Distal oesophageal motility characteristics in relation to amplitude of contraction in healthy persons

OBJECTIVES

We wanted to supply a new 'vertical' approach in the analysis of oesophageal contraction data by describing variables of oesophageal function in relation to the amplitude of contraction.

METHODS

Twenty-four-hour oesophageal manometry was performed in 20 healthy volunteers (11 women and 9 men; mean age, 47.5 years). Computer analysis was performed in pressure windows at 10, 15, 20, 30, 40, 50, 60, 70, and 80 mm Hg. Within each window two variables were extracted: the distribution (%) of peristaltic contractions and median duration (sec) of contractions.

RESULTS

The percentage of peristaltic contractions increased with increasing amplitude of contractions during the upright position (15-20 mm Hg window: mean (+/- SD) 68.2% (+/- 13.3%), versus 70-80 mm Hg window: 85.0% (+/- 13.0%) (P < 0.001)) and meal periods (66.9% (+/- 13.8%) versus 92.2% (+/- 11.2%) (P < 0.001)) but not in the supine position (75.9% (+/- 14.6%) versus 73.5% (+/- 16.1%) (P = 0.64)). Contraction duration diminished with increasing contraction amplitude (upright, 15-20 mm Hg window: 3.2 sec (+/- 1.5 sec) versus 70-80 mm Hg window: 1.5 sec (+/- 1.0 sec) ( P < 0.0001); meal: 3.8 sec (+/- 1.7 sec) versus 1.9 sec (+/- 1.1 sec) (P < 0.01); supine: 4.1 sec (+/- 3.0 sec) versus 2.2 (+/- 1.5 sec) (P = 0.03)). The percentage of peristaltic contraction was lower during the supine periods than during meals and upright periods at high amplitudes (70-80 mm Hg window; P < 0.05). The number of contractions decreased linearly on a logarithmic scale with pressure window amplitude.

CONCLUSIONS

Pressure wave amplitude and organization were closely related. Accurate base-line determination and delineation are critical for the interpretation of oesophageal manometric recordings.

Effects of two oral erythromycin ethylsuccinate formulations on the motility of the small intestine in human beings

Fourteen-membered macrolides are known to produce alterations in digestive tract motor activity; these include the induction of strong gastric contractions and a decrease in the motility of the small intestine. The aim of the study was to compare the effects of two different formulations of erythromycin ethylsuccinate (EE) on duodenojejunal motility. Compared with the more commonly used crystalline formulation of EE (CEE), the amorphous formulation (AEE) has previously been described to have greater bioavailability and to induce significantly fewer gastrointestinal side effects when given at therapeutic and what have been considered to be equivalent oral doses (i.e., CEE, 1,000 mg every 12 h; AEE, 500 mg every 12 h). In a crossover double-blind study, duodenojejunal manometric recordings were performed for 10 volunteers treated with placebo, CEE at 1,000 mg, or AEE at 500 mg. Recordings for each volunteer were obtained for a fed period after a standard dinner and then for a nocturnal fasting period. When compared with the placebo, CEE significantly decreased the motility index of the duodenum during the 30 min after the peak serum erythromycin concentrations, shortened the duration of the fed state, and had no effect during the fasting state. In contrast, AEE did not significantly modify any motility parameter. Because AEE produced significantly lower concentrations in serum than CEE, these results do not necessarily imply that the two formulations of EE act differently on the motility of the small intestine.

Vagus-dependent and vagus-independent mechanisms of action of the erythromycin derivative EM574 and motilin in dogs

The motor-stimulating action of de(N-methyl)-N-isopropyl-8,9-anhydroerythromycin A 6,9-hemiacetal (EM574) on the upper gastrointestinal tract was studied in fasted conscious dogs using chronically implanted force transducers and compared with those of porcine motilin and cisapride. EM574 induced gastric phase III-like migrating contractions and increased the plasma motilin levels slightly. The gastric motility induced by low doses of EM574 and motilin was abolished by a 5HT3-receptor antagonist ondansetron and acute vagal blockade, whereas under these conditions, high doses of both agents induced contractions, which were abolished by atropine. Cisapride-induced gastric motility was inhibited by atropine and acute vagal blockade, but not by ondansetron. EM574 did not stimulate gastric secretion in the basal state. These results indicate that EM574- and motilin-induced gastrointestinal motility is attributable mainly to motor-stimulating vagal cholinergic neurons, and 5HT3-receptors are probably involved in the process. At high doses, EM574 and motilin also appear to stimulate cholinergic neurons in a non-vagal pathway, probably the enteric nervous system.

Antral axial forces postprandially and after erythromycin in organic and functional dysmotilities

Our aims were to measure antral axial forces in patients with suspected upper gut dysmotilities and to compare the number of antral contractions detected by an axial force catheter and by manometric sensors in the distal antrum and pylorus. Fifteen patients (2 men, 13 women; mean age 42 years) underwent studies for 3 hr fasting, 2 hr postprandially, and up to 60 min after intravenous erythromycin (3mg/kg). Seven patients had gastroparesis or chronic intestinal pseudoobstruction, five functional disease, and three subacute obstruction. Postprandially, the number of peaks detected by the two methods was not significantly different; however, after erythromycin, the axial catheter detected more contractions (P = 0.02). Erythromycin significantly increased the number of postprandial axial forces (from 1.2 +/- 0.3/min to 2.5 +/- 0.3/min, P < or = 0.01) in the whole group and in the organic dysmotility group (P = 0.01). Erythromycin significantly increases the number of axial forces in functional and organic upper gut dysmotilities, but the axial force catheter is not advantageous over manometry for postprandial measurements of antral motility.

Erythromycin stimulates gastric emptying after esophagectomy with gastric replacement: a randomized clinical trial

Delayed gastric emptying after esophagogastrectomy can pose a significant early postoperative problem. Because erythromycin, which stimulates the gastric antral and duodenal motilin receptor, has been shown to significantly increase gastric emptying in patients with diabetic gastroparesis, we decided to evaluate its effect on gastric emptying after esophagogastrectomy.

METHODS

Twenty-four patients (18 men and six women, age range 41 to 79 years, median 66 years) were randomized to receive either erythromycin lactobionate (200 mg in 50 ml normal saline solution intravenously) (n = 13) or placebo (50 ml normal saline solution intravenously (n = 11) 11 days after esophagogastrectomy (with pyloric drainage procedure). After erythromycin or placebo had been infused over a 15-minute period, patients ingested a solid meal (scrambled egg with bread) labeled with technetium 99m sulfur colloid (500 microCi) over approximately 15 minutes. Dynamic images of the stomach were then acquired over 90 minutes in the supine position by gamma imaging. Results were expressed as percentage of counts retained in the stomach (percent gastric retention) over time.

