Mechanisms of drug-induced diarrhoea in the elderly

Multidose misoprostol pharmacokinetics and its effect on the fecal microbiome in healthy, adult horses

OBJECTIVE

To compare the pharmacokinetics between repeated doses and to characterize changes in the fecal microbiome after oral and rectal multidose misoprostol administration.

ANIMALS

6 healthy university-owned geldings.

PROCEDURES

In a randomized, crossover study, misoprostol (5 μg/kg) was administered orally or rectally every 8 hours for 10 doses, or not administered (control), with a 21-day washout between treatments. Concentration-versus-time data for dose 1 and dose 10 were subject to noncompartmental analysis. For microbiota analysis using 16S rRNA amplicon sequencing, manure was collected 7 days before study onset, immediately before dose 1, and 6 hours, 7 days, and 14 days after dose 10, with time-matched points in controls.

RESULTS

Repeated dosing-related differences in pharmacokinetic parameters were not detected for either administration route. The area under the concentration-versus-time curve was greater (P < .04) after oral versus rectal administration. The relative bioavailability of rectal administration was 4 to 86% of that of oral administration. Microbial composition, richness, and β-diversity differed among subjects (P < .001 all) while only composition differed between treatments (P ≤ .01). Richness was decreased 6 hours after dose 10 and at the control-matched time point (P = .0109) in all subjects. No other differences for time points, treatments, or their interactions were observed.

CLINICAL RELEVANCE

Differences in systemic exposure were associated with the route of administration but were not detected after repeated administration of misoprostol. Differences in microbiota parameters were primarily associated with interindividual variation and management rather than misoprostol administration.

A Review Of Preclinical Tools To Validate Anti-Diarrheal Agents

BACKGROUND

Since their inception, preclinical experimental models have played an important role in investigating and characterizing disease pathogenesis. These in vivo, ex vivo, and in vitro preclinical tests also aid in identifying targets, evaluating potential therapeutic drugs, and validating treatment protocols.

INTRODUCTION

Diarrhea is a leading cause of mortality and morbidity, particularly among children in developing countries, and it represents a huge health-care challenge on a global scale. Due to its chronic manifestations, alternative anti-diarrheal medications must be tested and developed because of the undesirable side effects of currently existing anti-diarrheal drugs.

METHODS

Several online databases, including Science Direct, PubMed, Web of Science, Google Scholar and Scopus, were used in the literature search. The datasets were searched for entries of studies up to May, 2022.

RESULTS

The exhaustive literature study provides a large number of in vivo, in vitro and ex vivo models, which have been used for evaluating the mechanism of the anti-diarrheal effect of drugs in chemically-, pathogen-, disease-induced animal models of diarrhea. The advances and challenges of each model were also addressed in this review.

CONCLUSION

This review encompasses diverse strategies for screening drugs with anti-diarrheal effects and covers a wide range of pathophysiological and molecular mechanisms linked to diarrhea, with a particular emphasis on the challenges of evaluating and predictively validating these experimental models in preclinical studies. This could also help researchers find a new medicine to treat diabetes more effectively and with fewer adverse effects.

Common Diarrheal Illnesses in the Elderly

Diarrhea is a fairly common problem among the elderly that has a higher morbidity and mortality compared with the general population. There are multiple reasons for diarrhea in the elderly that can be stratified by different mechanisms: infectious, osmotic, secretory, inflammatory, and malabsorptive. Oral hydration and dietary management are the basic management principles for all forms of diarrhea but specific treatment should address the root cause of diarrhea in order to improve outcomes.

Dispelling Myths and Unfounded Practices About Enteral Nutrition

Many protocols and steps in the process of enteral nutrition (EN) use are not overly supported with strong research and have been done the same way over many years without questioning the use of best-practices evidence. This article reports many of the myths and unfounded practices surrounding EN and attempts to refute those myths with current evidence. These practices include those about enteral access devices, formulas, enteral administration, and complications.

Drug-Induced Small Bowel Injury: a Challenging and Often Forgotten Clinical Condition

PURPOSE OF REVIEW

Most drugs are given by the oral route. Oral intake allows direct contact between the drug and the entire GI tract mucosa, exposing it to potential topical damage until absorption. Medication-induced GI symptoms and lesions are therefore commonly encountered in clinical practice. This review will examine the most common drugs or classes of drugs affecting small bowel function and/or structure.

