Changes in pyloric resistance induced by erythromycin

Gastrointestinal Motility Disorders in the Neonate

Gastrointestinal (GI) motility disorders in term and premature infants may occur at different times of gestation. Knowledge of normal neuromuscular development can help clinicians determine the cause of GI dysmotility and prognosis in infants born with congenital anomalies. Various developmental abnormalities and premature gestational age can alter normal GI motility, requiring further advanced testing and management. A multidisciplinary approach is often needed to care for these patients.

Macrolides for the prevention and treatment of feeding intolerance in preterm low birth weight infants: a systematic review and meta-analysis

The role of macrolides for the prevention and treatment of feeding intolerance (FI) in preterm low birth weight (LBW) infants has not been well established. To assess the efficacy and safety of macrolides to prevent or treat FI in preterm LBW infants. A systematic review and meta-analysis (PROSPERO ID: CRD42020170519) was conducted for English articles published since inception to March 2020, using MEDLINE, EMBASE, and the Cochrane Controlled Trials Register. Search terms included preterm low birth weight infants, macrolides, erythromycin, azithromycin, clarithromycin, and feeding intolerance. Randomized controlled trials (RCTs) assessing the effects of macrolide therapy on the time to achieve full enteral feeding (FEF;150 mL/kg/day), duration of parenteral nutrition (PN), hospitalization, and adverse events in preterm LBW infants were included. Independent extraction of data was done by both authors using predefined data-sheet. Very-low to low-quality evidence from 21 RCTs, 19 for erythromycin (prophylaxis-6, rescue-13) and 2 for clarithromycin (prophylaxis-1, rescue-1) demonstrated a significantly beneficial role of erythromycin for an earlier FEF, both as a prophylaxis (SMD-0.53, 95% CI - 0.74,- 0.33; 6 studies, n = 368) as well as rescue (SMD-1.16, 95% CI - 1.88, - 0.44; 11 studies, n = 664). Rescue therapy was also beneficial for a significant reduction in the duration of PN, hospitalization, incidences of sepsis, necrotizing enterocolitis, and cholestasis. No arrhythmia or infantile hypertrophic pyloric stenosis was reported.Conclusions: Erythromycin therapy, both as prophylaxis and rescue, is beneficial to reduce the time to achieve FEF in preterm LBW infants, at no higher risk of adverse events.Trial registration: PROSPERO ID: CRD42020170519.

Effect of amoxicillin/clavulanate on gastrointestinal motility in children

AIM

The aim of the present study was to evaluate the effect of amoxicillin/clavulanate (A/C) on gastrointestinal motility.

METHODS

Twenty consecutive pediatric patients referred for antroduodenal manometry received 20 mg/kg of A/C into the small bowel lumen. In 10 patients (group A), A/C was given 1 hour after and in 10 (group B), 1 hour before ingestion of a meal. Characteristics of the migrating motor complex, including presence, frequency, amplitude, and propagation of duodenal phase III and phase I duration and phase II motility index (MI), were evaluated 30 minutes before and after A/C administration.

RESULTS

There were no statistically significant differences in age and sex between the 2 groups. Manometry studies were considered normal in 8 patients in each group. In group A, 2 patients developed duodenal phase III after receiving A/C, and no significant difference was found in the MI before and after the drug administration. In group B, 9 patients developed duodenal phase III (P <0.05 vs group A). All phase III occurred within a few minutes from the medication administration. Most duodenal phase III contractions were preceded by an antral component during fasting but never after the medication was administered in either of the 2 groups (P<0.001 vs fasting). In group B, the duration of duodenal phase I was shorter after drug administration (P<0.05). There was no significant difference in duodenal phase II MI before and after A/C administration for the 2 study groups.

CONCLUSIONS

In children, administration of A/C directly into the small bowel before a meal induces phase III-type contractions in the duodenum, with characteristics similar to those present in the fasting state. These data suggest the possible use of A/C as a prokinetic agent. Further studies are needed to clarify its specific mechanism of action and the group of patients most likely to benefit from its use.

