Hyperglycemia attenuates erythromycin-induced acceleration of solid-phase gastric emptying in healthy subjects

BACKGROUND: Acute hyperglycemia has been associated with delayed gastric emptying of solid foods in healthy control subjects. Erythromycin has been found to be a gastrointestinal prokinetic agent in humans. We examined whether acute steady-state hyperglycemia reduces the erythromycin-induced acceleration of gastric emptying of a solid meal after a fasted state in healthy subjects. METHODS: Twelve healthy subjects ate standard solid meals that had been radiolabeled. Gastric emptying was measured by scintigraphy during normoglycemia (5-8.9 mmol/L glucose) and hyperglycemia induced by intravenous glucose (16-19 mmol/L glucose) after administration of placebo or 200 mg of erythromycin intravenously. Emptying was measured randomly on 4 different days. RESULTS: Administration of erythromycin during normoglycemia or induced hyperglycemia compared with placebo accelerated the gastric emptying of the solid meal but did not completely normalize the delay caused by hyperglycemia versus normoglycemia (p < 0.001). In both conditions, erythromycin versus placebo significantly reduced the lag-phase duration (9.7 +/- 2.3 min and 22.0 +/- 3.9 min vs. 38.3 +/- 5.7 min and 49.5 +/- 6.0 min, respectively; p < 0.001), gastric emptying of the half meal (39.2 +/- 4.0 min and 52.0 +/- 7.1 min vs. 75.7 +/- 11.8 min and 94.0 +/- 13.4 min, respectively; p < 0.001), and the percentage of meal retained in the stomach 120 min postprandially (p < 0.001). CONCLUSION: The erythromycin-induced acceleration effect on gastric emptying was related to the plasma glucose level. Hyperglycemia might have chosen a cholinergic antagonist pathway that delayed gastric emptying of solids. Even though induced hyperglycemia inhibited gastric emptying, erythromycin accelerated the gastric emptying rate through two distinct pathways: cholinergic and noncholinergic.     

Effect of sucralfate and an aluminum hydroxide gel on gastric emptying of solids and liquids

Our purpose was to investigate whether an aluminum-containing compound (sucralfate) and an aluminum-containing antacid (Amphojel; Wyeth Laboratories), both of which are commonly used in peptic ulcer disease, affect gastric emptying. Gastric emptying was studied in ten healthy subjects with the double isotope technique to assess simultaneous emptying rates of the solid and liquid components of a meal. 99mTechnetium sulfur colloid-labeled chicken liver served as the solid component and 111indium diethylenetriamine penta-acetic acid-labeled water was the liquid component. In a randomized, double-blind fashion, 1 gm sucralfate and 30 ml aluminum hydroxide gel were compared with placebo on separate days. Subjects ate the isotope-labeled test meal after dosing, and gastric emptying was monitored for 3 hours by a gamma-camera interfaced with a computer. There was no significant change in gastric emptying of either solids or liquids after sucralfate. The aluminum hydroxide gel slowed the gastric emptying rate for solids more than did the placebo, but this difference was significant only at the intervals of 165 and 180 minutes after the meal. We conclude that aluminum in the form of therapeutic doses of sucralfate does not delay gastric emptying of solids or liquids in normal subjects, while the larger amount of aluminum in therapeutic doses of the antacid gel has some slowing effect on gastric emptying of the solid components of a meal.     

Evaluation of Gastric Emptying by Transabdominal Ultrasound after Oral Administration of Semisolid Cellulose-Based Gastric Ultrasound Contrast Agents