RECENT FINDINGS

Since non-steroidal anti-inflammatory drugs (NSAIDs) are among the most widely used medicines, NSAID enteropathy is highly prevalent and brings about considerable morbidity. Antimicrobials and proton-pump inhibitors profoundly modify intestinal microbiota, affecting gut sensory and motor functions, while other drugs (like iron and gold derivatives) impair intestinal permeability. Olmesartan (and likely ACE inhibitors) induce villous atrophy and consequent malabsorption. Mycophenolate mofetil, cancer chemotherapeutic agents, and immune checkpoint inhibitors cause intestinal inflammation, abdominal pain, and diarrhea. Potassium chloride supplements may induce small bowel ulceration, stenosis, and perforation while the cotraceptive pill and anticoagulants are associated with intestinal ischemia and spontaneous intramural hematoma, respectively. In clinical practice, a deep knowledge of clinical pharmacology and toxicology and a high degree of suspicion of drug-related adverse events are mandatory. Only then, the practicing physician will be able to diagnose medication-induced small bowel lesions correctly and will implement the best strategies to treat them.

Identification of Novel, Structurally Diverse, Small Molecule Modulators of GPR119

GPR119 drug discovery efforts in the pharmaceutical industry for the treatment of type 2 diabetes mellitus (T2DM) and obesity, were initiated based on its restricted distribution in pancreas and GI tract, and its possible role in glucose homeostasis. While a number of lead series have emerged, the pharmacological endpoints they provide have not been clear. In particular, many lead series have demonstrated loss of efficacy and significant toxic side effects. Thus, we sought to identify novel, potent, positive modulators of GPR119. In this study, we have successfully developed and optimized a high-throughput screening strategy to identify GPR119 modulators using a live cell assay format that utilizes a cyclic nucleotide-gated channel as a biosensor for cAMP production. Our high-throughput screening (HTS) approach is unique to that of previous HTS approaches targeting this receptor, as changes in cAMP were measured both in the presence and absence of an EC₁₀ of the endogenous ligand, oleoylethanolamide, enabling detection of both agonists and potential allosteric modulators in a single assay. From these efforts, we have identified positive modulators of GPR119 with similar as well as unique scaffolds compared to existing compounds and similar as well as unique signaling properties. Our compounds will not only serve as novel molecular probes to better understand GPR119 pleiotropic signaling and the underlying physiological consequences of receptor activation, but are also well-suited for translation as potential therapeutic agents.

Effects of Drugs and Excipients on Hydration Status

Despite being the most essential nutrient, water is commonly forgotten in the fields of pharmacy and nutrition. Hydration status is determined by water balance (the difference between water input and output). Hypohydration or negative water balance is affected by numerous factors, either internal (i.e., a lack of thirst sensation) or external (e.g., polypharmacy or chronic consumption of certain drugs). However, to date, research on the interaction between hydration status and drugs/excipients has been scarce. Drugs may trigger the appearance of hypohydration by means of the increase of water elimination through either diarrhea, urine or sweat; a decrease in thirst sensation or appetite; or the alteration of central thermoregulation. On the other hand, pharmaceutical excipients induce alterations in hydration status by decreasing the gastrointestinal transit time or increasing the gastrointestinal tract rate or intestinal permeability. In the present review, we evaluate studies that focus on the effects of drugs/excipients on hydration status. These studies support the aim of monitoring the hydration status in patients, mainly in those population segments with a higher risk, to avoid complications and associated pathologies, which are key axes in both pharmaceutical care and the field of nutrition.

Assessment of counselling for acute diarrhoea in German pharmacies: a simulated patient study

OBJECTIVES

The aim of this study was to assess the quality of counselling provided for acute diarrhoea and to evaluate the role of the patient's approach and different user groups in determining the outcome of counselling.

METHODS

The simulated patient methodology was used in all 21 community pharmacies in a north-eastern German city. Four different scenarios related to self-medication of acute diarrhoea were developed and used in all the pharmacies (a total of 84 visits). The assessment form, completed immediately postvisit by the simulated patient, included 9 objective items scored using dichotomous scales to produce a scale from 0 to 9. After evaluating the data, every pharmacy received individual performance feedback to encourage behavioural changes and improve the quality of the counselling provided.

KEY FINDINGS

Overall, the quality of counselling was poor (mean score of 3.3/9 (37%)). The most common information provided was about dosage (87% of interactions), while the least common information given was about side effects (4% of interactions). The main effect was seen when comparing the product and symptom requests (F(1,60) = 24.748, P < 0.001, ωp2 = 0.277). There was no effect resulting from different user groups (F(1,28) = 0.237, P = 0.630, ωp2 = -0.026) and no interaction between the type of request and different user groups (F(1,28) = 3.395, P = 0.076, ωp2 = 0.073).

CONCLUSIONS

This study highlighted the current deficits in appropriate counselling provided by community pharmacies in Germany.