Use of prokinetics in the preterm infant

PURPOSE OF REVIEW

Functional gastrointestinal dysmotility is a common condition that affects premature infants. Delay in achievement of full enteral nutrition results in dependence on prolonged parenteral nutrition, predisposing to adverse outcomes. Studies in recent years show apparently conflicting results regarding the use of prokinetic agents in preterm infants. This review aims to evaluate these studies to determine whether use of these agents in premature infants is beneficial and justified.

RECENT FINDINGS

Randomized controlled trials in recent years have been performed to investigate the effectiveness of erythromycin in the treatment of nonobstructive gastrointestinal dysmotility in preterm infants. Overall, neither low-dose regimes nor prophylactic trials have been shown to be useful. High-dose regimes used as rescue therapy of infants with established gastrointestinal dysmotility have consistently shown clinical benefit. Theoretical risks of prolonged antibiotic use, such as emergence of antibiotic resistance and abnormal intestinal microbiota, have not been fully evaluated.

SUMMARY

Judicious use of high-dose erythromycin in premature infants as rescue therapy is probably justifiable. Further research in this area is warranted to develop newer prokinetic agents which may improve the safety profile of therapy.

Long-term tegaserod treatment for dysmotility-like functional dyspepsia: results of two identical 1-year cohort studies

BACKGROUND

Functional dyspepsia (FD) is a chronic disorder that adversely affects health-related quality of life (HRQoL). Published information on its long-term management is minimal and treatment options are limited.

AIM

The aim of this study was to evaluate safety, efficacy and HRQoL with tegaserod 6 mg twice daily over 1 year in women with FD who completed one of two 6-week, randomized, placebo-controlled, double-blind studies.

METHODS

About 780 patients received tegaserod 6 mg twice daily in two identical 1-year extension studies. Scheduled assessments included adverse events, the Short-Form Nepean Dyspepsia Index (SF-NDI), Work Productivity and Activity Impairment-Dyspepsia (WPAI-Dyspepsia) questionnaire, and patient perceptions of treatment efficacy.

RESULTS

Mean tegaserod treatment duration in the two studies was 236 and 222 days. Most adverse events occurred in the first 6 months, were similar to previous reports (commonly diarrhea), and were transient and well tolerated. SF-NDI, WPAI-Dyspepsia scores and perceived symptom relief improved from baseline over the 1-year evaluation.

CONCLUSIONS

The long-term safety profile of tegaserod in women with FD was consistent with that of short-term treatment and accompanied by improvements in HRQoL, work productivity and symptom relief. These long-term results add to the clinical experience with FD and support the potential value of a 5-HT(4) agonist in the management of FD.

5-HT and the brain-gut axis: opportunities for pharmacologic intervention

Interactions between the enteric nervous system of the gut and the brain occur bidirectionally over sympathetic and parasympathetic pathways. Coordinated actions of the central, autonomic and enteric nervous systems modulate intestinal motor, sensory and secretory activities by neuromodulators, including 5-HT, noradrenaline and dopamine. 5-HT is an important signaling molecule in the brain-gut axis and the 5-HT released from enterochromaffin cells modulates peristaltic, secretory, vasodilatory, vagal and nociceptive reflexes. Irritable bowel syndrome is associated with altered motility, secretion and sensation; enteric 5-HT signaling may be defective in this disorder. In this editorial, recent data are reviewed and the potential for the development of pharmacologic intervention is assessed.

High-dose oral erythromycin decreased the incidence of parenteral nutrition-associated cholestasis in preterm infants

BACKGROUND & AIMS

Feeding intolerance because of functional gastrointestinal dysmotility and parenteral nutrition-associated cholestasis (PNAC) are common problems in preterm, very-low-birth-weight (VLBW) infants. This double-blind, randomized, placebo-controlled study aimed to assess the effectiveness of "high-dose" oral erythromycin as a prokinetic agent in decreasing the incidence of PNAC. Two secondary end points, including the time to achieve full enteral feeding and the duration of parenteral nutrition, were also evaluated.

METHODS

Infants consecutively admitted to the neonatal unit were randomized to receive erythromycin (12.5 mg/kg/dose every 6 hours for 14 days) or an equivalent volume of normal saline (placebo) if they attained less than half the total daily fluid intake (<75 mL/kg/day) as milk feeds on day 14 of life.

