The use of erythromycin as a gastrointestinal prokinetic agent in adult critical care: benefits versus risks

Antibiotic erythromycin in fish: Pharmacokinetics, effects, and health risks

Erythromycin is a macrolide antibiotic commonly utilized in veterinary medicine and aquaculture. It functions by binding to the 50S subunit of 70S ribosomes, inhibiting protein synthesis and effectively treating numerous bacterial diseases. Due to the extensive use of erythromycin, it has been detected in various aquatic systems in recent years. Multiple studies have reported the occurrence of erythromycin resistance and its adverse effects on diverse aquatic organisms. Consequently, potential environmental health risks associated with erythromycin have garnered increasing attention. As an integral component of aquatic ecosystems, fish have been the subject of numerous reports regarding the bioaccumulation and adverse effects of erythromycin; however, these data have not been collated and interpreted. This report provides a comprehensive overview of the environmental fate of erythromycin, detection methods, pharmacokinetics, and impacts on fish. In addition to the therapeutic benefits against pathogens, acute or chronic exposure of fish to erythromycin at concentrations ranging from μg/L to mg/L disrupts the primary defense, antioxidant, and xenobiotic metabolism systems, leading to oxidative stress, cellular structural damage, and metabolic disorders, manifesting as cytotoxicity, organ toxicity, neurotoxicity, developmental toxicity, and reproductive toxicity. However, further in-depth studies are warranted to evaluate the therapeutic efficacy at relatively high levels, particularly when considering pathogens with developed resistance to erythromycin, as well as the long-term effects of erythromycin exposure at environmentally relevant concentrations in fish, thereby better assessing the health risks posed by erythromycin to fish and their consumers humans.

Decoding the structural basis of ligand recognition and biased signaling in the motilin receptor

The motilin receptor (MTLR) is a key target for treating gastrointestinal (GI) disorders like gastroparesis, yet developing effective agonists remains challenging due to drug tolerance and signaling bias. We present cryoelectron microscopy (cryo-EM) structures of MTLR bound to azithromycin, a macrolide antibiotic, and DS-3801b, a non-macrolide agonist. Distinct ligand recognition mechanisms are revealed, with azithromycin binding deeply within the orthosteric pocket and DS-3801b adopting a special clamp-like conformation stabilized by a water molecule. We also highlight the critical role of extracellular loop 2 (ECL2) in ligand specificity and signaling pathway activation, affecting both G-protein and β-arrestin signaling. Additionally, the "D2.60R2.63S3.28" motif and interactions around transmembranes 6/7 (TM6/7) are identified as key drivers of signaling selectivity. These findings offer insights into the structural dynamics of MTLR, laying the groundwork for the rational design of next-generation GI prokinetic drugs with enhanced efficacy and safety.

Gastric ultrasound to assess the prokinetic efficacy of erythromycin in a patient taking glucagon-like peptide-1 receptor agonists

Glucagon-like peptide-1 receptor agonists slow gastric emptying and may increase aspiration risk. Recent guidelines suggest using prokinetic agents pre-operatively, but no studies have assessed the efficacy of erythromycin for this purpose. We present a 53-year-old man (weight 110 kg) taking liraglutide and undergoing elective knee arthroscopy. Despite 19 h of fasting and withholding liraglutide, gastric ultrasound revealed a grade 3 antrum with solid content. Intravenous erythromycin 300 mg was administered, causing transient gastrointestinal symptoms. A repeat ultrasound 15 min later showed reduced solid content, although the antrum was not convincingly empty. As the patient declined neuraxial anaesthesia without sedation, a modified rapid sequence induction was performed. An ultrasound scan at the completion of surgery confirmed an empty stomach, and recovery was uneventful. This is the first documented case using gastric ultrasound to assess the effect of erythromycin on a patient taking a glucagon-like peptide-1 receptor agonist. While erythromycin achieved its desired effect within 100 min, the optimal timing for prokinetic administration and subsequent ultrasound assessment remains uncertain. Gastric ultrasound may refine risk stratification and guide prokinetic use for these patients. Further research is needed to determine optimal erythromycin dosing, time to desired effect and side effects to optimise peri-operative management.

Prokinetic effect of erythromycin in the management of gastroparesis in critically ill patients-our experience and literature review

Introduction

Gastroparesis is a disorder characterized by impaired gastric emptying and the accumulation of food in the intestines without any clear mechanical cause. Gastroparesis in critical care patients is a prevalent issue in the intensive care unit. The disruption of normal gastrointestinal motility in critically ill patients is linked to a significant risk of intolerance to enteral feeding, colonization of the gastrointestinal tract with pathogenic bacterial strains, increased permeability of the intestinal wall, translocation of the intestinal microbiota, leading to progressive malnutrition, and potential development of bacterial infection.

Materials and methods

The literature was reviewed to assess the benefits and risks associated with the use of this medication.

Aim

The aim of the study was to treat the symptoms of gastroparesis and stimulate gastrointestinal motility. Consequently, the aim was to reduce the amount of backed-up food content in the stomach, accelerate gastrointestinal motility, and return to intestinal feeding.

Results

Gastroparesis is a frequent issue among patients in the intensive care unit. Critical illness can lead to gastrointestinal motility disorders, causing slowed gastric emptying. This increases the risk of problems such as intolerance to enteral feeding, regurgitation, and aspiration of gastrointestinal contents into the respiratory tract, as well as colonization of the gastrointestinal tract by pathogens. Over time, impaired intestinal absorption can result in malnutrition, necessitating the initiation of parenteral nutrition.

Conclusion

After analysis of the literature and published scientific reports, as well as considering their own research, it is evident that erythromycin, as a prokinetic drug, effectively enhances gastrointestinal motility. This contributes to stimulating gastric emptying in critically ill patients with gastroparesis who are hospitalized in an intensive care unit. The use of erythromycin in combination with metoclopramide and/or itopride hydrochloride allows for a synergistic effect, leading to the quickest possible return to enteral feeding.

Measurement and Analysis of In Vivo Gastroduodenal Slow Wave Patterns Using Anatomically-Specific Cradles and Electrodes

OBJECTIVE

Bioelectrical 'slow waves' regulate gastrointestinal contractions. We aimed to confirm whether the pyloric sphincter demarcates slow waves in the intact stomach and duodenum.

METHODS

We developed and validated novel anatomically-specific electrode cradles and analysis techniques which enable high-resolution slow wave mapping across the in vivo gastroduodenal junction. Cradles housed flexible-printed-circuit and custom cradle-specific electrode arrays during acute porcine experiments (N = 9; 44.92 kg ± 8.49 kg) and maintained electrode contact with the gastroduodenal serosa. Simultaneous gastric and duodenal slow waves were filtered independently after determining suitable organ-specific filters. Validated algorithms calculated slow wave propagation patterns and quantitative descriptions.