Spectrum of Drug-induced Chronic Diarrhea

The evaluation of a patient with chronic diarrhea can be quite frustrating, as it is expensive and involves multiple diagnostic studies. Moreover, identification of a drug as a cause of chronic diarrhea is a challenge in patients taking multiple medications. The disease may either be associated with intestinal mucosal changes, mimicking diseases such as celiac disease, or purely functional, with no histopathologic change. Drug-induced diarrhea may or may not be associated with malabsorption of nutrients, and a clinical improvement may occur within days of discontinuation of the drug, or may take longer when associated with mucosal injury. Diarrhea in diabetics, often attributed to poor management and lack of control, may be due to oral hypoglycaemic agents. Chemotherapy can result in diffuse or segmental colitis, whereas olmesartan and a few other medications infrequently induce a disease that mimics celiac disease, but is not associated with gluten intolerance. In short, increased awareness of a drug, as a cause for diarrhea and a clear understanding of the clinical manifestations will help clinicians to solve this challenging problem. This article aims to review drug-induced diarrhea to (a) understand known pathophysiological mechanisms; (b) assess the risk associated with frequently prescribed medications, and discuss the pathogenesis; and

The Comparative Pathology of Clostridium difficile-associated Disease

Clostridium difficile is a confirmed pathogen in a wide variety of mammals, but the incidence of disease varies greatly in relation to host species, age, environmental density of spores, administration of antibiotics, and possibly, other factors. Lesions vary as well, in severity and distribution within individuals, and in some instances, age groups, of a given species. The cecum and colon are principally affected in most species, but foals and rabbits develop severe jejunal lesions. Explanations for variable susceptibility of species, and age groups within a species, are largely speculative. Differences in colonization rates and toxin-receptor densities have been proposed. Clostridium difficile-associated disease is most commonly diagnosed in Syrian hamsters, horses, and neonatal pigs, but it is reported sporadically in many other species. The essential virulence factors of C. difficile are large exotoxins, toxin A (TcdA) and toxin B (TcdB). Receptor-mediated endocytosis of the toxins is followed by endosomal acidification, a necessary step for conversion of the toxin to its active form in the cytosol. Cell-surface receptors have been characterized for TcdA, but remain to be identified for TcdB. Both TcdA and TcdB disrupt the actin cytoskeleton by disrupting Rho-subtype, intracellular signaling molecules. Disruption of the actin cytoskeleton is catastrophic for cellular function, but inflammation and neurogenic stimuli are also involved in the pathogenesis of the disease.

Diacerein: Benefits, Risks and Place in the Management of Osteoarthritis. An Opinion-Based Report from the ESCEO

Diacerein is a symptomatic slow-acting drug in osteoarthritis (SYSADOA) with anti-inflammatory, anti-catabolic and pro-anabolic properties on cartilage and synovial membrane. It has also recently been shown to have protective effects against subchondral bone remodelling. Following the end of the revision procedure by the Pharmacovigilance Risk Assessment Committee of the European Medicines Agency, the European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis (ESCEO) constituted a panel of 11 experts to better define the real place of diacerein in the armamentarium for treating OA. Based on a literature review of clinical trials and meta-analyses, the ESCEO confirms that the efficacy of diacerein is similar to that of non-steroidal anti-inflammatory drugs (NSAIDs) after the first month of treatment, and superior to that of paracetamol. Additionally, diacerein has shown a prolonged effect on symptoms of several months once treatment was stopped. The use of diacerein is associated with common gastrointestinal disorders such as soft stools and diarrhoea, common mild skin reactions, and, uncommonly, hepatobiliary disorders. However, NSAIDs and paracetamol are known to cause potentially severe hepatic, gastrointestinal, renal, cutaneous and cardiovascular reactions. Therefore, the ESCEO concludes that the benefit-risk balance of diacerein remains positive in the symptomatic treatment of hip and knee osteoarthritis. Furthermore, similarly to other SYSADOAs, the ESCEO positions diacerein as a first-line pharmacological background treatment of osteoarthritis, particularly for patients in whom NSAIDs or paracetamol are contraindicated.

Enteral Nutrition for Adults in the Hospital Setting

In patients unable to tolerate oral intake, multiple options of nutrient delivery are available to the clinician. Administration of enteral nutrition (EN) has long been considered the standard of care for nutrition support among patients unable to meet energy and protein requirements orally. Healthcare practitioners must make careful decisions related to ordering, administering, and monitoring EN therapy. In the hospital setting, the registered dietitian is a key resource in enteral formula selection and method of administration, monitoring for and troubleshooting EN-related complications, and transitioning to oral feeding. The hospital setting also presents many unique challenges in providing optimal nutrition to the enterally fed patient.