RESULTS

Of 182 VLBW infants enrolled, 91 received erythromycin. The incidence of PNAC was significantly lower in erythromycin-treated infants (18/91) compared with placebo infants (37/91; P = .003). Treated infants achieved full enteral nutrition significantly earlier (mean, 10.1; SE, 1.7 days; P < .001), and the duration of parenteral nutrition was also significantly decreased by 10 days (P < .001). Importantly, fewer infants receiving erythromycin had 2 or more episodes of septicemia (n = 4) compared with placebo patients (n = 13, P = .03). No serious adverse effect was associated with erythromycin treatment.

CONCLUSIONS

High-dose oral erythromycin can be considered as a rescue measure for VLBW infants who fail to establish adequate enteral nutrition and in whom anatomically obstructive pathologies of the gastrointestinal tract have been excluded.

Tegaserod is effective in the initial and retreatment of irritable bowel syndrome with constipation

BACKGROUND

Symptoms of irritable bowel syndrome are often cyclical and thus may require repeated rather than continuous therapy. Tegaserod is effective and well-tolerated for irritable bowel syndrome with constipation but data on retreatment are lacking.

AIM

To assess whether tegaserod retreatment is as efficacious and well-tolerated as initial treatment in a primary care setting.

METHODS

This open-label trial was designed to evaluate the effectiveness of tegaserod under real-life conditions. Irritable bowel syndrome with constipation patients received tegaserod 6 mg b.d. for 12 weeks; response was assessed at weeks 4 and 12. Responders (those achieving satisfactory relief for at least 2 of the previous 4 weeks) at weeks 4 and/or 12 entered an 8-week withdrawal period where symptom recurrence was assessed. Patients experiencing recurrence could receive tegaserod 6 mg b.d. for another 4 weeks (retreatment phase) and on completion, could choose to continue tegaserod in a 6-month extension study.

RESULTS

A total of 513 patients received initial treatment with tegaserod; 85.0% (436 of 513) responded. 403 responders entered the withdrawal period; symptoms recurred in 83.9% (338 of 403) after a mean of 38 days. Of the 307 patients who subsequently entered retreatment 89.3% (274 of 307) responded. Among patients entering the retreatment period, 269 (87.6%) had responded within the first 4 weeks of initial treatment. Of these, 243 (90.3%) responded to tegaserod retreatment. Adverse events were infrequent and similar during 4 weeks of the initial treatment period (11.1%) and on retreatment (10.4%). The extension study, completed by 188 of 232 (81.0%) patients, demonstrated good long-term tolerability of tegaserod.

CONCLUSIONS

Irritable bowel syndrome with constipation patients can be successfully treated, and retreated, with tegaserod 6 mg b.d. Tegaserod was well-tolerated during initial and retreatment periods.

Options for patients with irritable bowel syndrome: contrasting traditional and novel serotonergic therapies

This article reviews the efficacy and tolerability of traditional therapies for irritable bowel syndrome (IBS) and concludes that they are limited by both poor efficacy and adverse effects. Serotonin, a neurotransmitter found mainly in the gut, appears to represent a link in IBS pathophysiological processes -- altered gut motility, abnormal intestinal secretion and visceral hypersensitivity. Recently, available treatments for IBS have targeted serotonin receptors that are involved in motor, sensory and secretory functions of the gut. Serotonergic agents, such as alosetron (a 5-HT3 receptor antagonist) and tegaserod (a selective 5-HT4 receptor partial agonist), provide global relief of the multiple symptoms of IBS with diarrhoea and IBS with constipation, respectively, and represent important additions to the IBS treatment armamentarium.

Influences of pelvic floor structures and sacral innervation on the response to distension of the cat rectum

The contributions to the rectal response to distension of the pelvic floor structures surrounding the rectum and of the sacral spinal innervation have never been studied. Using paralysed intercollicularly decerebrate, anaesthesia-free cats, we studied pressure-volume relationships during slow ramp distensions of the rectum. Results obtained from animals with intact pelvic cavities were compared with those following mobilization of the rectum from the pelvic floor musculature. To assess the influences of spinal outflow and afferent input, rectal pressure-volume relationships were measured in the mobilized rectum following bilateral sequential transection of the spinal roots S1 to S3, first dorsal, then ventral. Isolation of the rectum from the pelvic floor structures resulted in a decrease in balloon volume in the lower range of distension pressure but did not affect volumes at higher pressures. The only afferent effect was seen after sectioning of dorsal roots S1, which resulted in a decrease in balloon volume. The only efferent effect was seen after sectioning of ventral roots S3, which decreased balloon volume further. In conclusion, the rectal response to distension depends on the properties of the rectal wall. It may be influenced by somatic inputs, inputs from the myenteric nervous plexus, and from the parasympathetic and sympathetic nervous systems. Afferent inputs and spinal autonomic reflexes may decrease the tone of the rectal musculature during distension.