RESULTS

Butterworth filters, with cut-off frequencies (0.0167 - 2) Hz and (0.167 - 3.33) Hz, were optimal filters for gastric and intestinal slow wave signals, respectively. Antral slow waves had a frequency of (2.76 ± 0.37) cpm, velocity of (4.83 ± 0.21) mm·s-1, and amplitude of (1.13 ± 0.24) mV, before terminating at the quiescent pylorus that was (46.54 ± 5.73) mm wide. Duodenal slow waves had a frequency of (18.13 ± 0.56) cpm, velocity of (11.66 ± 1.36) mm·s-1, amplitude of (0.32 ± 0.03) mV, and originated from a pacemaker region (7.24 ± 4.70) mm distal to the quiescent zone.

CONCLUSION

Novel engineering methods enable measurement of in vivo electrical activity across the gastroduodenal junction and provide qualitative and quantitative definitions of slow wave activity.

SIGNIFICANCE

The pylorus is a clinical target for a range of gastrointestinal motility disorders and this work may inform diagnostic and treatment practices.

Antimicrobial use and opportunities for antimicrobial stewardship in pediatric postacute and long-term care settings

We performed a point-prevalence study of antimicrobial prescriptions in 9 pediatric postacute and long-term care (pPALTC) settings. Antimicrobials were prescribed for 5%-7% of residents including infectious (41%), noninfectious (24%), prophylaxis (24%), and unknown (11%) indications. Macrolides were often prescribed for noninfectious indications. Developing treatment guidelines are antimicrobial stewardship opportunities for pPALTC.

Polyketides as Secondary Metabolites from the Genus Aspergillus

Polyketides are an important class of structurally diverse natural products derived from a precursor molecule consisting of a chain of alternating ketone and methylene groups. These compounds have attracted the worldwide attention of pharmaceutical researchers since they are endowed with a wide array of biological properties. As one of the most common filamentous fungi in nature, Aspergillus spp. is well known as an excellent producer of polyketide compounds with therapeutic potential. By extensive literature search and data analysis, this review comprehensively summarizes Aspergillus-derived polyketides for the first time, regarding their occurrences, chemical structures and bioactivities as well as biosynthetic logics.

Erythromycin prior to endoscopy for acute upper gastrointestinal haemorrhage

BACKGROUND

Upper endoscopy is the definitive treatment for upper gastrointestinal haemorrhage (UGIH). However, up to 13% of people who undergo upper endoscopy will have incomplete visualisation of the gastric mucosa at presentation. Erythromycin acts as a motilin receptor agonist in the upper gastrointestinal (GI) tract and increases gastric emptying, which may lead to better quality of visualisation and improved treatment effectiveness. However, there is uncertainty about the benefits and harms of erythromycin in UGIH.

OBJECTIVES

To evaluate the benefits and harms of erythromycin before endoscopy in adults with acute upper gastrointestinal haemorrhage, compared with any other treatment or no treatment/placebo.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search date was 15 October 2021.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that investigated erythromycin before endoscopy compared to any other treatment or no treatment/placebo before endoscopy in adults with acute UGIH.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were 1. UGIH-related mortality and 2. serious adverse events. Our secondary outcomes were 1. all-cause mortality, 2. visualisation of gastric mucosa, 3. non-serious adverse events, 4. rebleeding, 5. blood transfusion, and 5. rescue invasive intervention. We used GRADE criteria to assess the certainty of the evidence for each outcome.  MAIN RESULTS: We included 11 RCTs with 878 participants. The mean age ranged from 53.13 years to 64.5 years, and most participants were men (72.3%). One RCT included only non-variceal haemorrhage, one included only variceal haemorrhage, and eight included both aetiologies. We defined short-term outcomes as those occurring within one week of initial endoscopy. Erythromycin versus placebo Three RCTs (255 participants) compared erythromycin with placebo. There were no UGIH-related deaths. The evidence is very uncertain about the short-term effects of erythromycin compared with placebo on serious adverse events (risk difference (RD) -0.01, 95% confidence interval (CI) -0.04 to 0.02; 3 studies, 255 participants; very low certainty), all-cause mortality (RD 0.00, 95% CI -0.03 to 0.03; 3 studies, 255 participants; very low certainty), non-serious adverse events (RD 0.01, 95% CI -0.03 to 0.05; 3 studies, 255 participants; very low certainty), and rebleeding (risk ratio (RR) 0.63, 95% CI 0.13 to 2.90; 2 studies, 195 participants; very low certainty). Erythromycin may improve gastric mucosa visualisation (mean difference (MD) 3.63 points on 16-point ordinal scale, 95% CI 2.20 to 5.05; higher MD means better visualisation; 2 studies, 195 participants; low certainty). Erythromycin may also result in a slight reduction in blood transfusion (MD -0.44 standard units of blood, 95% CI -0.86 to -0.01; 3 studies, 255 participants; low certainty). Erythromycin plus nasogastric tube lavage versus no intervention/placebo plus nasogastric tube lavage Six RCTs (408 participants) compared erythromycin plus nasogastric tube lavage with no intervention/placebo plus nasogastric tube lavage. There were no UGIH-related deaths and no serious adverse events. The evidence is very uncertain about the short-term effects of erythromycin plus nasogastric tube lavage compared with no intervention/placebo plus nasogastric tube lavage on all-cause mortality (RD -0.02, 95% CI -0.08 to 0.03; 3 studies, 238 participants; very low certainty), visualisation of the gastric mucosa (standardised mean difference (SMD) 0.48 points on 10-point ordinal scale, 95% CI 0.10 to 0.85; higher SMD means better visualisation; 3 studies, 170 participants; very low certainty), non-serious adverse events (RD 0.00, 95% CI -0.05 to 0.05; 6 studies, 408 participants; very low certainty), rebleeding (RR 1.13, 95% CI 0.63 to 2.02; 1 study, 169 participants; very low certainty), and blood transfusion (MD -1.85 standard units of blood, 95% CI -4.34 to 0.64; 3 studies, 180 participants; very low certainty). Erythromycin versus nasogastric tube lavage Four RCTs (287 participants) compared erythromycin with nasogastric tube lavage. There were no UGIH-related deaths and no serious adverse events. The evidence is very uncertain about the short-term effects of erythromycin compared with nasogastric tube lavage on all-cause mortality (RD 0.02, 95% CI -0.05 to 0.08; 3 studies, 213 participants; very low certainty), visualisation of the gastric mucosa (RR 1.19, 95% CI 0.79 to 1.79; 2 studies, 198 participants; very low certainty), non-serious adverse events (RD -0.10, 95% CI -0.34 to 0.13; 3 studies, 213 participants; very low certainty), rebleeding (RR 0.77, 95% CI 0.40 to 1.49; 1 study, 169 participants; very low certainty), and blood transfusion (median 2 standard units of blood, interquartile range 0 to 4 in both groups; 1 study, 169 participants; very low certainty). Erythromycin plus nasogastric tube lavage versus metoclopramide plus nasogastric tube lavage One RCT (30 participants) compared erythromycin plus nasogastric tube lavage with metoclopramide plus nasogastric tube lavage. The evidence is very uncertain about the effects of erythromycin plus nasogastric tube lavage on all the reported outcomes (serious adverse events, visualisation of gastric mucosa, non-serious adverse events, and blood transfusion).