RESULTS

There were no side effects of erythromycin. In the placebo group, the mean percent of radiolabeled meal retained in the stomach after 90 minutes was 88%, which was significantly greater than in the erythromycin group, 37% (p < 0.001). In addition, analysis of covariance demonstrated that the rate of gastric emptying (slope of the line) was significantly greater in the erythromycin-treated group than in the placebo group (p < 0.0001).

CONCLUSION

Early satiety after esophagogastrectomy may be due to delayed gastric emptying and not due to a decrease in the gastric reservoir. Intravenous erythromycin significantly improves gastric emptying in patients after esophagogastrectomy by stimulating gastric motility.

The effect of intravenous erythromycin on esophageal motility in healthy subjects

BACKGROUND

It has been confirmed that erythromycin has gastrokinetic properties of enhancing gastric emptying both in health and disease. The objective of the present study was to investigate any possible effect of erythromycin on esophageal motility.

METHODS

In 14 healthy subjects, standard esophageal manometry was performed before and after the intravenous administration of 200 mg of erythromycin. The calculated manometric parameters of esophageal motility were the lower esophageal sphincter (LES) pressure; the amplitude and duration of peristalsis at 5, 10, and 15 cm proximal to the LES; and the velocity and strength of peristalsis at 5 cm proximal to the LES.

RESULTS

Erythromycin significantly increased the LES pressure (P<0.001), and the amplitude (P=0.002), duration (P=0.003), strength (P=0.014) and velocity (P=0.008) of peristalsis at 5 cm proximal to LES. Erythromycin also increased the amplitude of peristalsis at 10 cm proximal to the LES (P=0.035).

CONCLUSION

Erythromycin affects the motility of the distal esophagus.

Increase of swallows before onset of phase III of migrating motor complex in normal human subjects

The aim of our study was to analyze the relation between the deglutitive activity and fasting esophageal and gastric motility in normal subjects. Fifteen healthy subjects (9 males, 6 females) with a mean age of 42 years (range 19-65) were studied. A 24-hr pH-manometric recording was performed using a probe with four solid-state recording sites 10 cm apart, placed so as to record the motor activity of esophageal body, lower esophageal sphincter (LES) or distal part of the esophagus, and gastric antrum. An additional probe with one recording site was placed in the pharynx to evaluate swallowing. A pH electrode was also placed at 5 cm above the sphincter. Data were transferred to a personal computer and analyzed using specific software. Subjects received two meals during the recording session. MMCs were almost exclusively recorded during the nighttime. A mean of 2 +/- 0.94 (SD) MMC per subject was detected with a mean (+/- SD) interval, between each cycle, of 86.11 +/- 34.53 min. During the 30 min preceding gastric phase III, the number of swallows showed an increase that reached statistical significance 5 min before the onset of phase III. A similar pattern was observed for the area under the curve (AUC) of the esophagus and LES. In conclusion deglutition and esophageal motility vary with the MMC, suggesting that the deglutitive activity is part of the interdigestive motility pattern.

Therapeutic strategies for motility disorders. Medications, nutrition, biofeedback, and hypnotherapy

Gastrointestinal motility is regulated by a complex balance of inhibitory and excitatory neuronal, humoral, and mechanical factors. The goal in the management of motility disorders is to maintain adequate nutrition while decreasing symptoms. This can be accomplished by medications and support of nutrition and biofeedback; the application of these therapeutic strategies to patients with gut motility disorders is reviewed.

Ambulatory esophageal manometry/pH-metry discriminates between patients with different esophageal symptoms

Ambulatory esophageal manometry/pH-metry has been used primarily in patients with chest pain of presumed esophageal origin, and it is unclear whether the discriminating power of this test applies to other esophageal symptoms. In the present study, prolonged ambulatory manometry/pH recordings were compared in 17 healthy controls, 12 patients with atypical chest pain, and 11 patients with chest pain and nonstructural dysphagia using the Synectics microdigitrapper system. Chest pain patients tended to have higher values for all the pH variables, but their esophageal motility parameters were no different than controls. On the other hand, the chest pain plus dysphagia group was characterized by a significantly lower proportion of propagated contractions between 10 and 5 cm above the lower esophageal sphincter. This group also tended to have a higher frequency of high-amplitude or prolonged-duration contractions. In comparison to the results of standard stationary esophageal manometry, the prolonged ambulatory recordings were more sensitive in detecting esophageal motor dysfunction in the two patient groups. This study suggests that quantitative analysis of ambulatory pH/motility recordings is a sensitive method of evaluating patients with suspected esophageal dysfunction.

Pathological esophageal acidification and pneumatic dilitation in achalasic patients. Too much or not enough?

Endoscopy, esophageal manometry and pH monitoring, gastric emptying test, and heartburn quantification on a visual analog scale were performed in 22 achalasic patients in order to clarify which events are associated with pathological esophageal acidification after successful LES dilatation. Five patients presented pathological acidification. Dilatation reduced LES tone from 38.3 +/- 4.2 to 14.6 +/- 1.1 mm Hg (mean +/- SEM); there was, however, no difference between nonrefluxers and refluxers (14.8 +/- 1.2 vs 13.8 +/- 2.5 mm Hg). The emptying time in achalasic patients was delayed compared to controls (315.9 +/- 20.9 min vs 209 +/- 10.4) due to prolonged lag-phase and reduced slope of the antral section-time curve, but, again, there was no difference between refluxers and nonrefluxers. The acid clearance was delayed in refluxers compared to nonrefluxers (15.9 +/- 4.5 vs 2.5 +/- 1.8 min, P<0.05). Two refluxers presented grade 1 esophagitis; one of them developed an esophageal ulcer. The heartburn score was the same in refluxers and nonrefluxers. Pathological acidification after pneumatic dilatation is associated with persistent problems in esophageal emptying rather than with excessive sphincter divulsion.