Compartmentalized accumulation of cAMP near complexes of multidrug resistance protein 4 (MRP4) and cystic fibrosis transmembrane conductance regulator (CFTR) contributes to drug-induced diarrhea

Diarrhea is one of the most common adverse side effects observed in ∼7% of individuals consuming Food and Drug Administration (FDA)-approved drugs. The mechanism of how these drugs alter fluid secretion in the gut and induce diarrhea is not clearly understood. Several drugs are either substrates or inhibitors of multidrug resistance protein 4 (MRP4), such as the anti-colon cancer drug irinotecan and an anti-retroviral used to treat HIV infection, 3'-azido-3'-deoxythymidine (AZT). These drugs activate cystic fibrosis transmembrane conductance regulator (CFTR)-mediated fluid secretion by inhibiting MRP4-mediated cAMP efflux. Binding of drugs to MRP4 augments the formation of MRP4-CFTR-containing macromolecular complexes that is mediated via scaffolding protein PDZK1. Importantly, HIV patients on AZT treatment demonstrate augmented MRP4-CFTR complex formation in the colon, which defines a novel paradigm of drug-induced diarrhea.

Update on chronic diarrhea: a run-through for the clinician

Chronic diarrhea is a common patient complaint, with an estimated prevalence of 5 %. Diarrhea is defined as >200 g/day of stool with decreased consistency, and chronic diarrhea is defined as lasting more than 4 weeks. The purpose of this review is to guide the clinician's diagnostic evaluation and management of chronic diarrhea, rather than providing a textbook comprehensive review of the subject, focusing on the patient in developed countries and excluding the immune suppressed patient. While the investigation and treatment of chronic diarrhea can be challenging due to its myriad causes, when the clinician employs a practical approach, dividing chronic diarrhea into bloody, fatty, and watery causes, it simplifies and streamlines the work-up and management plan and leads to improved patient outcomes.

Drug-induced, factitious, & idiopathic diarrhoea

The aetiology of diarrhoea can often be simple to identify, but in some cases may pose a challenge. The diagnosis of drug-induced diarrhoea can easily be sorted based on timing of the symptom with onset of a new drug. Treatment can vary from simply monitoring and eventual resolution with continuation of the drug, to discontinuation of the offending agent. In cases where a drug cannot always be stopped, additional medications can help control the symptom. Factitious diarrhoea can present a diagnostic challenge if the evaluating physician does not suspect its possibility. Typically a careful history, and in some cases, stool testing can provide clues. The diagnosis of idiopathic diarrhoea is often made when exhaustive testing provides no definite aetiology and the goal of management is supportive care and symptomatic treatment.

Evaluating the patient with diarrhea: a case-based approach

The evaluation of the patient with diarrhea can be complex and the treatment challenging. In this article, the definition of diarrhea and the pathophysiologic mechanisms that lead to diarrhea are reviewed. A simplified 5-step approach to the patient with diarrhea is provided and applied in a case-oriented manner applicable to everyday clinical practice. On completion of this article, you should be able to (1) define diarrhea, (2) outline various pathophysiologic mechanisms of diarrhea, and (3) describe a simplified 5-step approach to facilitate the evaluation of diarrhea.

A case of cytomegalovirus colitis in an immunocompetent hemodialysis patient

Symptomatic cytomegalovirus (CMV) infection in immunocompetent patients has traditionally been considered to have a benign and self-limited course. Moreover, current concept is that CMV infection in immunocompetent patients does not require treatment. However, recent studies reveal that CMV infection in immunocompetent patient with clinical manifestation is not a rare condition as thought previously. Here, we report a case of CMV colitis, which occurred in an immunocompetent hemodialysis patient who neither had HIV infection nor had medication that could cause immunosuppression. Our case revealed that the conservative treatment was not enough, and the administration of ganciclovir was essential for improving the disease course.

Summary of the causative and treatment factors of diarrhea and the use of a diarrhea assessment and treatment tool to improve patient outcomes

This article is a review of the causative factors and pharmacologic treatments of diarrhea. This information was incorporated into a Diarrhea Assessment and Treatment Tool (DATT) to guide clinicians on comprehensive diarrhea assessment and current treatment recommendations. The tool was utilized at a university-affiliated oncology institution by a clinical nurse specialist on 26 patients as a performance improvement project. Ease of use and efficacy of DATT were tested. Eighty-one percent of patients were assessed using DATT in 30 minutes or less. Seventy-nine percent of the 57 identified diarrhea classifications were not being treated upon initial assessment. Diarrhea control was achieved in 73% of the patients within 7 days or fewer when DATT was utilized. The premise of diarrhea management is that if all the causative factors are not treated, diarrhea will persist. The conclusions are that this tool will aid the clinician in a comprehensive assessment of diarrhea and provide a systematic approach to diarrhea treatment. The need for research on best practice for management of the various causative factors of diarrhea is needed.