AUTHORS' CONCLUSIONS

We are unsure if erythromycin before endoscopy in people with UGIH has any clinical benefits or harms. However, erythromycin compared with placebo may improve gastric mucosa visualisation and result in a slight reduction in blood transfusion.

Evaluation of the Pharmacokinetics of Trazpiroben (TAK-906), a Peripherally Selective D2/D3 Dopamine Receptor Antagonist, in the Presence and Absence of Itraconazole, a Potent CYP 3A4 Inhibitor

Purpose

Treatment options for gastroparesis, such as metoclopramide and domperidone, are limited because of safety concerns, which may be exacerbated in the presence of inhibitors of drug metabolism. This study evaluated the effect of itraconazole on the pharmacokinetics, safety, and tolerability of trazpiroben (previously TAK-906), a novel, peripherally selective D₂/D₃ dopamine receptor antagonist.

Methods

This was a phase 1, two-period, crossover trial in healthy participants (NCT03161405). On day 1, period 1 (days 1–3), participants received a single oral dose of trazpiroben 25 mg. During period 2 (days 4–9), participants received oral itraconazole 200 mg once daily (days 1–5) and one oral dose of trazpiroben 25 mg post itraconazole on day 4. Trazpiroben pharmacokinetics were assessed. Safety assessments included triplicate electrocardiograms.

Results

Twelve healthy males (24–45 years old) were studied. Co-administration of itraconazole increased trazpiroben area under the concentration–time curve from time 0 to infinity by 1.28-fold (90% confidence interval: 1.10, 1.49) and maximum plasma concentration (C_max) by 1.98-fold (1.64, 2.39) versus trazpiroben alone. Placebo-corrected, change from baseline in corrected QT interval at the observed geometric mean C_max for trazpiroben alone (9.53 ng/mL) and with itraconazole (18.00 ng/mL) was estimated at 1.31 ms (−0.39, 3.01) and 1.54 ms (−0.15, 3.24), respectively. There were no clinically relevant abnormalities in any safety parameters.

Conclusion

These results indicate that TAK‑906 is relatively insensitive to inhibition of cytochrome P450 3A4, and cardiovascular safety concerns associated with domperidone are unlikely to be elicited by trazpiroben under similar conditions.

Erythromycin versus metoclopramide for post-pyloric spiral nasoenteric tube placement: a randomized non-inferiority trial

Purpose

To determine whether erythromycin is non-inferior to metoclopramide in facilitating post-pyloric placement of self-propelled spiral nasoenteric tubes (NETs) in critically ill patients.

Methods

A prospective, multicenter, open-label, parallel, and non-inferiority randomized controlled trial was conducted comparing erythromycin with metoclopramide in facilitating post-pyloric placement of spiral NETs in critically ill patients admitted to intensive care units (ICUs) of eight tertiary hospitals in China. The primary outcome was procedure success defined as post-pyloric placement (spiral NETs reached the first portion of the duodenum or beyond confirmed by abdominal radiography 24 h after tube insertion).

Results

A total of 5688 patients were admitted to the ICUs. Of these, in 355 patients there was a plan to insert a nasoenteric feeding tube, of whom 332 were randomized, with 167 patients assigned to the erythromycin group and 165 patients assigned to the metoclopramide group. The success rate of post-pyloric placement was 57.5% (96/167) in the erythromycin group, as compared with 50.3% (83/165) in the metoclopramide group (a difference of 7.2%, 95% CI − 3.5% to 17.9%), in the intention-to-treat analysis, not including the prespecified margin of − 10% for non-inferiority. The success rates of post-D1 (reaching the second portion of the duodenum or beyond), post-D2 (reaching the third portion of the duodenum or beyond), post-D3 (reaching the fourth portion of the duodenum or beyond), and proximal jejunum placement and the incidence of any adverse events were not significantly different between the groups.

Conclusions

Erythromycin is non-inferior to metoclopramide in facilitating post-pyloric placement of spiral NETs in critically ill patients. The success rates of post-D1, post-D2, post-D3, and proximal jejunum placement were not significantly different.

Noninvasive Magnetogastrography Detects Erythromycin-Induced Effects on the Gastric Slow Wave

OBJECTIVE

The prokinetic action of erythromycin is clinically useful under conditions associated with gastrointestinal hypomotility. Although erythromycin is known to affect the electrogastrogram, no studies have examined the effects that erythromycin has on gastric slow wave magnetic fields.

METHODS

In this study, gastric slow wave activity was assessed simultaneously using noninvasive magnetogastrogram (MGG), electrogastrogram, and mucosal electromyogram recordings. Recordings were obtained for 30 min prior to and 60 min after intravenous administration of erythromycin at dosages of 3 and 6 mg/kg.

RESULTS

MGG recordings showed significant changes in the percentage power distribution of gastric signal after infusion of both 3 and 6 mg/kg erythromycin at t = 1-5 min that persisted for t = 30-40 min after infusion. These changes agree with the changes observed in the electromyogram. We did not observe any statistically significant difference in MGG amplitude before or after injection of either 3 or 6 mg/kg erythromycin. Both 3 and 6 mg/kg erythromycin infusion showed retrograde propagation with a statistically significant decrease in slow wave propagation velocity 11-20 min after infusion. Propagation velocity started returning toward baseline values after approximately 21-30 min for the 3 mg/kg dosage and after 31-40 min for a dosage of 6 mg/kg.

CONCLUSION

Our results showed that the magnetic signatures were sensitive to disruptions in normal slow wave activity induced by pharmacological and prokinetic agents such as erythromycin.

SIGNIFICANCE

This study shows that repeatable noninvasive bio-electro-magnetic techniques can objectively characterize gastric dysrhythmias and may quantify treatment efficacy in patients with functional gastric disorders.

Cardiovascular safety of prokinetic agents: A focus on drug-induced arrhythmias

BACKGROUND

Gastrointestinal sensorimotor dysfunction underlies a wide range of esophageal, gastric, and intestinal motility and functional disorders that collectively constitute nearly half of all referrals to gastroenterologists. As a result, substantial effort has been dedicated toward the development of prokinetic agents intended to augment or restore normal gastrointestinal motility. However, the use of several clinically efficacious gastroprokinetic agents, such as cisapride, domperidone, erythromycin, and tegaserod, is associated with unfavorable cardiovascular safety profiles, leading to restrictions in their use.