Drugs coordinating and restoring gastrointestinal motility and their effect on selected hypodynamic gastrointestinal disorders in horses and cattle

Hypodynamic gastrointestinal disorders in horses and cattle that are thought to benefit from treatment with drugs restoring and coordinating gastrointestinal motility include postoperative ileus and large colon impaction in the horse and displacement of the abomasum and dilatation of the cecum in cattle. Important physiologic, pathophysiologic and pharmacologic mechanisms involved in the intrinsic control of gastrointestinal motility include cholinergic, adrenergic, dopaminergic, serotoninergic, and opioid-mediated pathways. Preliminary results suggest that cisapride, acting on 5-Hydroxytryptamine receptors, might be useful for treatment of idiopathic postoperative ileus and the alpha 2-adrenoceptor blocking agent yohimbine for endotoxic postoperative ileus. Naloxone, an opioid antagonist, and neostigmine, an acetylcholinesterase inhibitor, are thought to restore motility of the large colon in cases of large colon impaction in the horse. Bethanechol and neostigmine significantly increase myoelectric activity of the cecum and proximal loop of the ascending colon in healthy cows. Investigations of the effects of prokinetic drugs on displacement of the abomasum of cattle do not allow any conclusions because no results derived from controlled experimental disease models are available.

Stimulatory mechanism of EM523-induced contractions in postprandial stomach of conscious dogs

BACKGROUND & AIMS

EM523, a motilin agonist, is intended to be used as a gastroprokinetic during the postprandial period, but the mechanism(s) by which EM523 stimulates postprandial contractions in the stomach has not been studied before. The aim of this study was to examine the mechanism of contraction-stimulating activity by EM523 in fed dogs.

METHODS

Contractile activity in the gastric antrum of 5 dogs was monitored using a long-term implanted force transducer and measured by integrating the area under the curve. Test materials were continuously infused or injected intravenously.

RESULTS

EM523 (1-30 micrograms/kg) induced a dose-dependent increase in fed-type contractions. EM523-induced contractile activity was partially inhibited by atropine, hexamethonium, dopamine, 5-hydroxytryptamine 3 (5-HT3) receptor antagonist, and substance P antagonist. Atropine-resistant and EM523-induced contractions were further inhibited by 5-HT3 receptor antagonist and substance P antagonist, and the combined use of the two antagonists completely eliminated the atropine-resistant and EM523-induced contractions.

CONCLUSIONS

EM523-induced contractions in the fed stomach are quite different from phase III contractions in the fasted state and are mediated partially through the cholinergic pathway. The noncholinergic pathway involves 5-HT3 and neurokinin 1 receptors.

Effect of octreotide and erythromycin on idiopathic and scleroderma-associated intestinal pseudoobstruction

Treatment of chronic intestinal pseudoobstruction with prokinetic agents has been disappointing. Our study was designed to determine if octreotide and erythromycin would provide sustained relief from nausea, abdominal pain, and bloating in pseudoobstruction. Using gastrointestinal manometry, quantitative parameters of the activity front of the migrating motor complex at baseline and after prokinetic therapy with erythromycin and octreotide were determined in 14 patients with intestinal pseudoobstruction who had nausea, abdominal pain, and bloating. Patients were treated with erythromycin and octreotide for 20-33 weeks. Octreotide increased the frequency, duration, and motility index of activity fronts (AFs) from 1.2 +/- 0.3 AFs/4 hr, 2.7 +/- 0.7 min, and 85 +/- 23 min mm Hg to 4.1 +/- 0.8 AFs/4 hr, 5.5 +/- 0.7 min, and 152 +/- 24 min mm Hg, respectively (P < 0.05). Antral activity was decreased from 63 +/- 14 to 23 +/- 8% by octreotide (P < 0.05). Erythromycin induced antral activity; however, small intestinal motor activity was suppressed. While on erythromycin and octreotide, five patients had long-term improvement of nausea and abdominal pain. All responders had at least 5 AFs/4 hr induced by octreotide. We conclude that octreotide and erythromycin relieve abdominal pain and nausea in pseudoobstruction. Patients who have at least 5 AFs/4 hr after octreotide administration are most likely to clinically respond.

Automatic detection of esophageal pressure events. Is there an alternative to rule-based criteria?

Ambulatory long-term motility recording is used increasingly for evaluation of esophageal function. The enormous amount of motility data recorded by this method demands subsequent computer analysis. One of the most crucial steps of this analysis becomes the process of automatic selection of relevant pressure peaks at the various recording levels. Until now, this selection has been performed entirely by rule-based systems, requiring each pressure deflection to fit within predefined rigid numerical limits in order to be detected. However, due to great variations in the shapes of the pressure curves generated by muscular contractions, rule-based criteria do not always select the pressure events most relevant for further analysis. We have therefore been searching for a new concept for automatic event recognition. The present study describes a new system, based on the method of neurocomputing. A large sample of normal esophageal pressure deflections was used as a "learning set," and the performance of the trained neural networks was subsequently verified on different sets of data from normal subjects. Our trained networks detected pressure deflections with sensitivities of 0.79-0.99 and accuracies of 0.89-0.98, depending on the recording level within the esophageal lumen. The neural networks often recognized peaks that clearly represented true contractions but that had been rejected by a rule-based system. We conclude that neural networks have potentials for automatic detections of esophageal, and possibly also other kinds of gastrointestinal, pressure variations.

Effect of erythromycin on gastric motility in mechanically ventilated critically ill patients: a double-blind, randomized, placebo-controlled study

OBJECTIVE

To document the action of erythromycin on gastric emptying and motility in mechanically ventilated patients.

DESIGN

Crossover, double-blind, randomized, placebo-controlled study.

SETTING

General intensive care unit in a university hospital.

PATIENTS

Ten patients, mechanically ventilated, in a stable hemodynamic condition.

INTERVENTIONS

Erythromycin (200 mg i.v. over 30 mins) and placebo were infused at mid-morning, on two consecutive days, in a random order. Pressure changes in the gastric antrum were recorded by means of a multi-lumen manometric tube (perfused catheter technique) over a period of 300 mins, beginning with the institution of the erythromycin or placebo infusion. Gastric emptying was simultaneously assessed by the kinetics of the absorption of acetaminophen delivered into the stomach (1 g with 20 mL of water) immediately before the infusion.