Drug-induced Injury of the Gastrointestinal Tract

The effects of drugs on the gastrointestinal tract are diverse and depend on numerous factors. Diagnosis is centered on histologic findings, with mostly nonspecific patterns of injury that must be interpreted in the correct clinical context. Nonsteroidal antiinflammatory drugs are a common cause of drug-induced gastrointestinal injury, with effects primarily in the gastric mucosa but also throughout the gastrointestinal tract. Another common class of drugs causing a variety of pathologic findings in the gut is chemotherapeutic agents. This article discusses the differential diagnosis of the various patterns of injury, including ischemic damage, and the histologic findings specific for certain drugs.

Recurrent cytomegalovirus colitis with megacolon in an immunocompetent elderly man

Gastrointestinal infection with cytomegalovirus (CMV) is uncommon in immunocompetent hosts. The case of a 70-year-old male with CMV colitis, who has no history of chronic inflammatory bowel disease or immunodeficiency is described. Diagnosis was aided by the identification of inclusion bodies that reacted positively for CMV by immunohistochemical testing in biopsy specimens from the colonic mucosa. His hospital course was characterized by poor improvement of his symptoms after the CMV infection was treated with ganciclovir, and the occurrence of megacolon. A repeat colonoscopy with biopsy revealed a recurrence of the CMV infection. Although CMV colitis is common in immunocompromised patients, we believe this is the first case of CMV colitis with megacolon and recurrent CMV infection in an immunocompetent patient. Colitis caused by CMV colitis should be considered in elderly people with diarrhea.

Gastrointestinal and liver side effects of drugs in elderly patients

It is expected that the percentage of people >60 years of age will be 22% worldwide by the year 2050. Multi-morbidity and poly-pharmacy are common in individuals during old age, while adverse drug reactions are at least twice as common in the elderly compared to younger adults. Publications related to drug side effects are rather rare in this age group since most clinical trials exclude patients >75-80 years of age. Gastrointestinal adverse drug reactions studied in the elderly include non-steroidal anti-inflammatory drugs (NSAIDs) and anticoagulant-induced gastrointestinal tract mucosal injuries. Malabsorption, diarrhoea and constipation are common side effects of laxatives, antibiotics, anticholinergics and calcium channel blockers. Drug (amoxycilin/clavulanic acid, isoniazide, nitrofurantoin, diclifenac and methotrexate)-induced hepatotoxicity in the elderly is four times more common than in younger adults and may simulate almost all known liver disorders. Further clinical studies are needed to investigate gastrointestinal and hepatic side effects of drugs in elderly patients.

Long Term Use of Leflunomide as a Cause of Severe Diarrhea?

Leflunomide is a recently developed disease modifying antirheumatic drug that may cause acute diarrhea as an adverse effect. This adverse effect is usually mild and develops during the first few weeks of treatment. In this report, we present a case of rheumatoid arthritis patient with severe diarrhea treated with leflunomide for an extended period of time. (Turk J Rheumatol 2010; 25: 41-3)

Diabetic diarrhea

Diabetic patients with diarrhea may present clinical challenges in diagnosis and treatment. Particular diagnoses are more prevalent in diabetic patients than in the general population. Medications are often a culprit for chronic diarrhea, and the medication list should always be carefully scrutinized for those with diarrhea as a side effect. In diabetic patients, metformin is a common cause of diarrhea. Diabetic patients are more likely to have associated diseases (eg, celiac sprue and microscopic colitis) that present with diarrhea as the sole complaint. Ingested sugar-free foods that may contain sorbitol or other agents can cause diarrhea in diabetic patients. Finally, diabetic enteropathy can itself cause diarrhea. The various etiologies can be diagnosed with a thorough history and appropriate diagnostic tests. This article focuses on the etiologies of diarrhea that are seen with higher incidence in diabetic patients.

Effects of bisacodyl on ascending colon emptying and overall colonic transit in healthy volunteers

BACKGROUND

The mechanism of action of bisacodyl in the unprepared human colon remains unclear.

AIM

To evaluate the effect of oral bisacodyl on the overall and regional colonic transit in humans.

METHODS

In a double-blind, randomized, placebo-controlled study of 25 healthy participants, effects of oral bisacodyl (5 mg p.o. per day) and placebo on colonic transit were compared. A validated scintigraphy method was used to measure colonic transit. The primary transit endpoints, ascending colon emptying t(1/2) and geometric centre of colon isotope at 24 h (overall transit), were compared (Wilcoxon rank sum test).