PURPOSE

The purpose of this review is to detail the cellular and molecular mechanisms that lead commonly to drug-induced cardiac arrhythmias, specifically drug-induced long QT syndrome, torsades de pointes, and ventricular fibrillation, to examine the cardiovascular safety profiles of several classes of prokinetic agents currently in clinical use, and to explore potential strategies by which the risk of drug-induced cardiac arrhythmia associated with prokinetic agents and other QT interval prolonging medications can be mitigated successfully.

Etiology and functional validation of gastrointestinal motility dysfunction in a zebrafish model of CHARGE syndrome

CHARGE syndrome is linked to autosomal-dominant mutations in the CHD7 gene and results in a number of physiological and structural abnormalities, including heart defects, hearing and vision loss, and gastrointestinal (GI) problems. Of these challenges, GI problems have a profound impact throughout an individual's life, resulting in increased morbidity and mortality. A homolog of CHD7 has been identified in the zebrafish, the loss of which recapitulates many of the features of the human disease. Using a morpholino chd7 knockdown model complemented by a chd7 null mutant zebrafish line, we examined GI structure, innervation, and motility in larval zebrafish. Loss of chd7 resulted in physically smaller GI tracts with normal epithelial and muscular histology, but decreased and disorganized vagal projections, particularly in the foregut. chd7 morphant larvae had significantly less ability to empty their GI tract of gavaged fluorescent beads, and this condition was only minimally improved by the prokinetic agents, domperidone and erythromycin, in keeping with mixed responses to these agents in patients with CHARGE syndrome. The conserved genetics and transparency of the zebrafish have provided new insights into the consequences of chd7 gene dysfunction on the GI system and cranial nerve patterning. These findings highlight the opportunity of the zebrafish to serve as a preclinical model for studying compounds that may improve GI motility in individuals with CHARGE syndrome.

Erythromycin for Promoting the Postpyloric Placement of Feeding Tubes: A Systematic Review and Meta-Analysis

Background

Critically ill patients can benefit from enteral nutrition with postpyloric feeding tubes, but the low success rate limits its wide use. Erythromycin could elevate the success rate of tube insertion, but its clinical efficiency still remains controversial.

Methods

Included studies must be RCTs which assessed the success rate of postpyloric feeding tube insertion using erythromycin.

Results

284 patients were enrolled in six studies. Meta-analysis showed that erythromycin significantly increases the rate of successful postpyloric feeding tube placement (RR 1.45, 95% CI (1.12, 1.86)) and did not increase the risk of adverse effects (RR 2.15, 95% CI (0.20, 22.82)). Subgroup analysis showed that unweighted feeding tubes (RR 1.47, 95% CI (1.03, 2.11)) could significantly increase the success rate. Country of study, intravenous route of erythromycin, and year of participant enrollment did not influence these results.

Conclusions

Erythromycin significantly increases the success rate of postpyloric feeding tube placement. This suggests that erythromycin can be used as an auxiliary method to improve the success rate of bedside insertion.

Gastrointestinal dysmotility in critically ill patients

Gastrointestinal (GI) motility disorders are commonly present in critical illness. Up to 60% of critically ill patients have been reported to experience GI dysmotility of some form necessitating therapeutic intervention. It has been attributed to various factors, related to both the underlying disease and the therapeutic interventions undertaken. The assessment of motility disturbances can be challenging in critically ill patients, as the available tests used to detect abnormal motility have major limitations in the setting of an Intensive Care Unit. Critically ill patients with GI dysmotility require a multifaceted treatment approach that addresses multiple causes and utilizes multiple pharmacological pathways. In this review, we discuss the pathophysiology, assessment and management of GI dysmotility in critically ill patients.

[Treatment of postoperative impairment of gastrointestinal motility, cholangitis and pancreatitis]

Although the mortality associated with major hepatopancreaticobiliary surgery has continuously decreased during the last decades, the morbidity of these procedures remains high. Functional disturbances of normal gastrointestinal motility as well as inflammation and infections of surgically treated organs are frequent complications resulting in considerably prolonged lengths of stay in hospital and increased healthcare costs. This review article highlights the therapeutic approaches and recent developments in the treatment of delayed gastric emptying, prolonged postoperative ileus, postoperative cholangitis and pancreatitis after hepatopancreaticobiliary surgery. Current practice is discussed on the basis of recent results in basic and clinical research, review articles, meta-analyses and guidelines.

Gastrointestinal dysmotility disorders in critically ill dogs and cats

OBJECTIVE

To review the human and veterinary literature regarding gastrointestinal (GI) dysmotility disorders in respect to pathogenesis, patient risk factors, and treatment options in critically ill dogs and cats.

ETIOLOGY

GI dysmotility is a common sequela of critical illness in people and small animals. The most common GI motility disorders in critically ill people and small animals include esophageal dysmotility, delayed gastric emptying, functional intestinal obstruction (ie, ileus), and colonic motility abnormalities. Medical conditions associated with the highest risk of GI dysmotility include mechanical ventilation, sepsis, shock, trauma, systemic inflammatory response syndrome, and multiple organ failure. The incidence and pathophysiology of GI dysmotility in critically ill small animals is incompletely understood.

DIAGNOSIS

A presumptive diagnosis of GI dysmotility is often made in high-risk patient populations following detection of persistent regurgitation, vomiting, lack of tolerance of enteral nutrition, abdominal pain, and constipation. Definitive diagnosis is established via radioscintigraphy; however, this diagnostic tool is not readily available and is difficult to perform on small animals. Other diagnostic modalities that have been evaluated include abdominal ultrasonography, radiographic contrast, and tracer studies.

THERAPY

Therapy is centered at optimizing GI perfusion, enhancement of GI motility, and early enteral nutrition. Pharmacological interventions are instituted to promote gastric emptying and effective intestinal motility and prevention of complications. Promotility agents, including ranitidine/nizatidine, metoclopramide, erythromycin, and cisapride are the mainstays of therapy in small animals.

PROGNOSIS

The development of complications related to GI dysmotility (eg, gastroesophageal reflux and aspiration) have been associated with increased mortality risk. Institution of prophylaxic therapy is recommended in high-risk patients, however, no consensus exists regarding optimal timing of initiating prophylaxic measures, preference of treatment, or duration of therapy. The prognosis for affected small animal patients remains unknown.

The antibiotic azithromycin is a motilin receptor agonist in human stomach: comparison with erythromycin

BACKGROUND AND PURPOSE

The antibiotic azithromycin is a suggested alternative to erythromycin for treating patients with delayed gastric emptying. However, although hypothesized to activate motilin receptors, supportive evidence is unavailable. This was investigated using recombinant and naturally expressed motilin receptors in human stomach, comparing azithromycin with erythromycin.

EXPERIMENTAL APPROACH

[(125)I]-motilin binding and calcium flux experiments were conducted using human recombinant motilin receptors in CHO cells. Neuromuscular activities were studied using circular muscle of human gastric antrum, after electrical field stimulation (EFS) of intrinsic nerves.