MEASUREMENTS AND MAIN RESULTS

Motility was quantified by determining the number of contractions, the amplitude of contractions, and the Motility Index (Motility Index = natural logarithm [sum of amplitude x number of contractions] + 1). Comparison between placebo and erythromycin was made for the first hour after the infusion and for the whole recording session. The maximal acetaminophen concentration, the time to reach the peak acetaminophen concentration, and the area under the concentration-time curve at 60 mins were obtained from serial determinations of plasma acetaminophen concentrations. Compared with placebo, the mean number of contractions (104 +/- 34 vs. 5 +/- 8; p = .003), the mean amplitude of contractions (52 +/- 16 vs. 20 +/- 17 mm Hg; p = .005), and the Motility Index (13.06 +/- 0.95 vs. 4.45 +/- 3.54; p = .004) were significantly increased during the first hour after erythromycin infusion compared with placebo. Number of contractions (p = .017) and Motility Index (p < .001) after erythromycin infusion remained significantly higher when values throughout the whole recording session were considered. The following data were noted after erythromycin was infused: a) the time to reach the peak acetaminophen concentration was shorter (32 +/- 8 vs. 171 +/- 93 mins; p = .007); b) the maximal acetaminophen concentration was higher (22.09 +/- 6.23 vs. 5.38 +/- 3.80 micrograms/mL; p = .007); and c) the area under the concentration-time curve at 60 mins increased markedly (730 +/- 269 vs. 72 +/- 42 micrograms/min/mL; p = .002) as compared with placebo.

CONCLUSION

In mechanically ventilated patients, intravenous erythromycin (200 mg over 30 mins) increases indices of antral motility and accelerates gastric emptying as assessed by the kinetics of acetaminophen absorption.

Erythromycin enhances fasting and postprandial proximal gastric tone in humans

BACKGROUND & AIMS

Low doses of erythromycin induce antral contractions and accelerate gastric emptying. However, the effect of erythromycin on the proximal stomach remains unknown. The aim of this study was to assess the effect and mechanism(s) of action of erythromycin on proximal gastric tone in humans.

METHODS

Gastric tone was measured using an electronic barostat in two groups of 6 subjects both in the fasting state and after a 200-kcal meal. On different occasions, subjects received saline, atropine alone (6 micrograms.kg-1.h-1 for 30 minutes), erythromycin alone (1.5 mg/kg in the fasting state and 1.5 and 3.0 mg/kg in the postprandial state), and erythromycin plus atropine.

RESULTS

Low-dose (1.5 mg/kg) erythromycin enhanced fasting gastric tone, but only the 3.0-mg/kg dose reduced the duration of meal-induced relaxation (37 +/- 14 vs. 105 +/- 20 minutes; P < 0.01). Atropine did not change the fasting or postprandial gastric tone as well as the erythromycin-induced responses. Plasma motilin levels were unaffected by erythromycin infusion. No correlation was observed between gastric tone and plasma motilin or erythromycin levels.

CONCLUSIONS

Erythromycin enhances fasting and postprandial proximal gastric tone in humans by a mechanism that does not seem to involve endogenous motilin release or a cholinergic pathway.

From motilin to motilides: a new direction in gastrointestinal endocrinology

Investigation into gastrointestinal irritation from the use of erythromycin lead to the discovery of the gastrointestinal motor effect of this antibiotic. Erythromycin and gastrointestinal peptide motilin share many similar gastrokinetic activities, and studies indicate that erythromycin mimics the effect of motilin through motilin receptor agonism. Since erythromycin is readily available for clinical use, it may offer an alternative therapeutic approach to gastroparesis and related conditions. Several analogs of erythromycin without antimicrobial activity are also shown to possess similar motor effects, thus termed "motilides". A growing number of motilides may expand our knowledge on gastrointestinal peptides.

Neonatal-onset chronic intestinal pseudo-obstruction syndrome

Between January 1985 and January 1990, six cases of neonatal-onset chronic intestinal pseudo-obstruction syndrome (CIPS) were identified. Failure to gain weight in six cases, abdominal distention in five, and vomiting in five were the most common presenting symptoms. The contrast studies of the gastrointestinal tract demonstrated delayed transit time in 6/6, jejunal or ileal dilatation in 1/6, megaduodenum in 1/6, dilatation of the colon with barium retention in 4/6, and microcolon in 1/6. Urinary tract involvement was noted in three patients. Laparotomy, performed in three patients, revealed no mechanical obstruction. Except for hypoganglionosis in Patient 4, no recognizable neuropathy or myopathy was noted histopathologically. Four patients expired within 2 months after discharge. We conclude that CIPS with neonatal onset should be suspected when infants have urinary retention and abdominal distention or constipation beginning at birth or soon after. The prognosis of CIPS presenting in the newborn period appears worse than that presenting in childhood or adulthood.

Effect of cisapride on myoelectrical and motor responses of antropyloroduodenal region during intraduodenal lipid and antral tachygastria in conscious dog

The myoelectrical and motor response of the antropyloroduodenal region to intraduodenal nutrient stimulation or antral tachygastria represent useful models for, respectively, physiological and pathophysiological gastric stasis to test the efficacy of prokinetic drugs. We evaluated the effects of an intravenous bolus of cisapride (0.63 mg/kg) on the myoelectrical and motor response of the antropyloroduodenal region to an intraduodenal triglyceride emulsion (10% Intralipid, 0.5 ml/min) or antral tachygastria in conscious dogs. Intraduodenal lipid suppressed antral motility (P < 0.05, compared to intraduodenal saline) and stimulated phasic pyloric contractions (P < 0.01, compared to intraduodenal saline), a motor pattern known to be associated with delayed gastric emptying. During intraduodenal lipid stimulation cisapride virtually abolished all isolated pyloric motor events (P < 0.05) and stimulated antral and duodenal motility (P < 0.05 for both) and antropyloroduodenal coordination (65% versus 15%; P < 0.05). Antral tachygastria was associated with a higher number of isolated pyloric motor events in the fasted state [0.8 (0.7-1.1) per minute versus 0.2 (0-0.3) per minute; P < 0.05], but not during intraduodenal lipid stimulation [1.1 (0.9-1.7) per minute versus 1.2 (1.0-1.9) per minute; NS]. Cisapride decreased the number and duration of spontaneous episodes of antral tachygastria during intraduodenal saline and lipid infusion (P < 0.05 for both) and abolished the tachygastria-associated motor patterns. Cisapride induced a 20% decrease in the antral slow-wave frequency during intraduodenal saline and lipid, irrespective of gastric pacemaker rhythm. We conclude that: (1) cisapride overcomes feedback from small intestinal lipid receptors on myoelectrical and motor activities of the antropyloroduodenal region and decreases antral slow-wave frequency, and (2) cisapride inhibits antral tachygastria and tachygastria-associated motor patterns. These effects may contribute to the effective gastrokinetic properties of cisapride in physiological and certain forms of pathophysiological gastric stasis.