Serotonin type-4 receptors modulate the sensitivity of intramural mechanoreceptive afferents of the cat rectum

It has been suggested that serotonin (5-hydroxytryptamine) type-4 (5-HT4) receptors modulate the sensitivity of intrinsic afferents of the intestinal mucosa. We studied the involvement of 5-HT4receptors in the modulation of extrinsic afferent sensitivity of the intestinal wall. During distension ramps, mechanoreceptive rectal afferents in sacral dorsal roots were examined in decerebrate anaesthesia-free cats using the selective 5-HT4receptor partial agonist, tegaserod (HTF 919), and the 5-HT4receptor antagonist, SB 203186. The static discharge rate of the afferents evoked by rectal distension decreased after intravenous (i.v.) administration of tegaserod at intraluminal pressures above 30 mmHg, with the most effective reduction occurring at 50 mmHg. The effect was dose-dependent, with maximal reduction occurring at 1.2 mg kg-1 bodyweight, and could be partly reversed by i.v. administration of SB 203186. Tegaserod did not alter the pressure-volume relationship (compliance) of the rectum. It is tentatively concluded that 5-HT4receptor activation has an inhibitory effect on intramural mechanoreceptors in the cat's rectum. Our results are in line with the observation that tegaserod relieves the sensory symptoms of patients suffering from irritable bowel syndrome.

Tegaserod: a new 5-HT4 agonist

Tegaserod is a medication that has been shown to be of benefit in women with irritable bowel syndrome (IBS) associated with abdominal pain, bloating, and constipation. Tegaserod is a selective serotonin receptor subtype 4 partial agonist designed to interact with the network of cells and nerves throughout the gastrointestinal tract that use serotonin. Tegaserod has been shown to modulate both gastrointestinal motility and visceral sensitivity. Specifically, it increases the peristaltic reflex and decreases visceral sensitivity. Clinical studies have shown that tegaserod improves symptoms of abdominal pain, bloating, and constipation in women with IBS. This article discusses the role of serotonin in gastrointestinal tract physiology, the structure and pharmacokinetic profile of tegaserod, and clinical applications of this new drug.

The effect of low-dose erythromycin on whole gastrointestinal transit time of preterm infants

The aim of the study was to determine the effect of a low oral dose of erythromycin on whole gastrointestinal transit time [WGTT]. Erythromycin [EM] [1.5 mg/kg, 6 hourly] or placebo was given first over 7 days in a double blind randomized crossover study of 21 preterm infants with feed intolerance. Median [range] birth weight was 1420 [690, 2200] g and postconceptual age 32. 5 [20, 36.4] weeks. WGTT was assessed on day 3 of each treatment, by timing the transit of carmine red through the gut. Treatments were compared using Student's paired t test.

RESULTS

WGTT was significantly shorter following EM treatment as compared to placebo: mean [SD] 10.16 [4.6] h vs. 15. 9 [7.2] h, p<0.01.

CONCLUSION

Oral low-dose EM significantly shortens WGTT of feed-intolerant preterm infants.