KEY RESULTS

Azithromycin (1-100 μM) and erythromycin (3-30 μM) concentration-dependently displaced [(125)I]-motilin binding to the motilin receptor (52 ± 7 and 58 ± 18% displacement at 100 and 30 μM respectively). Azithromycin, erythromycin and motilin concentration-dependently caused short-lived increases in intracellular [Ca(2+)] in cells expressing the motilin receptor. EC50 values were, respectively, 2.9, 0.92 and 0.036 μM (n = 3 each); and maximal activities were similar. In human stomach, EFS evoked cholinergically mediated contractions, attenuated by simultaneous nitrergic activation. Azithromycin and erythromycin lactobionate (30-300 μM each) facilitated these contractions (apparent E(max) values of 2007 ± 396 and 1924 ± 1375%, n = 3-4 each concentration, respectively). These actions were slow in onset and faded slowly. The higher concentrations also evoked short-lived muscle contraction. Contractions to a submaximally effective concentration of carbachol were unaffected by either drug.

CONCLUSIONS AND IMPLICATIONS

Azithromcyin activates human recombinant motilin receptors in therapeutically relevant concentrations, similar to erythromycin. In humans, gastric antrum azithromycin caused long-lasting facilitation of cholinergic activity. These actions explain the gastric prokinetic activity of azithromycin.

Prokinetic drugs for gastric emptying in critically ill ventilated patients: Analysis through breath testing

PURPOSE

The prupose was to identify, through the BreathID automatic breath-testing device, the best prokinetic therapy to enhance gastric-emptying rate (GER) in ventilated intensive care unit patients.

MATERIALS AND METHODS

This was a prospective, crossover, nonrandomized study. Consecutive ventilated patients who could be fed enterally and expected to require 5 days of ventilation were included. (13)C-labeled-acetate in 100 mL Osmolite (BreathID; Exalenz Bioscience Ltd, Jerusalem, Israel) was administered intragastrically and followed by a 4-hour continuous recording of expiratory (13)CO2 by the BreathID. Prokinetics were changed daily: (1) baseline (no prokinetic), (2) intravenous (IV) metoclopramide (10 mg every 6 hours), (3) IV metoclopramide (10 mg every 6 hours) and continuous low-dose erythromycin (10 mg/h), (4) IV continuous low-dose erythromycin alone (10 mg/h), and (5) IV bolus erythromycin (200 mg every 12 hours). Gastric-emptying rate was assessed by the percentage dose recovered (PDR)-change from time 0 of the recording in the ratio of (13)CO2/(12)CO2 in exhaled gases (%/h). We used PDR peak values and time to peak (minutes to reach PDR peak) to express GER.

RESULTS

In the first 17 patients (group A), baseline GER measurements preceded prokinetic therapy. In the subsequent 14 patients (group B), 2 prokinetic regimens preceded baseline. No order-time effect was observed, justifying pooled analysis of all 31 patients. Combined metoclopramide-continuous low-dose erythromycin yielded significantly higher PDR peak and shorter time to peak vs baseline (P = .0001, P = .005, respectively). The PDR peak was also significantly higher from baseline during continuous low-dose administration of erythromycin alone (P = .004). Metoclopramide alone did not improve GER significantly.

CONCLUSIONS

Combined metoclopramide-continuous low-dose erythromycin was found to be the best protocol in the current study to increase GER in ventilated patients. It should be tested as a first-line prokinetic therapy in ventilated patients with poor gastric emptying in further randomized controlled studies. The breath-test device presented in this study can be a user-friendly and practical method to monitor GER, enabling individual tailoring of prokinetic therapy. Further studies to explore its utility are warranted.

Non-anti-infective effects of antimicrobials and their clinical applications: a review

Antimicrobial agents are undoubtedly one of the key advances in the history of modern medicine and infectious diseases, improving the clinical outcomes of infection owing to their inhibitory effects on microbial growth. However, many antimicrobial agents also have biological activities stemming from their interactions with host receptors and effects on host inflammatory responses and other human or bacterial cellular biological pathways. These result in clinical uses of antimicrobial drugs that are distinct from their direct bacteriostatic or bactericidal properties. We reviewed the published literature regarding non-anti-infective therapeutic properties and proposed clinical applications of selected antimicrobials, specifically, macrolides, tetracyclines, sulfonamides, and ketoconazole. The clinical applications reviewed were varied, and we focused on uses that were clinically relevant (in terms of importance and burden of disease) and where published evidence exists. Such uses include chronic inflammatory pulmonary and skin disorders, chronic periodontitis, gastrointestinal dysmotility, rheumatoid arthritis, and cancer. Most of these potential therapeutic uses are not Food and Drug Administration approved. Clinicians need to weigh the use of antimicrobial agents for their non-anti-infective benefits, considering potential adverse effects and long-term effect on microbial resistance.

Current issues on safety of prokinetics in critically ill patients with feed intolerance

Feed intolerance in the setting of critical illness should be treated promptly given its adverse impact on morbidity and mortality. The technical difficulty of postpyloric feeding tube placement and the morbidities associated with parenteral nutrition prevent these approaches being considered as first-line nutrition. Prokinetic agents are currently the mainstay of therapy for feed intolerance in the critically ill. Current information is limited but suggests that erythromycin or metoclopramide (alone or in combination) are effective in the management of feed intolerance in the critically ill and not associated with significant cardiac, haemodynamic or neurological adverse effects. However, diarrhoea is a very common gastrointestinal side effect, and can occur in up to 49% of patients who receive both erythromycin and metoclopramide. Fortunately, the diarrhoea associated with prokinetic treatments has not been linked to Clostridium difficile infection and settles soon after the drugs are ceased. Therefore, prolonged or prophylactic use of prokinetics should be avoided. If diarrhoea occurs, the drugs should be stopped immediately. To minimize avoidable adverse effects the ongoing need for prokinetic drugs in these patient should be reviewed daily.

Drugs acting at 5-HT4 , D2 , motilin, and ghrelin receptors differ markedly in how they affect neuromuscular functions in human isolated stomach

BACKGROUND

Progress in identifying safer, effective drugs to increase gastric emptying is impeded by failed clinical trials. One potential reason for failure is lack of translation from animal models to the human condition. To make progress, the actions of existing drugs and new therapeutic candidates need to be understood in human isolated stomach.

METHODS

Neuromuscular activities were evoked in human gastric antrum circular muscle by electrical field stimulation (EFS), defined phenotypically using pharmacological tools.

KEY RESULTS

EFS evoked cholinergically mediated contractions, attenuated by simultaneous nitrergic activation. The 5-HT4 receptor agonist/D2 antagonist metoclopramide and the selective 5-HT4 agonist prucalopride, facilitated contractions in the absence (respectively, Emax 95 ± 29% and 42 ± 9%, n = 3-6 each concentration) and presence (139 ± 38%, 55 ± 13%, n = 3-5) of the NO synthase inhibitor L-NAME, without affecting submaximal contractions to carbachol; the 5-HT4 antagonist SB204070 prevented facilitation by metoclopramide 100 μM (respectively, -5 (range -26 to 34) and 167 (12-1327)% in presence and absence; n = 5-6). The selective motilin receptor agonist camicinal provided considerably greater facilitation (478 (12-2080)% at 30 μM, n = 8). Domperidone (0.001-100 μM; n = 3-6) and acylated or des-acylated ghrelin (1-300 nM; n = 2-4) had no consistent activity, even with protease inhibitors.

