacy end point was the number of spontaneous bowel movements (SBMs; those occurring without use of constipation relieving medications) after 1 wk of double-blind treatment. Other evaluations included SBMs at weeks 2, 3, and 4; bowel movement (BM) characteristics (i.e., consistency and straining); constipation severity; abdominal bloating/discomfort; global treatment effectiveness ratings; and safety assessments.

RESULTS

The 120 lubiprostone-treated patients reported a greater mean number of SBMs at week 1 compared with the 122 placebo-treated patients (5.69 vs 3.46, P= 0.0001), with a greater frequency of SBMs also reported at weeks 2, 3, and 4 (P<or= 0.002). Within 24 h of the first dose of study drug, 56.7% of those given lubiprostone reported a SBM compared with 36.9% of those given placebo (P= 0.0024); within 48 h, 80% and 60.7% of these patients reported a SBM (P= 0.0013), respectively. Stool consistency, straining, and constipation severity, as well as patient-reported assessments of treatment effectiveness, were significantly improved with lubiprostone compared with placebo at all weeks (P<or= 0.0003). The two most common treatment-related adverse events were nausea (31.7%) and headache (11.7%).

CONCLUSIONS

In patients with chronic constipation, treatment with lubiprostone produces a BM in the majority of individuals within 24-48 h of initial dosing and improves the frequency as well as other characteristics associated with BMs with short-term (i.e., 4 wk) treatment. The most commonly reported adverse event was mild to moderate nausea, which resulted in treatment discontinuation in 5% of treated patients.

Treating chronic constipation : How should we interpret the recommendations?

Chronic constipation is a multisymptom gastrointestinal motility disorder that negatively impacts the lives of those affected. New recommendations on diagnosing and treating this condition have recently been published. This review aims to assist clinicians in applying these recommendations in clinical practice. Although lifestyle interventions and bulking agents help some patients with constipation, data are lacking to support their efficacy in those with chronic constipation. If empirical treatment of patients with chronic constipation fails, osmotic laxatives (e.g. lactulose and polyethylene glycol), a serotonin (5-HT4) receptor agonist (e.g. tegaserod) or a chloride channel activator (e.g. lubiprostone) can be considered. Osmotic laxatives, though effective at increasing stool frequency, are often associated with adverse effects such as bloating and diarrhoea and typically do not effectively relieve the multiple symptoms of chronic constipation. Use of tegaserod and the recently approved lubiprostone is supported by high-quality evidence, and these agents have acceptable safety profiles in patients with chronic constipation. Recent advances in the definition of chronic constipation and in its pharmacological management have led to refinements in identifying the appropriate treatment needs of patients with this condition. It is hoped that these advancements will help clinicians select effective medical regimens for patients with chronic constipation.

Gastrointestinal symptoms in patients with liver cirrhosis: associations with nutritional status and health-related quality of life

OBJECTIVE

Gastrointestinal symptoms can lead to decreased food intake and thereby increased morbidity. There is a general lack of data on the prevalence of gastrointestinal symptoms and their potential association with malnutrition and health-related quality of life (QoL) in cirrhosis. Our aim was to prospectively evaluate gastrointestinal symptoms, malnutrition, and QoL in patients with cirrhosis.

MATERIAL AND METHODS

Two validated questionnaires were used to measure gastrointestinal symptoms (gastrointestinal symptom rating scale (GSRS)) and health-related QoL (SF-36) in 128 consecutive cirrhotics (mean age 57 years, Child-Pugh score 8.6, MELD score 13.2) at a tertiary referral center. The results were compared with those of controls from the general population. Nutritional status was assessed by anthropometry and estimation of recent weight change.

RESULTS

Compared to controls, cirrhotic patients showed higher gastrointestinal symptom severity (total GSRS score: 1.53, 95% CI 1.50-1.55 versus 2.21, 95% CI 2.04-2.38) and profound reductions in the SF-36 physical (47.0 95% CI 45.0-49.0 versus 37.9, 95% CI 35.7-40.1) and mental component summary scores (51.0 95% CI 49.0-53.0 versus 39.2 95% CI 36.7-41.6). There were no significant differences in any GSRS domain between patients with and those without malnutrition. Multivariate analysis showed that gastrointestinal symptom severity was associated with the Child-Pugh score (beta = 0.10, r<0.05), daily lactulose use (beta = 0.65, p<0.005), and the presence of gastrointestinal comorbidities (beta = 0.51, p<0.05). Negative weight change (beta = -0.72, p<0.05) and the SF-36 physical (beta = -4.26, p<0.005) and mental (beta = -4.53, p<0.005) summaries were independently related to gastrointestinal symptom severity.

CONCLUSIONS

Patients with cirrhosis show increased severity of gastrointestinal symptoms, which are associated with recent weight loss and impaired health-related QoL. The severity of gastrointestinal symptoms seems to be related to the severity of cirrhosis.

Defecation disorders: neuromuscular aspects and treatment

Chronic constipation and fecal incontinence affect 20% of the population and are more prevalent in women, the elderly, those of lower socioeconomic status, and nursing home residents. These disorders pose a significant economic burden and affect quality of life. During the past decade, significant strides have been made in the understanding and treatment of defecation disorders, which have led to real advances in the management of these disorders. These treatments include biofeedback therapy, tegaserod, and lubiprostone for chronic constipation.

Evaluation of polyethylene glycol plus electrolytes in the treatment of severe constipation and faecal impaction in adults

INTRODUCTION

Extreme and severe cases of constipation can lead to faecal impaction. Current therapies are often both ineffective and unpleasant. The objective of this trial was to evaluate the efficacy and safety of Movicol, a polyethylene glycol (PEG) + electrolyte solution (PEG+E), as treatment for severe constipation and faecal impaction.

PATIENTS

56 patients (aged 17 to 88 years) with a history of chronic constipation and presenting with no bowel movement for three to four days (severe constipation), or no bowel movement for at least five days (faecal impaction), were enrolled at three centres in Taiwan. Faecal loading was confirmed in all patients by abdominal and rectal examination or abdominal radiography. Patients were excluded from the study if they had a gastrointestinal obstruction, evidence of delayed gastric emptying, or if their constipation was secondary to severe inflammatory bowel disease.

TREATMENT

All patients followed the same regimen: up to eight 13.8 g sachets of PEG+E (two at a time in 250 ml water; maximum of 1L/day) over a 4-6 h period each day, with 1-1.5 h between each dosing. Duration of treatment was for up to three days. EFFICACY ENDPOINTS AND RESULTS: Patients with either improvement (passage of a moderate to large volume of stool within four days of treatment initiation) or complete resolution (passage of moderate to large volumes of faecal matter plus the disappearance of palpable faecal masses in the abdomen and/or rectum) were considered responders. Based on bowel movement data recorded by the patients, an excellent response rate was obtained: 50/56 patients had a successful response to treatment (89.3%; 95% confidence intervals [CIs] 77.4% to 95.6%); there were 39 complete responders and 11 patients showed improvement. Investigator assessment of response was almost the same: 87.5% (95% CIs 75.3% to 94.4%). All bowel movement measurements (stool volume, number of evacuations, stool form and ease of evacuations) showed a positive improvement by Day 2. Median duration of treatment was two days. The incidence of adverse events was low, even for those side-effects such as abdominal pain and bloating, which are known undesirable consequences of PEG+E administration. No patient discontinued from the study because of an adverse event.

CONCLUSION

PEG+E, administered orally at a dose equivalent to eight 13.8 g sachets (1 L) per day over three days, was a highly effective and well tolerated therapy for the treatment of severe constipation and faecal impaction.