RESULTS

There were significant treatment effects on ascending colon t(1/2), with the bisacodyl group demonstrating accelerated emptying [median 6.5 h, interquartile range 5.0-8.0 h] relative to the placebo group [11.0 h (7.0-17.1); P = 0.03]. Numerical differences in colonic geometric centre 24 h [bisacodyl median 3.0 (2.2-3.8), placebo 4.0 (3.1-4.6)] were not significant (P = 0.19). There were no significant differences observed in geometric centre 4 h.

CONCLUSION

Oral 5 mg bisacodyl accelerates ascending colon in the unprepared colon in healthy adults; this action may contribute to the drug's efficacy in constipation.

Selective and brain penetrant neuropeptide y y2 receptor antagonists discovered by whole-cell high-throughput screening

The role of neuropeptide Y Y2 receptor (Y2R) in human diseases such as obesity, mood disorders, and alcoholism could be better resolved by the use of small-molecule chemical probes that are substantially different from the currently available Y2R antagonist, N-[(1S)-4-[(aminoiminomethyl)amino]-1-[[[2-(3,5-dioxo-1,2-diphenyl-1,2,4-triazolidin-4-yl)ethyl]amino]carbonyl]butyl]-1-[2-[4-(6,11-dihydro-6-oxo-5H-dibenz[b,e]azepin-11-yl)-1-piperazinyl]-2-oxoethyl]-cyclopentaneacetamide) (BIIE0246). Presented here are five potent, selective, and publicly available Y2R antagonists identified by a high-throughput screening approach. These compounds belong to four chemical scaffolds that are structurally distinct from the peptidomimetic BIIE0246. In functional assays, IC(50) values between 199 and 4400 nM against the Y2R were measured, with no appreciable activity against the related NPY-Y1 receptor (Y1R). Compounds also displaced radiolabeled peptide YY from the Y2R with high affinity (K(i) values between 1.55 and 60 nM) while not displacing the same ligand from the Y1R. In contrast to BIIE0246, Schild analysis with NPY suggests that two of the five compounds behave as competitive antagonists. Profiling against a panel of 40 receptors, ion channels, and transporters found in the central nervous system showed that the five Y2R antagonists demonstrate greater selectivity than BIIE0246. Furthermore, the ability of these antagonists to penetrate the blood-brain barrier makes them better suited for pharmacological studies of Y2R function in both the brain and periphery.

Diarrhea and malabsorption in the elderly

Acute and chronic diarrheal disorders are common problems at all ages. It has been estimated that 5% to 7% of the population has an episode of acute diarrhea each year and that 3% to 5% have chronic diarrhea that lasts more than 4 weeks. It is likely that the prevalence of diarrhea is similar in older individuals. This article reviews the impact of diarrhea in the elderly, many of whom are less fit physiologically to withstand the effect of diarrhea on fluid balance and nutritional balance.

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.

The prevalence of diarrhea and its association with drug use in elderly outpatients: a multicenter study

OBJECTIVES

To evaluate the prevalence of diarrhea and its association with drug use in elderly outpatients.

METHODS

The study was carried out by 133 general practitioners (GPs) who referred to 24 geriatric units in Italy. The demographic data, disability, gastrointestinal symptoms, and current medications were evaluated using a structured interview, including the evaluation of the activities of daily living (ADL), the instrumental activities of daily living (IADL), and the gastrointestinal symptoms rating scale (GSRS).

RESULTS

The study included 5,387 elderly subjects who regularly completed the structured interview. In total, 488 patients (9.1% of the whole population, 210 men and 278 women, mean age 75.6 +/- 6.2 yr, range 65-100 yr) reported diarrhea, that is, items 11 and 12 of the GSRS, during the 7-day period before the interview. The prevalence of diarrhea significantly increased with older age (P = 0.025), the severity of ADL (P < 0.0001) and IADL disability (P < 0.0001), and the number of drugs taken (P = 0.0002). A multivariate analysis demonstrated that the presence of diarrhea was significantly associated with the use of antibiotics (odds ratio [OR] 4.58, 95% confidence interval [CI] 1.95-10.73), proton pump inhibitors (OR 2.97, 95% CI 2.03-4.35), allopurinol (OR 2.19, 95% CI 1.26-3.81), psycholeptics (OR 1.82, 95% CI 1.26-2.61), selective serotonin reuptake inhibitors (OR 1.71, 95% CI 1.01-2.89), and angiotensin II receptor blockers (OR 1.46, 95% CI 1.08-1.99), also accounting for sex, age, and the use of antidiarrheal agents and drugs for functional gastrointestinal disorders.

CONCLUSION

Diarrhea is a common problem in elderly outpatients. Its prevalence increases with old age, the severity of disability, and the number of drugs. Monitoring the presence of diarrhea and its complications in elderly patients who need treatments with drugs significantly associated with diarrhea may be clinically useful.