CONCLUSIONS & INFERENCES

5-HT4 receptor agonists show different efficacies. Motilin receptor activation has greater potential to increase gastric emptying, whereas ghrelin and D2 receptor antagonism have no direct activity. Drugs stimulating human gastric motility directly can act regardless of disease mechanisms, whereas drugs without direct activity but an ability to block nausea/vomiting may be effective only if these symptoms exist.

Motilin: towards a new understanding of the gastrointestinal neuropharmacology and therapeutic use of motilin receptor agonists

The gastrointestinal hormone motilin has been known about for >40 years, but after identification of its receptor and subsequent development of new tools and methods, a reappraisal of its actions is required. Firstly, it is important to note that motilin and ghrelin receptors are members of the same family (similar genomic organization, gastrointestinal distribution and abilities to stimulate gastrointestinal motility), yet each fails to recognize the ligand of the other; and whereas ghrelin and ghrelin receptors are widespread outside the gastrointestinal tract, motilin and its receptors are largely restricted to the gastrointestinal tract. Secondly, although some studies suggest motilin has activity in rodents, most do not, and receptor pseudogenes exist in rodents. Thirdly, motilin preferentially operates by facilitating enteric cholinergic activity rather than directly contracting the muscle, despite the relatively high expression of receptor immunoreactivity in muscle. This activity is ligand-dependent, with short-lasting actions of motilin contrasting with longer-lasting actions of the non-selective and selective motilin receptor agonists erythromycin and GSK962040. Finally, the use of erythromycin (also an antibiotic drug) to treat patients requiring acceleration of gastric emptying has led to concerns over safety and potential exacerbation of antibiotic resistance. Replacement motilin receptor agonists derived from erythromycin (motilides) have been unsuccessful. New, non-motilide, small molecule receptor agonists, designed to minimize self-desensitization, are now entering clinical trials for treating patients undergoing enteral feeding or with diabetic gastroparesis. Thus, for the translational pharmacologist, the study of motilin illustrates the need to avoid overreliance on artificial systems, on structural information and on animal studies.

LINKED ARTICLES

This article is part of a themed section on Neuropeptides. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2013.170.issue-7.

Review article: the role of gastrointestinal hormones in the treatment of delayed gastric emptying in critically ill patients

BACKGROUND

Delayed gastric emptying limits the administration of enteral nutrition, leading to malnutrition, which is associated with higher mortality and morbidity. Currently available prokinetics have limitations in terms of sustained efficacy and side effects.

AIM

To summarise the mechanisms of action and to discuss the possible utility of gastrointestinal hormones to prevent or treat delayed gastric emptying in critically ill patients.

METHODS

We searched PubMed for articles discussing 'delayed gastric emptying', 'enteral nutrition', 'treatment', 'gastrointestinal hormones', 'prokinetic', 'agonist', 'antagonist' and 'critically ill patients'.

RESULTS

Motilin and ghrelin receptor agonists initiate the migrating motor complex in the stomach, which accelerates gastric emptying. Cholecystokinin, glucagon-like peptide-1 and peptide YY have an inhibiting effect on gastric emptying; therefore, antagonising these gastrointestinal hormones may have therapeutic potential. Other gastrointestinal hormones appear less promising.

CONCLUSIONS

Manipulation of endogenous secretion, physiological replacement and administration of gastrointestinal hormones in pharmacological doses is likely to have therapeutic potential in the treatment of delayed gastric emptying. Future challenges in this field will include the search for candidates with improved selectivity and favourable kinetic properties.

Antibiotics acting as neuroprotectants via mechanisms independent of their anti-infective activities

This review considers available evidence that some antibiotics have ancillary neuroprotective effects. Notably, β-lactam antibiotics are believed to increase the expression of glutamate transporter GLT1, potentially relieving the neurological excitotoxicity that characterizes disorders like amyotrophic lateral sclerosis. Minocycline has shown promise in reducing the severity of a number of neurological diseases, including multiple sclerosis, most likely by reducing apoptosis and the expression of inflammatory mediators in the brain. Rapamycin inhibits the activity of a serine/threonine protein kinase that has a role in the pathogenesis of numerous neurologic diseases. Herein we examine the unique neuroprotective aspects of these drugs originally developed as anti-infective agents.

Risks of population antimicrobial resistance associated with chronic macrolide use for inflammatory airway diseases

Macrolide antibiotics have established efficacy in the management of cystic fibrosis and diffuse panbronchiolitis-uncommon lung diseases with substantial morbidity and the potential for rapid progression to death. Emerging evidence suggests benefits of maintenance macrolide treatment in more indolent respiratory diseases including chronic obstructive pulmonary disease and non-cystic fibrosis bronchiectasis. In view of the greater patient population affected by these disorders (and potential for macrolide use to spread to disorders such as chronic cough), widespread use of macrolides, particularly azithromycin, has the potential to substantially influence antimicrobial resistance rates of a range of respiratory microbes. In this Personal View, I explore theories around population (rather than patient) macrolide resistance, appraise evidence linking macrolide use with development of resistance, and highlight the risks posed by injudicious broadening of their use, particularly of azithromycin. These risks are weighed against the potential benefits of macrolides in less aggressive inflammatory airway disorders. A far-sighted approach to maintenance macrolide use in non-cystic fibrosis inflammatory airway diseases is needed, which minimises risks of adversely affecting community macrolide resistance: combining preferential use of erythromycin and restriction of macrolide use to those patients at greatest risk represents an appropriately cautious management approach.

Macrolide therapy in chronic inflammatory diseases

Macrolides are a group of antibiotics with a distinctive macrocyclic lactone ring combined with sugars (cladinose, desosamine). The action of macrolides is to block protein synthesis by binding to the subunit of 50S ribosome of bacteria. Prototype macrolide was erythromycin, which came into clinical practice in the 50s of the 20th century. Its antimicrobial spectrum covers the scope of the penicillins but is extended to the impact of atypical bacteria. In the 90s more drugs of this group were synthesized—they have less severe side effects than erythromycin, extended spectrum of Gram-negative bacteria. Macrolides are effective in treating mycobacterial infections especially in patients infected with HIV. It is now known that in addition to antibacterial abilities, macrolides have immunomodulatory effects—they inhibit the production of proinflammatory cytokines (TNF, IL1, 6, and 8) affect transcription factors (NF-κB) as well as costimulaton (CD 80) and adhesion molecules (ICAM). This review article focused not only on the their antimicrobial abilities but also on efficacy in the treatment of several inflammatory disorders independent of the infectious agent. Their wider use as immunomodulators requires further study, which can lead to an extension of indications for their administration.