Gastric but not duodenal motor effects of oral erythromycin are dose related

There has been increasing interest in the potential use of erythromycin as a prokinetic agent, despite limited data on the effect of oral administration on gastrointestinal motility. We have now evaluated, in 15 conscious pigs fitted with strain gauges, the response of (i) basal gastric motility and (ii) gastric motility during inhibition with intraduodenal triglycerides infusion to increasing doses of oral erythromycin. In the basal state, erythromycin led to dose-dependent increases in both the amplitude (10-30 mg kg-1) and the frequency (10-55 mg kg-1) of gastric contractions. The corpus was more responsive than the antrum, with an increase in amplitude at lower doses. The amplitude of the duodenal contractions was also improved but not in a dose-dependent manner. Gastroduodenal coordination was unchanged regardless of the dose of erythromycin. Following inhibition of gastric motility, a dose of erythromycin below 45 mg kg-1 increased both the amplitude of gastric contractions and the gastroduodenal coordination, although individual doses produced smaller increases in amplitude than in the basal state. These results suggest that erythromycin has a different mechanism of action in the stomach compared with the duodenum. The reduced effectiveness of large doses of erythromycin has important therapeutic implications.

Impaired gastric relaxation in patients with achalasia

Achalasia is considered a primary motility disorder confined to the oesophagus. The lower oesophageal sphincter (LOS) in achalasia is frequently hypertonic and manifests absent or incomplete relaxation in response to deglution. On the other hand, the LOS and the proximal stomach act physiologically as a functional unit whereby relaxation of the LOS during deglution is associated with receptive relaxation of the proximal stomach. Thus, this study investigated the hypothesis that impaired LOS relaxation in patients with achalasia might be associated with impaired relaxation of the proximal stomach. The study consisted of 20 patients with achalasia and 10 healthy controls. Gastric tone variations were quantified using an electronic barostat. Firstly, the study established the basal gastric tone (intragastric volume at the minimal distending pressure+1 mm Hg) and gastric compliance (volume/pressure relation) during isobaric distension (increasing stepwise the intragastric pressure from 0 to 20 mm Hg up to 600 ml). Secondly, the gastric tone response to cold stress (hand immersion into ice water for five minutes) or to control stimuli (water at 37 degrees) was determined. Basal gastric tone mean (SEM) was similar in achalasia and in healthy controls (125 (9) ml v 138 (9) ml, respectively). Compliance was linear and similar in both groups, which also showed similar gastric extension ratios (58 (7) ml/mm Hg v 57 (6) ml/mm Hg). Cold stress induced a gastric relaxatory response that, as a group, was significantly lower in achalasia than in healthy controls (volume: 43 (20) ml v 141 (42) ml; p < 0.05). The responses in each group were not uniform, five of the 20 patients with achalasia showed definite (volume > 100 ml) relaxatory responses whereas four of the 10 healthy controls did not. In conclusion, reflex gastric relaxation is impaired in most patients with achalasia showing that the proximal stomach, and not exclusively the oesophagus, may be effected by the disease.

Autonomic dysfunction in patients with achalasia

It has been previously shown that patients with achalasia may have motor abnormalities of the stomach, small bowel and biliary system. This study investigates whether a disturbance of extraintestinal autonomic function occurs. Autonomic function studies were performed in 15 patients with achalasia and 15 age- and sex-matched healthy controls. Pupillograms were obtained during darkness, light exposure and after pilocarpine administration. Cardiovascular function studies included determinations of heart rate variation during deep breathing and orthostasis. In addition, we determined blood pressure changes in response to sustained handgrip, cold exposure and orthostasis. Neurohormonal function was investigated by measuring serum pancreatic polypeptide (PP) levels prior to and following sham feeding. Pupillary function did not differ in patients as compared with controls. However, 9 of 15 patients (95% CI: 32-84%) and none of the controls showed at least one abnormal autonomic cardiovascular response. A significant difference between the two groups was observed in sympathetic function (P = 0.023). More patients than controls did not respond to sham feeding with a PP increase. It is concluded that some patients with achalasia exhibit an abnormality of the autonomic nervous system that extends beyond the gastrointestinal tract. These abnormalities mainly concern cardiovascular function but may also involve neurohormonal responses.

Comparison between physiologic and erythromycin-induced interdigestive motility

BACKGROUND

The last part of duodenal phase III of the migrating motor complex behaves as a retroperistaltic pump. We have compared the phase-III-like gastroduodenojejunal activity induced by erythromycin with the naturally occurring phase III, focusing on peristaltic patterns. The effect of two doses of erythromycin, 3 mg/kg/h and 12 mg/kg/h (in four subjects), or saline, given intravenously for 15 min, was studied in nine fasting healthy subjects (five men and four women).

METHODS

Motility was recorded on three different days. On one day standard 5-h eight-channel antroduodenojejunal manometry was performed and saline infused 30 min after the first phase III. On the other two study days, erythromycin in the low or the high dose was infused and recording performed for another 2-h period.

RESULTS

The low dose of erythromycin induced a phase III in the stomach in all subjects within 12.8 +/- 1.4 min. In contrast, the higher dose did not induce phase-III activity within the 1st h after infusion but induced marked antral pressure waves. The duration of the erythromycin-induced phase III and the naturally occurring antral phase III was 4.7 +/- 1.7 and 1.9 +/- 0.3 min, respectively (p < 0.01). The duration of the erythromycin-induced phase III in the proximal jejunum was 44% shorter than the spontaneous one (p < 0.01). The propagation velocity, from the proximal duodenum to the proximal jejunum, of the erythromycin-induced phase III was slower than that of the spontaneous phase III: 5.7 +/- 0.9 and 15.9 +/- 3.9 cm/min, respectively (p < 0.01). In the proximal duodenum the proportion of retrograde pressure waves (of all propagating waves) was about 10% in early phase III, increasing to about 85% in late phase III in both the spontaneous and erythromycin-induced phase III. In the proximal jejunum retrograde pressure waves were not observed in phase III.

CONCLUSIONS

Erythromycin given in a low dose is very effective in inducing phase-III-like motility. The last part of duodenal phase III is characterized by retroperistalsis also when this motility phase is induced by erythromycin.