Re-examination of risk factors for non-Clostridium difficile-associated diarrhoea in hospitalized patients

AIM

This paper is a report of a study to determine the incidence of non-Clostridium difficile-associated diarrhoea in hospitalized patients and to re-evaluate clinical characteristics and other risk factors related to non-C. difficile-associated diarrhoea.

BACKGROUND

Numerous factors are thought to be responsible for diarrhoea in hospitalized patients. Reports about the diarrhoeal effects of some medications administered concomitantly with tube feeding have stimulated reappraisal of the influence of tube feeding as a potential cause.

METHOD

This study was a secondary analysis of data of 154 hospitalized patients collected during a prospective epidemiological study from 1992 to 1993. The secondary analysis was completed in 2006 in order to investigate unanswered questions of current importance.

FINDINGS

The sample was predominantly male and middle aged; approximately 50% were tube fed, and 25% were in an intensive care unit. The incidence of diarrhoea was 35%. Increased severity of illness as well as the combination of sorbitol-containing medication administration and tube feeding were found to be statistically significant factors in the development of diarrhoea.

CONCLUSION

As diarrhoea in hospitalized patients appears to be multifactorial, use of an algorithm to systematically evaluate and manage related factors is recommended.

Xerostomia: clinical aspects and treatment

Xerostomia or dry mouth is a condition that is frequently encountered in dental practice. The most common cause is the use of certain systemic medications, which make the elderly at greater risk because they are usually more medicated. Other causes include high doses of radiation and certain diseases such as Sjogren's syndrome. Xerostomia is associated with difficulties in chewing, swallowing, tasting or speaking. This results in poor diet, malnutrition and decreased social interaction. Xerostomia can cause oral discomfort, especially for denture wearers. Patients are at increased risk of developing dental caries. A thorough intraoral and extra-oral clinical examination is important for diagnosis. Treatment may include the use of salivary substitutes (Biotene), salivary stimulants such as pilocarpine, ongoing dental care, caries prevention, a review of the current prescription drug regimen and possible elimination of drugs having anticholinergic effects. Because of the ageing population, and the concomitant increase in medicated individuals, dentists can expect to be presented with xerostomia in an increasing number of patients in the coming years and therefore should be familiar with its diagnosis and treatment. Therefore, the purpose of this review is to outline for clinicians the common aetiologies, clinical identification, and routine therapeutic modalities available for individuals with xerostomia.

History of Acid Suppression: Focus on the Hospital Setting

In the hospital setting, prophylactic acid suppression is an important part of care for many critically ill patients. It may also prevent rebleeding in patients admitted with acute upper gastrointestinal tract bleeding. Effective treatments for these conditions stemmed from our increased understanding of the gastric acid secretory pathway and target pH values. The late 1970s saw the introduction of histamine2-receptor antagonists (H2RAs), which partially suppress basal and meal-stimulated acid secretion. Some of these agents can induce an intragastric pH greater than 3, lasting for approximately 10 hours/day when given twice/day at recommended doses. This level of acid suppression can facilitate healing of duodenal ulcers but has limited efficacy for other indications (e.g., gastrointestinal bleed). In the late 1980s a more potent class of acid-suppressing agents was developed, proton pump inhibitors (PPIs). The PPIs can induce an intragastric pH above 3 lasting for approximately 17 hours/day, and an intragastric pH above 5 for approximately 9 hours/day after once-daily oral administration of recommended doses. It is possible to attain even higher target pH values with large doses and with continuous intravenous infusion. Thus, PPIs are agents of choice for treatment of many acid-related disorders including peptic ulcer disease and moderate-to-severe gastroesophageal reflux disease, and for prevention of rebleeding in patients with upper gastrointestinal bleeding. Availability of an intravenous formulation, pantoprazole, enables hospitalized patients for whom oral administration is not feasible to benefit from the superior potency of PPIs. Preliminary data suggest that intravenous PPIs may be more effective than H2RA prophylaxis against stress-related ulcer bleeding for intensive care patients and should facilitate healing in those with bleeding ulcers of the upper gastrointestinal tract.