Motility disorders of the upper gastrointestinal tract in the intensive care unit: pathophysiology and contemporary management

Upper gastrointestinal (GI) dysmotility, an entity commonly found in the intensive care unit setting, can lead to insufficient nutrient intake while increasing the risk of infection and mortality. Further, overcoming the altered motility with early enteral feeding is associated with a reduced incidence of infectious complications in intensive care unit patients. Upper GI dysmotility in critical care patients is a common occurrence, and there are many causes for this problem, which affects a very heterogenous population with a multitude of underlying medical abnormalities. Therefore, it is of utmost importance to identify this widespread problem and subsequently institute a proper therapy as rapidly as possible. Prokinetic pharmacotherapies are currently the mainstay for the management of disordered upper GI motility. Future therapies, aimed at the underlying pathophysiology of this complex problem, are under investigation. These aim is to reduce the side effects of the currently available options, while improving on nutrition delivery in the critically ill. This review discusses the pathophysiology, clinical manifestations, diagnosis, and treatment of upper GI motility disturbances in the critically ill.

Efficacy of intermediate-dose oral erythromycin on very low birth weight infants with feeding intolerance

BACKGROUND

Erythromycin is generally used as a prokinetic agent for the treatment of feeding intolerance in preterm infants; however, results from previous studies significantly vary due to different medication dosages, routes of administration, and therapy durations. The effectiveness and safety of intermediate-dose oral erythromycin in very low birth weight (VLBW) infants with feeding intolerance was examined in this study.

METHODS

Between November 2007 and August 2009, 45 VLBW infants with feeding intolerance, who were all at least 14 days old, were randomly allocated to a treatment group and administered 5mg/kg oral erythromycin every 6hours for 14 days (n=19). Another set of randomly selected infants was allocated to the control group, which was not administered erythromycin (n=26).

RESULTS

The number of days required to achieve full enteral feeding (36.5±7.4 vs. 54.7±23.3 days, respectively; p=0.01), the duration of parenteral nutrition (p<0.05), and the time required to achieve a body weight ≥2500g (p<0.05) were significantly shorter in the erythromycin group compared with the control group. The incidence of parenteral nutrition-associated cholestasis (PNAC) and necrotizing enterocolitis (NEC) ≥ stage II after 14 days of treatment were significantly lower (p<0.05) in the erythromycin group. No significant differences were observed in terms of the incidences of sepsis, bronchopulmonary dysplasia, or retinopathy of prematurity. No adverse effects were associated with erythromycin treatment.

CONCLUSIONS

Intermediate-dose oral erythromycin is effective and safe for the treatment of feeding intolerance in VLBW infants. The incidences of PNAC and ≥ stage II NEC were significant lower in the erythromycin group.

GSK962040: a small molecule motilin receptor agonist which increases gastrointestinal motility in conscious dogs

BACKGROUND

GSK962040, a small molecule motilin receptor agonist, was identified to address the need for a safe, efficacious gastric prokinetic agent. However, as laboratory rodents lack a functional motilin system, studies in vivo have been limited to a single dose, which increased defecation in rabbits. Motilin agonists do not usually increase human colonic motility, so gastric prokinetic activity needs to be demonstrated.

METHODS

The effect of intravenous GSK962040 on gastro-duodenal motility was assessed in fasted dogs implanted with strain gauges. Activity was correlated with blood plasma concentrations of GSK962040 (measured by HPLC-MS/MS) and potency of GSK962040 at the dog recombinant receptor [using a Fluorometric Imaging Plate Reader (Molecular Devices, Wokingham, UK) after expression in HEK293 cells].

KEY RESULTS

GSK962040 activated the dog motilin receptor (pEC(50) 5.79; intrinsic activity 0.72, compared with [Nle(13) ]-motilin). In vivo, GSK962040 induced phasic contractions, the duration of which was dose-related (48 and 173 min for 3 and 6 mg kg(-1) ), driven by mean plasma concentrations >1.14 μmol L(-1) . After the effects of GSK962040 faded, migrating motor complex (MMC) activity returned. Migrating motor complex restoration was unaffected by 3 mg kg(-1) GSK962040 but at 6 mg kg(-1) , MMCs returned 253 min after dosing, compared with 101 min after saline (n=5 each).

CONCLUSIONS & INFERENCES

The results are consistent with lower potency for agonists at the dog motilin receptor, compared with humans. They also define the doses of GSK962040 which stimulate gastric motility. Correlation of in vivo and in vitro data in the same species, together with plasma concentrations, guides further studies and translation to other species.

Use of multicriteria decision analysis to support weight of evidence evaluation

Weight of evidence (WOE) methods are key components of ecological and human health risk assessments. Most WOE applications rely on the qualitative integration of diverse lines of evidence (LOE) representing impact on ecological receptors and humans. Recent calls for transparency in assessments and justifiability of management decisions are pushing the community to consider quantitative methods for integrated risk assessment and management. This article compares and contrasts the type of information required for application of individual WOE techniques and the outcomes that they provide in ecological risk assessment and proposes a multicriteria decision analysis (MCDA) framework for integrating individual LOE in support of management decisions. The use of quantitative WOE techniques is illustrated for a hypothetical but realistic case study of selecting remedial alternatives at a contaminated aquatic site. Use of formal MCDA does not necessarily eliminate biases and judgment calls necessary for selecting remedial alternatives, but allows for transparent evaluation and fusion of individual LOE. It also provides justifiable methods for selecting remedial alternatives consistent with stakeholder and decision-maker values.

Preclinical electrogastrography in experimental pigs

Surface electrogastrography (EGG) is a non-invasive means of recording gastric myoelectric activity or slow waves from cutaneous leads placed over the stomach. This paper provides a comprehensive review of preclinical EGG. Our group recently set up and worked out the methods for EGG in experimental pigs. We gained our initial experience in the use of EGG in assessment of porcine gastric myoelectric activity after volume challenge and after intragastric administration of itopride and erythromycin. The mean dominant frequency in pigs is comparable with that found in humans. EGG in experimental pigs is feasible. Experimental EGG is an important basis for further preclinical projects in pharmacology and toxicology.

Meta-analysis: erythromycin before endoscopy for acute upper gastrointestinal bleeding

BACKGROUND

Studies evaluating the effect of erythromycin on patients with acute upper gastrointestinal bleeding (UGIB) had been reported, but the results were inconclusive.

AIMS

To compare erythromycin with control in patients with acute UGIB by performing a meta-analysis.

METHODS

Electronic databases including PubMed, EMBASE and the Cochrane Library, Science Citation Index, were searched to find relevant randomised controlled trials (RCTs). Two reviewers independently identified relevant trials evaluating the effect of erythromycin on patients with acute UGIB. Outcome measures were the incidence of empty stomach, need for second endoscopy, blood transfusion, length of hospital stay, endoscopic procedure time and mortality.