Gastric motility following oesophagectomy

The motility of the vagally denervated transposed stomach after oesophagectomy was examined by ambulatory gastric manometry and videofluoroscopy. Two groups of subjects were studied. Group 1 comprised ten patients who had undergone oesophagectomy 6-12 months previously and group 2 consisted of six normal control subjects. Studies were performed on fasting and fed subjects, and following injection of erythromycin 8 mg/kg. No distinguishable manometric wave activity was seen in either group while fasting. Feeding generated a measurable wave pattern in the patient group only. A significant increase in the mean (s.e.m.) distal wave amplitude was identified after infusion of erythromycin in both patients (34.0(15.1) versus 12.2(3.1) mmHg, P < 0.05) and controls (15.1(3.4) versus 5.0(0.0) mmHg, P = 0.05). The response to erythromycin was more rapid in patients than in controls (mean(s.e.m.) 113(16) versus 377(133) s, P < 0.05) and the effect persisted for longer (more than 1 h) in those who had undergone oesophagectomy. Videofluoroscopy confirmed purposeful motility in both the normal and vagally denervated stomach. It is concluded that the transposed stomach is a dynamic conduit. Enhancement of motility was greatest in the denervated stomach, indicative of denervation supersensitivity.

Hyperinsulinaemia impairs gastrointestinal motility and slows carbohydrate absorption

Experimental euglycaemic hyperinsulinaemia (insulin levels 46 +/- 4 mU/l) impaired the post-absorptive gastrointestinal motility in healthy individuals; the effect being particularly pronounced in the upper gastrointestinal tract (stomach and proximal duodenum). The postprandial gastric emptying, measured with a standardized 99mTc labelled meal, was also significantly delayed (t50 increased by 38% or 32 min). This was combined with a slower carbohydrate absorption (delay in peak blood glucose level about 40 min). Furthermore, during experimental hyperinsulinaemia higher blood glucose levels were seen at 120 min than at 60 min after food ingestion. This was not seen in any subject in the control study where only 0.9% NaCl was infused. Blood levels of the motility-stimulating hormone, motilin, were significantly lower during experimental hyperinsulinaemia. Thus, experimental hyperinsulinaemia impairs the gastrointestinal motility in both the postabsorptive and postprandial states. This effect is combined with a delayed carbohydrate absorption. Hyperinsulinaemia per se may thus lead to alterations in carbohydrate absorption and can also contribute to the gastrointestinal disturbances in diabetes.

Macrolides in roles beyond antibiotic therapy

Erythromycin and other macrolides with a closely related structure are widely used antibiotics. Side-effects related to administration of such drugs are mostly gastrointestinal. The direct effect of erythromycin on gastrointestinal motility was studied; it was found to have a stimulatory effect proximally, on stomach and duodenal motility, with an apparent distal inhibition. Gastric emptying was accelerated by erythromycin via an antroduodenal coordination mechanism, an effect that has proved to be beneficial in surgical and medical conditions in which gastroparesis is a problem. Erythromycin is now used experimentally and clinically; it has been found to accelerate gastric as well as gallbladder emptying and to have an effect on the oesophagus. Analogues of erythromycin have been developed that have potent gastrointestinal activity but little or no antibacterial potential. Macrolides modulate the antibacterial action of neutrophils, with some action on the oxidative burst. Finally, two new macrolide immunosuppressants have been developed that compare favourably with traditional drugs.

Effect of erythromycin administration on upper gastrointestinal motility in scleroderma patients

BACKGROUND

Gastrointestinal involvement is frequent in patients with scleroderma. Erythromycin, a macrolide antibiotic, has been shown to accelerate gastric emptying in normal subjects and diabetic patients. The present study investigated the effects of acute erythromycin administration on gastric and gallbladder motility in patients with scleroderma and gastrointestinal involvement.

METHODS

Twelve scleroderma patients and 14 healthy subjects were investigated. Each subject was investigated on 4 different days. Gastric and gallbladder emptying and gastric motility were determined by sonography and manometry, and the effect of 2 mg/kg/h erythromycin in fasted patients or after semisolid meal evaluated.

RESULTS

The half-time of gastric emptying in response to semisolid meal was 121.3 +/- 14.0 min (SE) in scleroderma patients and 45.7 +/- 10.4 min in healthy subjects (P < 0.01). The peak of gallbladder emptying occurred later in scleroderma patients (95.0 +/- 5.0 min) than in healthy subjects (45.0 +/- 8.0 min) (P < 0.01). Erythromycin stimulated gastric and gallbladder motility in fasted subjects, as shown by manometry and sonography, and accelerated gastric and gallbladder emptying when administered immediately before the meal (P < 0.01).

CONCLUSIONS

Erythromycin accelerates gastric and gallbladder emptying in scleroderma patients and might be helpful in the treatment of gastrointestinal motor abnormalities in these patients.

Effect of erythromycin on antroduodenal motility in children with chronic functional gastrointestinal symptoms

To evaluate the effects of erythromycin on antroduodenal motility in children with chronic functional gastrointestinal symptoms, we studied 35 consecutive subjects referred for diagnostic motility studies. We recorded fasting motility for > 4 hr, then infused in random order either 1 or 3 mg/kg erythromycin intravenously over 1 hr and continued the study for another hour. Erythromycin induced phase III in 18 of 20 children who had phase III during fasting compared to only one of 15 who did not (P < 0.001). The antral motility index increased after erythromycin (1596 +/- 323 vs 436 +/- 242 mm Hg/30 min before erythromycin, P < 0.005) but the duodenal motility index did not change. The antral motility index was greater in children receiving 3 mg/kg than in those receiving 1 mg/kg (1968 +/- 391 vs 1226 +/- 285 mm Hg/30 min, P < 0.01), but duodenal motility indices did not differ. Only one child receiving the lower dose erythromycin complained of abdominal pain, nausea, or vomiting vs 9 of 19 the children receiving the higher dose (P < 0.02). In summary, in children with chronic functional gastrointestinal disorders, erythromycin rarely induced phase III in patients who did not have it during fasting. When different doses erythromycin are compared, 1 and 3 mg/kg are equally efficacious in inducing phase III episodes; the lower dose is associated with fewer side effects and the higher dose produces a higher antral motility index.