[Antibiotic induced diarrhea and pseudomembranous colitis]

The spore-forming anaerobic bacterium Clostridium difficile has become a serious enteropathogen. Oral and parenteral administration of antibiotics can cause ecological disturbances in the normal intestinal microflora. Suppression of the normal microflora may lead to reduced colonization resistance with subsequent overgrowth by pre-existing, naturally resistant microorganisms, such as C. difficile. C. difficile infection shows a range of clinical presentations between an asymptomatic carrier state, light diarrhea without inflammatory changes, and pseudomembranous colitis. C. difficile infection is acquired by the fecal-oral or environmental-oral routes. From March 2000 through March 2001 we assessed 48 cases of nosocomial antibiotic-associated diarrhea (AAD). Of these, 21 were due to C. difficile (CDAD). Cephalosporin was the agent most commonly associated with CDAD. Avoidance of cephalosporins, strict use of "single shot" prophylaxis, isolation of infected, symptomatic patients in single-bed rooms, improved hygiene and complete room disinfection lead to a rapid decrease of CDAD. The etiology, prognosis and prophylaxis are discussed in this paper.

Small bowel disease in the elderly: diarrhoea and malabsorption

Diarrhoea and malabsorption are common problems in elderly persons. Worldwide, diarrhoea is the second leading cause of mortality. In the developed world, 85% of its mortality affects the elderly. The diagnostic work up for diarrhoea and malabsorption is more complex for the elderly than for the young patient. If diarrhoea persists for more than 24 h, oral rehydration solutions or intravenous fluids must be administered promptly in order to prevent hypotension and organ failure in the often multi-morbid patient. Both the immunocompromised patient and the severely affected out-patient should have stool culture performed. Malabsorption usually presents with weight loss, osteoporosis, anaemia, skin and neurological symptoms. The careful diagnostic work-up must aim at the identification of treatable disorders such as coeliac disease, Crohn's disease and bacterial overgrowth. Often, a detailed drug history is of help in identifying a readily treatable cause.

Diarrhea and malabsorption in the elderly

Physicians who care for elderly patients should be alert to the possible presence of diarrhea and malabsorption. Older patients may not admit to having chronic diarrhea, particularly if they also are incontinent. If diarrhea is of short duration, an infectious cause is at least as common as in the young. Institutionalized elderly are particularly prone to gastrointestinal infections, but the manifestations may not be overt. When an intestinal infection and potential medication-induced gastrointestinal disturbances have been excluded, the differential diagnosis of diarrhea in the elderly is the same as in the young. Causes include intestinal malabsorption, even though diarrhea is a less common manifestation of malabsorption in the old than in younger patients. In the elderly, micronutrient deficiency is a common presenting clinical picture; because the symptoms of malabsorption are covert, the diagnosis often is delayed, and nutritional deficiencies are more common and more severe than in the young. Because the elderly have less nutritional reserve than the young, these deficiencies are clinically much more devastating in the elderly. Although the causes of malabsorption, as a whole, are similar in older and younger patients, chronic pancreatic insufficiency of unknown cause and intestinal bacterial overgrowth without an anatomic abnormality of the small intestine are syndromes that are specific to the elderly and must be considered in any older patient with unexplained weight loss or failure to thrive. Often, therapeutic trials are necessary to establish a potential diagnosis.

Drug-induced diarrhoea

Diarrhoea is a relatively frequent adverse event, accounting for about 7% of all drug adverse effects. More than 700 drugs have been implicated in causing diarrhoea; those most frequently involved are antimicrobials, laxatives, magnesium-containing antacids, lactose- or sorbitol-containing products, nonsteroidal anti-inflammatory drugs, prostaglandins, colchicine, antineoplastics, antiarrhythmic drugs and cholinergic agents. Certain new drugs are likely to induce diarrhoea because of their pharmacodynamic properties; examples include anthraquinone-related agents, alpha-glucosidase inhibitors, lipase inhibitors and cholinesterase inhibitors. Antimicrobials are responsible for 25% of drug-induced diarrhoea. The disease spectrum of antimicrobial-associated diarrhoea ranges from benign diarrhoea to pseudomembranous colitis. Several pathophysiological mechanisms are involved in drug-induced diarrhoea: osmotic diarrhoea, secretory diarrhoea, shortened transit time, exudative diarrhoea and protein-losing enteropathy, and malabsorption or maldigestion of fat and carbohydrates. Often 2 or more mechanisms are present simultaneously. In clinical practice, 2 major types of diarrhoea are seen: acute diarrhoea, which usually appears during the first few days of treatment, and chronic diarrhoea, lasting more than 3 or 4 weeks and which can appear a long time after the start of drug therapy. Both can be severe and poorly tolerated. In a patient presenting with diarrhoea, the medical history is very important, especially the drug history, as it can suggest a diagnosis of drug-induced diarrhoea and thereby avoid multiple diagnostic tests. The clinical examination should cover severity criteria such as fever, rectal emission of blood and mucus, dehydration and bodyweight loss. Establishing a relationship between drug consumption and diarrhoea or colitis can be difficult when the time elapsed between the start of the drug and the onset of symptoms is long, sometimes up to several months or years.