RESULTS

Four RCTs including 335 patients were identified. Meta-analysis demonstrated the incidence of empty stomach was significantly increased in patients receiving erythromycin (active group 69%, control group 37%, P<0.00001). The need for second endoscopy, amount of blood transfusion and the length of hospital stay were also significantly reduced (all P<0.05). A trend for shorter endoscopic procedure time and decreased mortality rate was observed.

CONCLUSIONS

Prophylactic erythromycin is useful for patients with upper gastrointestinal bleeding to decrease the amount of blood in the stomach and reduce the need for second endoscopy, amount of blood transfusion. It may shorten the length of hospital stay, but its effects on mortality need further larger trials to be confirmed.

Diabetic gastroparesis: Therapeutic options

Gastroparesis is a condition characterized by delayed gastric emptying and the most common known underlying cause is diabetes mellitus. Symptoms include nausea, vomiting, abdominal fullness, and early satiety, which impact to varying degrees on the patient's quality of life. Symptoms and deficits do not necessarily relate to each other, hence despite significant abnormalities in gastric emptying, some individuals have only minimal symptoms and, conversely, severe symptoms do not always relate to measures of gastric emptying. Prokinetic agents such as metoclopramide, domperidone, and erythromycin enhance gastric motility and have remained the mainstay of treatment for several decades, despite unwanted side effects and numerous drug interactions. Mechanical therapies such as endoscopic pyloric botulinum toxin injection, gastric electrical stimulation, and gastrostomy or jejunostomy are used in intractable diabetic gastroparesis (DG), refractory to prokinetic therapies. Mitemcinal and TZP-101 are novel investigational motilin receptor and ghrelin agonists, respectively, and show promise in the treatment of DG. The aim of this review is to provide an update on prokinetic and mechanical therapies in the treatment of DG.

Drug-induced acute liver failure and gastrointestinal complications

The objective of this article is to describe adverse drug events related to the liver and gastrointestinal tract in critically ill patients. PubMed and other resources were used to identify information related to drug-induced acute liver failure, gastrointestinal hypomotility, constipation, diarrhea, gastrointestinal bleeding, and pancreatitis in critically ill patients. This information was reviewed, and data regarding pathophysiology, common drug causes, and guidelines for prevention and management were collected and summarized. In cases in which data in critically ill patients were unavailable, data were extrapolated from other patient populations. Drug-induced acute liver failure can be caused by many drugs routinely used in the intensive care unit and may be associated with significant morbidity and mortality. Drug-related hypomotility and constipation and drug-related diarrhea are reported with many drugs, and these are common adverse drug events in critically ill patients that can substantially complicate the care of these patients. Drug-induced gastrointestinal bleeding and drug-induced pancreatitis occur less frequently, can range in disease severity, and can be associated with morbidity and mortality. Many drugs used in critically ill patients are associated with adverse drug events related to the liver and gastrointestinal tract. Critical care clinicians should be aware of common drug causes of drug-induced acute liver failure, gastrointestinal hypomotility, constipation, diarrhea, gastrointestinal bleeding, and pancreatitis, and should be familiar with the prevention and management of these diverse conditions.

Current and future therapeutic prokinetic therapy to improve enteral feed intolerance in the ICU patient

Malnutrition is associated with poor outcomes in critically ill patients, and providing enteral feeding to those who cannot eat is considered best practice. Enteral feeding is often unsuccessful when there is delayed gastric emptying. Recent research has given additional insight into the mechanisms underlying delayed gastric emptying. Pharmacological strategies to improve the success of feeding include prokinetic drugs such as metoclopramide and erythromycin alone or in combination. When drug treatment fails, either parenteral nutrition or direct small intestinal feeding is indicated. Simpler methods to access the duodenum and distal small bowel for feed delivery are under investigation. This review summarizes current understanding of the mechanisms underlying enteral feeding intolerance in critical illness, together with the evidence for current treatment practices. Areas requiring further research are also described.

Disparate response to metoclopramide therapy for gastric feeding intolerance in trauma patients with and without traumatic brain injury

Patients with traumatic brain injury (TBI) have delayed gastric emptying and often require prokinetic drug therapy to improve enteral feeding tolerance. The authors hypothesized that metoclopramide was less efficacious for improving gastric feeding tolerance for trauma patients with TBI compared to trauma patients without TBI. A retrospective analysis was conducted of patients admitted to the trauma or neurosurgical intensive care unit who received gastric feeding from January 2006 to April 2008. Gastric feeding intolerance was defined by a gastric residual volume >200 mL or emesis with abdominal distension or discomfort. Patients with gastric feeding intolerance were given metoclopramide 10 mg intravenously every 6 hours, followed by a dose escalation to 20 mg, and then combination therapy with metoclopramide and erythromycin 250 mg intravenously every 6 hours if intolerance persisted. In total, 882 trauma patients (49% with TBI) were evaluated. TBI patients had a higher incidence of gastric feeding intolerance than those without TBI (18.6% vs 10.4%, P < or = .001). Efficacy rates for metoclopramide 10 mg, metoclopramide 20 mg, and metoclopramide-erythromycin were 55%, 62%, and 79%, respectively (P < or = .03). Metoclopramide failure occurred in 54% of patients with TBI compared to 35% of patients without TBI, respectively (P < or = .02), due to a greater prevalence of tachyphylaxis. Single-drug therapy with metoclopramide was less effective for TBI trauma patients compared to trauma patients without TBI. Combination therapy with erythromycin as first-line therapy for TBI trauma patients with gastric feeding intolerance is indicated if there are no contraindications or significant drug interactions.

[Promotility drugs use in critical care: indications and limits?]

Enteral feeding is often limited by gastric and intestinal motility disturbances in critically ill patients, particularly in patients with shock. So, promotility agents are frequently used to improve tolerance to enteral nutrition. This review summaries the pathophysiology, presents the available pharmacological strategies, the clinical data, the counter-indications and the principal limits. The clinical data are poor. No study demonstrates a positive effect on clinical outcomes. Metoclopramide and erythromycin seems to be the more effective. Considering the risk of antibiotic resistance, the first line use of erythromycin should be avoided in favor of metoclopramide.

[Enteral feeding of critical patients]

Artificial nutrition support forms part of the basic care of critical patients. Enteral feeding has been shown to be better than total parenteral nutrition at improving morbidity (infectious complications) and reducing the length of hospital stays, number of days with mechanical ventilation, and costs. As with any other treatment, enteral feeding has associated complications and side effects which should be understood and treated in order to obtain the greatest benefit from it and reduce possible adverse effects. In this review, we attempt to provide a practical summary of the use of enteral feeding in critical patients. We cover the management of the most frequent associated complications, based on new studies and current scientific evidence. The review is intended to serve as a practice guide for the routine care of severely ill patients.