Disordered gastric motor function in diabetes mellitus

The application of novel investigative techniques has demonstrated that disordered gastric motility occurs frequently in diabetes mellitus. Gastric emptying is abnormal in about 50% of diabetic patients and delay in gastric emptying of nutrient-containing meals is more common than rapid emptying. The blood glucose concentration influences gastric motility in diabetes. In IDDM patients, gastric emptying is retarded during hyperglycaemia and may be accelerated by hypoglycaemia. Gastroparesis therefore does not necessarily reflect irreversible autonomic neuropathy and blood glucose concentrations must be monitored when gastric motility is evaluated in diabetic patients. There is a poor relationship between gastric emptying and gastrointestinal symptoms and the mechanisms by which abnormal motility causes symptoms are unclear. The introduction of new gastrokinetic drugs has improved therapeutic options for the management of symptomatic patients with gastroparesis considerably. The contribution of disordered gastric emptying to poor glycaemic control is unclear, but the demonstration that the rate of gastric emptying is a major factor in normal blood glucose homeostasis suggests that this is likely to be significant.

Effect of single dose of oral erythromycin on gastric and gallbladder emptying. Simultaneous assessment by ultrasound

To evaluate the effects of a single oral dose of erythromycin on gastric and gallbladder emptying, 10 volunteers, without a known history of gastrointestinal disease, were investigated. Erythromycin stearate (500 mg) or placebo was given on separate mornings 30 min before a standard solid meal in a randomized, double-blind, crossover study. Gastric and gallbladder emptying rates were simultaneously evaluated by means of real-time ultrasonography. Gastric antral area and gallbladder volume were determined before the meal and 30, 60, 120, 180, 240, and 300 min after commencing eating. Erythromycin, compared to placebo, significantly accelerates and increases the degree of both gastric and gallbladder emptying. As previously reported for intravenous and chronic oral assumption, also a single dose of oral erythromycin is able to accelerate gastric and gallbladder emptying in normal human subjects.

Gastric emptying of solid meals in achalasic patients after successful pneumatic dilatation of the cardia

Gastric emptying of a solid meal was measured by ultrasound scanning in 16 achalasic patients following successful pneumatic dilatation of the lower esophageal sphincter. The data were compared with those of a control group of 15 healthy subjects. Fasting and maximal postcibal antral sections were very similar in the two groups. On the contrary, the time interval before maximal antral dilatation, and the time necessary for the emptying of half or of the whole meal were significantly longer in the achalasic patients than in the controls. Half of the achalasic patients had longer emptying times than the upper normal limit. The percentage of the meal retained in the antrum at each hourly interval was significantly higher in the achalasic group. The finding of a high prevalence of gastric emptying disturbances suggests that the functional derangement in achalasia is not limited to the esophagus.

Migrating motor complex recorded spontaneously and induced by motilin and erythromycin in an ex vivo rabbit intestinal preparation

We investigated basal motility and the motor effects of motilin, erythromycin, and prostigmine on segments of rabbit gastrointestinal tract removed from extrinsic neural and vascular pathway and immersed in an oxygenated organ bath. Motility was recorded by means of four strain gauges sutured on the serosal surface of the segment. During basal recording, clusters of duodenal contractions that propagated distally, resembling phase III activity of migrating motor complex, were seen. Motilin (10(-6) M) and erythromycin (10(-6) M) induced a propagated cluster of contractions similar to the phase III recorded during the basal period. Prostigmine (10(-6) M) induced a simultaneous increase in gastric and small intestinal motility. Atropine (10(-5) M) prevented the motor effect of motilin, erythromycin, and prostigmine. Thus, MMCs do not appear to require central input for initiation and propagation. Motilin and erythromycin stimulate MMCs through an enteric cholinergic mechanism; therefore, the previously reported smooth muscle receptors for both substances were not apparent in the ex vivo preparation.

Erythromycin strengthens the defective lower esophageal sphincter in patients with gastroesophageal reflux disease

Motilin induces phase III activity of the gastrointestinal tract. Erythromycin has a motilin-like effect on the stomach and significantly increases the lower esophageal sphincter (LES) pressure in normal volunteers. This investigation was performed to evaluate the effects of erythromycin on esophageal function in patients with gastroesophageal reflux disease (GERD). Esophageal manometry was performed in 10 GERD patients before and after intravenous infusion of 500 mg of erythromycin. Values are expressed as mean +/- SEM. LES pressure increased from 13.9 +/- 2.9 mm Hg at baseline to 28.9 +/- 3.6 mm Hg after infusion of erythromycin (p < 0.01). The duration of contractions in the proximal, middle, and distal esophagus was significantly prolonged from 3.5 +/- 0.4 seconds, 3.8 +/- 0.4 seconds, and 4.1 +/- 0.5 seconds to 4.2 +/- 0.2 seconds, 4.6 +/- 0.5 seconds, and 5.6 +/- 0.6 seconds, respectively, after infusion of erythromycin (p < 0.05 for each comparison). Erythromycin did not effect esophageal body contraction amplitude or velocity, or the upper esophageal sphincter. Serum motilin decreased slightly after the administration of erythromycin. We concluded the following: (1) Erythromycin profoundly stimulates the defective LES in patients with GERD. This appears to be a direct motilin agonist-like effect rather than being mediated by release of endogenous motilin. (2) Erythromycin has less effect on the esophageal body, although it does prolong the duration of esophageal contractions.

Patients with achalasia lack nitric oxide synthase in the gastro-oesophageal junction

The abnormal function of the lower oesophageal sphincter in achalasia is likely to be due to impaired nonadrenergic, noncholinergic (NANC) inhibitory input. Since recent studies in animals suggest that nitric oxide (NO) is implicated physiologically in the inhibitory responses of the lower oesophageal sphincter, we have investigated whether the synthesis of NO is altered in the gastro-oesophageal junction of patients with achalasia. NO synthase activity was investigated in samples of tissue from the gastro-oesophageal junction obtained during surgery in eight patients with typical achalasia and six non-achalasic controls who underwent oesophagectomy for reasons other than sphincter dysfunction. The NO synthase activity was determined by the transformation of 14C-L-arginine into 14C-L-citrulline in tissue homogenates. In addition, immunohistochemical staining of the tissues was performed using a polyclonal antibody raised against a peptide sequence of rat brain NO synthase. Furthermore, the relaxant response to an exogenous NO donor (sodium nitroprusside, SNP) was measured in vitro in muscle strips obtained from two patients with achalasia and in two non-achalasic controls. NO synthase activity was detected in each of the samples obtained from six control patients (0.59 +/- 0.21 pmol mg-1 min-1; mean +/- SE). By contrast, none of the samples obtained from the eight patients with achalasia had any detectable NO synthase activity. Immunohistochemical studies confirmed the presence of NO synthase in the myenteric plexus of the gastro-oesophageal junction of control patients and its absence in achalasia. SNP relaxed muscle strips precontracted with bethanechol in both control samples and those from patients with achalasia.(ABSTRACT TRUNCATED AT 250 WORDS)

Erythromycin accelerates gastric emptying after pancreaticoduodenectomy. A prospective, randomized, placebo-controlled trial

OBJECTIVE

This study tested the hypothesis that erythromycin, a motilin agonist, reduces the incidence of early DGE after pancreaticoduodenectomy.