Many previous studies have found that transabdominal ultrasound may allow precise measurement of gastric emptying of liquid meals. However, the clinical use of this technique has been hampered by the limitation that transabdominal ultrasound might not accurately measure gastric emptying of solid meals. It is more important to measure gastric emptying of solids instead of liquids, as gastric emptying of solids is more often delayed than gastric emptying of liquids in gastric motility disorders. Recently, transabdominal ultrasound after oral administration of a cellulose-based gastric contrast agents (TUS-OSCA) has been suggested to be effective in initial screening of gastric lesions. The aim of this study was to explore the accuracy of TUS-OSCA in the evaluation of gastric emptying of a semisolid meal. Twenty healthy young patients (10 males and 10 females aged 25.5?±?2.5 y) were studied. Concurrent measurements of gastric emptying by scintigraphy and TUS-OSCA were performed after ingestion of 350?mL semisolid ultrasound agent labeled with 20 MBq ^99mTc-sulfur colloid. There was no significant difference in the overall curves for gastric emptying time between scintigraphy and TUS-OSCA. There was a good correlation between the gastric 50% emptying times determined by scintigraphy (89.4?±?1.8?min) and TUS-OSCA (92.5?±?1.7?min). The correlation coefficient was r?=?0.922 (p?=?0.000). Current results indicate that TUS-OSCA is accurate, and the results are similar to those obtained by scintigraphy for gastric emptying of a semisolid meal.     

Noninvasive breath tests can detect alterations in gastric emptying in the mouse

BACKGROUND: Noninvasive breath tests may have significant utility for the measurement of gastric emptying in mice, but the tests' sensitivity for detection of changes in gastric emptying has not been evaluated. MATERIALS AND METHODS: Hydroxypropyl methyl cellulose was incorporated into a liquid meal to delay gastric emptying, and mice were injected with erythromycin to accelerate emptying of a liquid or solid meal. All test meals were labelled with (13)C-acetic acid or (13)C-octanoic acid. Breath samples collected at intervals were analysed for (13)CO(2) content, and gastric emptying rates were calculated from the resultant (13)CO(2) excretion curves. RESULTS: As predicted, hydroxypropyl methyl cellulose slowed emptying compared with water (14.21 +/- 0.94 min vs. 9.17 +/- 0.47 min, P < 0.001), while erythromycin treatment accelerated emptying of liquids (10.96 +/- 0.78 min vs. 16.41 +/- 1.94 min, P < 0.05) and solids (108.81 +/- 18.06 vs. 157.95 +/- 12.01 min, P < 0.05) compared with the saline injected controls. CONCLUSIONS: These data indicate that in mice the breath test is sensitive enough to detect differences in gastric emptying induced by meal composition and pharmacological agents. Noninvasive measurement of gastric emptying in mice will be useful as a method to evaluate the effect of nutrients or drugs on the motility of the gastrointestinal tract.     

Effects of a novel cholecystokinin (CCK) receptor antagonist, MK-329, on gallbladder contraction and gastric emptying in humans. Implications for the physiology of CCK.

To explore the physiology of cholecystokinin (CCK) in humans, we investigated the effect on gallbladder contraction and gastric emptying of a recently developed CCK receptor antagonist, MK-329. In a double-blind, four-period crossover study eight subjects received single doses of 0.5, 2, or 10 mg MK-329, or placebo, followed by an intravenous infusion of CCK-8 (30 pmol/kg.h). In placebo-treated subjects gallbladder volumes decreased on average to 43% of initial volumes after 2 h of CCK infusion. MK-329 caused a dose-dependent inhibition of CCK-stimulated gallbladder contraction with 10 mg producing complete blockade (P less than 0.01, cf. placebo). Gallbladder contraction and gastric emptying rates after a mixed meal were then measured in a two-period crossover study. Subjects received placebo or 10 mg of MK-329 2 h before eating. Gastric emptying of both solids and liquids was measured simultaneously by gamma scintigraphy. In placebo-treated subjects plasma CCK levels increased postprandially to 2.3 pM, gallbladder volumes decreased 68.4 +/- 3.8% (SE), and the times for 50% emptying of liquids and solids from the stomach were 58 +/- 10 and 128 +/- 8 min, respectively. In MK-329-treated subjects there was a marked elevation in peak CCK levels to 13.8 pM (P less than 0.01, cf. placebo), and gallbladder contraction was completely inhibited. Solid and liquid emptying rates were unaffected. These findings demonstrate that (a) MK-329 is a potent, orally active antagonist of CCK in humans, and (b) CCK is the major regulator of postprandial gallbladder contraction. These data also support the concept of negative feedback regulation of CCK secretion and suggest that mechanisms other than CCK play a dominant role in the regulation of postprandial gastric emptying rates.     

Predictors of delayed gastric emptying in diabetes.