Pressure-geometry relationship in the antroduodenal region in humans

Understanding of the control mechanisms underlying gastric motor function is still limited. The aim of the present study was to evaluate antral pressure-geometry relationships during gastric emptying slowed by intraduodenal nutrient infusion and enhanced by erythromycin. In seven healthy subjects, antral contractile activity was assessed by combined dynamic magnetic resonance imaging and antroduodenal high-resolution manometry. After intragastric administration of a 20% glucose solution (750 ml), gastric motility and emptying were recorded during intraduodenal nutrient infusion alone and, subsequently, combined with intravenous erythromycin. Before erythromycin, contraction waves were antegrade (propagation speed: 2.7 +/- 1.7 mm/s; lumen occlusion: 47 +/- 14%). Eighty-two percent (51/62) of contraction waves were detected manometrically. Fifty-four percent of contractile events (254/473) were associated with a detectable pressure event. Pressure and the degree of lumen occlusion were only weakly correlated (r(2) = 0.02; P = 0.026). After erythromycin, episodes of strong antroduodenal contractions were observed. In conclusion, antral contractions alone do not reliably predict gastric emptying. Erythromycin induces strong antroduodenal contractions not necessarily associated with fast emptying. Finally, manometry reliably detects ~80% of contraction waves, but conclusions from manometry regarding actual contractile activity must be made with care.

Randomised controlled study of oral erythromycin for treatment of gastrointestinal dysmotility in preterm infants

AIM

To evaluate the effectiveness of oral erythromycin as a prokinetic agent for the treatment of moderately severe gastrointestinal dysmotility in preterm very low birthweight infants.

METHODS

A prospective, double blind, randomised, placebo controlled study in a tertiary referral centre of a university teaching hospital was conducted on 56 preterm infants (< 1500 g) consecutively admitted to the neonatal unit. The infants were randomly allocated by minimisation to receive oral erythromycin (12.5 mg/kg, every six hours for 14 days) or an equivalent volume of placebo solution (normal saline) if they received less than half the total daily fluid intake or less than 75 ml/kg/day of milk feeds by the enteral route on day 14 of life. The times taken to establish half, three quarters, and full enteral feeding after the drug treatment were compared between the two groups. Potential adverse effects of oral erythromycin and complications associated with parenteral nutrition were assessed as secondary outcomes.

RESULTS

Twenty seven and 29 infants received oral erythromycin and placebo solution respectively. The times taken to establish half, three quarters, and full enteral feeding after the drug treatment were significantly shorter in the group receiving oral erythromycin than in those receiving the placebo (p < 0.05, p < 0.05 and p < 0.0001 respectively). There was also a trend suggesting that more infants with prolonged feed intolerance developed cholestatic jaundice in the placebo than in the oral erythromycin group (10 v 5 infants). None of the infants receiving oral erythromycin developed cardiac dysrhythmia, pyloric stenosis, or septicaemia caused by multiresistant organisms.

CONCLUSIONS

Oral erythromycin is effective in facilitating enteral feeding in preterm very low birthweight infants with moderately severe gastrointestinal dysmotility. Treated infants can achieve full enteral feeding 10 days earlier, and this may result in a substantial saving on hyperalimentation. However, until the safety of erythromycin has been confirmed in preterm infants, this treatment modality should remain experimental. Prophylactic or routine use of this medication for treatment of mild cases of gastrointestinal dysmotility is probably not warranted at this stage.

Nutrient-induced spatial patterning of human duodenal motor function

The spatiotemporal patterning of duodenal motor function has been evaluated comprehensively for the first time in humans, with a novel 21-lumen manometric assembly. In nine young, healthy volunteers (6 male, 3 female), duodenal motility was recorded during fasting and three 45-min intraduodenal (ID) nutrient infusion periods (Intralipid at 0.25, 0.5, and 1.5 kcal/min). Pressures were recorded along the length of the duodenum with an array of 18 sideholes at 1.5-cm intervals. Pressure patterns were compared for the final 20 min of each of the four periods. Compared with fasting, ID lipid was associated with regional variation in pressure wave (PW) sequences, with fewer proximally and more distally; this was not observed during fasting (P < 0.001). During fasting and all rates of lipid infusion, most (87-90%) PW sequences were short (1.5-4.5 cm), with a small number (2-4%) of 10.5 cm or longer. At all times, antegrade PW sequences occurred more frequently than retrograde sequences over all distances examined (3, 4.5, and >6 cm), and the proportion of antegrade sequences increased with greater PW sequence length (P = 0.0001). Increasing ID lipid rates appeared to produce dose-related suppression of PW sequences (P < 0.001). The frequency and spatial patterning of human duodenal motor function show substantial variability in response to different nutrient delivery rates. These complex patterns are likely to be involved in duodenal modulation of flow and gastric emptying rate.