SUMMARY BACKGROUND DATA

Delayed gastric emptying (DGE) is a leading cause of morbidity after pancreaticoduodenectomy, occurring in up to 40% of patients. The pathogenesis of DGE has been speculated to involve factors such as peritonitis from anastomotic leaks, ischemia to the antropyloric muscles, and gastric atony in response to resection of the duodenal pacemaker or reduction in circulating motilin levels.

METHODS

Between November 1990 and January 1993, 118 patients undergoing pancreaticoduodenectomy completed this prospective, randomized, placebo-controlled trial. The patients received either 200 mg of intravenous erythromycin lactobionate every 6 hours (n = 58), or an identical volume of 0.9% saline (n = 60) from the third to tenth postoperative days. On the tenth postoperative day, a dual phase radionuclide gastric emptying study was performed.

RESULTS

The erythromycin and control groups were comparable regarding multiple preoperative, intraoperative, and postoperative factors. The erythromycin group had a 37% reduction in the incidence of DGE (19% vs. 30%), a significantly reduced (p < 0.05) need to reinsert a nasogastric tube for DGE (6 vs. 15 patients), and a significantly reduced (p < 0.01) per cent retention of liquids at 30 minutes and solids at 30, 60, 90, and 120 minutes. No major adverse reactions to erythromycin were observed.

CONCLUSIONS

Erythromycin is a safe, inexpensive drug that significantly accelerates gastric emptying after pancreaticoduodenectomy and reduces the incidence of DGE by 37%. These data support the use of erythromycin to decrease early DGE after pancreaticoduodenectomy.

Organization of antral, pyloric and duodenal motility in patients with gastroparesis

The motor mechanisms associated with delayed gastric emptying are poorly understood, and the contribution of abnormal patterns of gastroduodenal motility to gastroparesis is unknown. Limited data suggest an increased frequency of localized pyloric contractions contributes to delayed gastric emptying. Antropyloroduodenal pressures and gastric emptying of 99mTc chicken liver/ground beef were recorded simultaneously for 60 min in 16 patients with gastroparesis and 26 healthy subjects, using a sleeve/sidehole manometric assembly and a scintigraphic technique. Manometric recordings were analysed for localized pyloric contractions (isolated pyloric pressure waves), basal pyloric pressure (tone), antral and duodenal pressure waves and the number of associated antropyloroduodenal contractions ≥6 cm in length. There was no significant difference in median pyloric tone (1.1 (interquartile range 0.3–2.1) vs 0.5 (0–1.8)mmHg), number of isolated pyloric pressure waves (15 (4.5–25) vs 25 (12–37)) or antral pressure waves (47 (16–62) vs 46 (17–76) between the patients with gastroparesis and the healthy controls. The number of duodenal pressure waves was significantly less in the gastroparetics (54 (41–80) vs 102 (63–116), P < 0.05) as was the number of antropyloroduodenal pressure waves ≥6 cm (5 (0.5–6) vs 12.5 (4–24), P < 0.05). There was no difference in the lag time for solid gastric emptying, but there was a reduction in the amount emptied after 60 min (1 (0–10) vs 10 (0–14)%, P < 0.01). These results suggest that abnormal patterns of antropyloroduodenal contractions contribute to slow gastric emptying in patients with gastroparesis. Localized pyloric contractions are not a major pathogenetic mechanism.

5-hydroxytryptamine-3 receptors are involved in the initiation of gastric phase-3 motor activity in humans

BACKGROUND

5-hydroxytryptamine-3 (5-HT3) receptor antagonists inhibit gastric phase-3 motor activity in the dog. This study examined the role of 5-HT3 receptors in the generation of gastric phase 3 of the migrating motor complex in humans.

METHODS

Interdigestive motor activity was recorded manometrically in 16 subjects before and after administration of ondansetron, a selective 5-HT3 receptor antagonist. Plasma motilin values were also assayed in 7 individuals. The incidence of gastric activity fronts before and after ondansetron was compared with a control group that had not received ondansetron. The ability of erythromycin to induce a gastric activity front in the presence of ondansetron was also evaluated in 7 subjects.

RESULTS

The incidence of gastric activity fronts was 69% before ondansetron vs. 19% after ondansetron. In contrast, in the control group there was no significant change in the incidence of gastric activity fronts over time. Activity fronts preceding ondansetron were associated with motilin peaks while activity fronts after ondansetron were not. Despite the previous administration of ondansetron, erythromycin induced gastric activity fronts in 89% of cases.

CONCLUSIONS

Selective antagonism of 5-HT3 receptors suppresses the gastric component of phase-3 motor activity and simultaneously suppresses plasma motilin peaks. The results suggest that the suppression of gastric activity fronts is achieved via the suppression of plasma motilin peaks because in the presence of ondansetron a motilin agonist like erythromycin restores the gastric phase 3.

Macrolide antibiotics as antiinflammatory agents: roxithromycin in an unexpected role

The antiinflammatory activity of a new 14-membered macrolide antibiotic, roxithromycin, was evaluated in various rat models including carrageenan- and poly-L-arginine-induced hind-paw oedema, croton oil inflamed ear assay and polyester sponge granuloma. When administered orally to animals, roxithromycin displayed an atypical profile in the assays utilized, including: (1) marked antioedema activity similar to that of indomethacin in poly-L-arginine assay, (2) significant inhibition of lambda-carrageenan hind-paw oedema and croton-oil-induced inflammation in the ear, although indomethacin was more effective, and (3) failure to reduce the development of granuloma induced by implanted polyester sponges, while indomethacin significantly reduced the chronic inflammatory reaction. Based on these results, it is concluded that roxithromycin is active in reducing the acute inflammatory reaction in rat models through mechanisms different from conventional nonsteroidal antiinflammatory agents such as indomethacin. Therefore, roxithromycin may have a favorable impact on skin inflammatory reactions accompanying microbial infections.