OBJECTIVE: To define the predictors of the rate of gastric emptying in patients with diabetes. RESEARCH DESIGN AND METHODS: A total of 101 outpatients with diabetes (79 type 1 and 22 type 2) underwent measurements of gastric emptying of a solid/liquid meal (scintigraphy), upper gastrointestinal symptoms (questionnaire), glycemic control (blood glucose concentrations during gastric emptying measurement), and autonomic nerve function (cardiovascular reflexes). RESULTS: The gastric emptying of solid and/or liquid was delayed in 66 (65%) patients. Solid (retention at 100 min 64 +/- 3.2 vs. 50.2 +/- 3.6%, P < 0.005) and liquid (retention at 100 min 22.7 +/- 1.7 vs. 16.0 +/- 1.8%, P < 0.001) gastric emptying was slower in women than in men. Of all upper gastrointestinal symptoms (including nausea and vomiting), only abdominal bloating/fullness was associated with slower gastric emptying (P < 0.005). A multiple regression analysis demonstrated that both abdominal bloating/fullness and female sex were predictors of slower gastric emptying of both solids and liquids. CONCLUSIONS: We conclude that the presence of abdominal bloating/fullness but not any other upper gastrointestinal symptom is associated with diabetic gastroparesis and that gastric emptying is slower in diabetic women than in diabetic men.     

Erythromycin dose of 70 mg accelerates gastric emptying as effectively as 200 mg in the critically ill

Objective To compare the effectiveness of 70-mg and 200-mg doses of intravenous erythromycin in improving gastric emptying in critically ill patients.Design Gastric emptying was measured on consecutive days; day 1 (pre-treatment), day 2 (post-treatment) after an intravenous infusion of either 70 or 200 mg erythromycin or saline placebo (0.9%), in a randomized double-blind fashion.Setting Mixed medical/surgical intensive care unit, tertiary referral.Patients and participants Thirty-five randomly selected, mechanically ventilated, enterally fed critically ill patients (median APACHE II score 19 on admission).Interventions On day 2 either 70 or 200 mg erythromycin or saline was administered intravenously over 20 min.Measurements and results Gastric emptying was measured using the [¹³C]octanoic acid breath test. The gastric emptying coefficient (GEC) and half-emptying time (t_1/2) were calculated from the area under the ¹³CO₂-recovery curve. Pre-treatment gastric emptying measurements were similar in all three patient groups. Treatment with both doses of erythromycin significantly reduced the gastric t_1/2: 70 mg, 98 min (IQR 88–112); 200 mg, 86 min (75–104); vs. placebo, 122 min (102–190) (p<0.05). The GEC was higher with both doses of erythromycin: 70 mg, 3.8 (3.3–4.0); 200 mg, 4.0 (3.6–4.2); vs. placebo, 2.9 (2.5–3.7) (p<0.05). There was no difference in gastric emptying post-treatment between the two doses of erythromycin. The effect of erythromycin was greatest in patients with delayed gastric emptying.Conclusions Treatment with 70 and 200 mg intravenous erythromycin are equally effective in accelerating gastric emptying in the critically ill     

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.     

Delayed gastric emptying and gastric autoimmunity in type 1 diabetes

OBJECTIVE: Delayed gastric emptying and/or gastrointestinal symptoms occur in 30-50% of diabetic patients. Known contributing factors are autonomic neuropathy and acute hyperglycemia, but the role of gastric autoimmunity has never been investigated, although 15-20% of type 1 diabetic patients exhibit parietal cell antibodies (PCAs). We studied gastric motility in diabetes in relation to PCA status, autonomic nerve function, HbA(1c), thyroid-stimulating hormone (TSH), Helicobacter pylori (HP), acid production, and gastric histology. RESEARCH DESIGN AND METHODS: Gastric emptying of solids and liquids (measured by (13)C-octanoic acid and (13)C-glycine breath tests, respectively) was tested in euglycemic conditions in 42 type 1 diabetic patients (male/female: 29/13; 15 PCA+; mean age 40 +/- 15 years; mean HbA(1c) 7.8 +/- 0.9%). Gastrointestinal symptoms, autonomic nerve function (Ewing tests), PCA status (indirect immunofluorescence), gastric histology, and acid secretion (pentagastrin) were assessed. RESULTS: Solid gastric emptying was delayed in 40% and liquid emptying in 36% of patients. Gastric motility did not correlate with symptoms. PCA status, gastric morphology, and acid secretion were similar in those with and without gastroparesis. HbA(1c) level (beta = 1.34, P = 0.011) was the only risk factor for delayed solid emptying in a logistic regression model testing HbA(1c), autonomic nerve function, PCA, HP status, age, sex, diabetes duration, and TSH. Half-emptying time for liquids correlated with TSH level (r = 0.83, P < 0.0001) and autonomic neuropathy score (r = -0.79, P = 0.001). CONCLUSIONS: We found that approximately 50% of type 1 diabetic patients studied had delayed gastric emptying that did not correlate with symptoms. Gastric autoimmunity did not contribute to diabetic gastroparesis. Metabolic control was worse in patients with delayed solid emptying.     

Erythromycin improves gastric emptying in critically ill patients intolerant of nasogastric feeding

OBJECTIVE: To evaluate the effect of intravenous erythromycin on gastric emptying and the success of enteral feeding in mechanically ventilated, critically ill patients with large volume gastric aspirates. DESIGN: Prospective, double-blind, randomized, and placebo-controlled trial. SETTING: General intensive care unit in a university hospital. PATIENTS: Twenty critically ill, mechanically ventilated patients intolerant of nasogastric feeding (indicated by a residual gastric volume of > or =250 mL during feed administration at > or =40 mL/hr). INTERVENTIONS: After a gastric aspirate of > or =250 mL, which was discarded, the enteral feeding was continued at the previous rate for 3 hrs. Intravenous erythromycin (200 mg) or placebo was then administered over 20 mins. The residual gastric contents were again aspirated and the volume was recorded 1 hr after the infusion began. MEASUREMENTS AND MAIN RESULTS: Gastric emptying was calculated as volume of feed infused into the stomach over 4 hrs minus the residual volume aspirated. Mean gastric emptying was 139+/-37 (+/-SEM) mL after erythromycin and -2+/-46 mL after placebo (p = .027). Nasogastric feeding was successful in nine of ten patients treated with erythromycin and five of ten who received placebo 1 hr after infusion (chi-square p = .05). CONCLUSION: In critically ill patients who have large volumes of gastric aspirates indicating a failure to tolerate nasogastric feeding, a single small dose of intravenous erythromycin allows continuation of feed in the short term.     

Sequential single doses of cisapride, erythromycin, and metoclopramide in critically ill patients intolerant to enteral nutrition: a randomized, placebo-controlled, crossover study

OBJECTIVE: To evaluate the comparative efficacy of enteral cisapride, metoclopramide, erythromycin, and placebo for promoting gastric emptying in critically ill patients with intolerance to gastric enteral nutrition (EN). DESIGN: A randomized, crossover study. SETTING: Adult medical intensive care unit at a university-affiliated private hospital and trauma intensive care unit at a university teaching hospital. PATIENTS: Ten adult, critically ill, mechanically ventilated patients not tolerating a fiber-containing EN product defined as a single aspirated gastric residual volume >150 mL or two aspirated gastric residual volumes >120 mL during a 12-hr period. INTERVENTIONS: Patients received 10 mg of cisapride, 200 mg of erythromycin ethylsuccinate, 10 mg of metoclopramide, and placebo as 20 mL of sterile water every 12 hrs over 48 hrs. Acetaminophen solution (1000 mg) was administered concurrently. Gastric residual volumes were assessed, and plasma acetaminophen concentrations were serially determined by TDx between 0 and 12 hrs to evaluate gastric emptying. MEASUREMENTS AND MAIN RESULTS: Gastric residual volumes during the study were not significantly different between agents. No differences in area under the concentration vs. time curve or elimination rate constant were identified between agents. Metoclopramide and cisapride had a significantly shorter mean residence time of absorption than erythromycin (6.3+/-4.5 [SEM] mins and 10.9+/-5.8 vs. 30.1+/-4.5 mins, respectively [p<.05]). Metoclopramide (9.7+/-15.3 mins) had a significantly shorter time to peak concentration compared with erythromycin and placebo (60.7+/-8.1 and 50.9+/-13.5 mins, respectively [p<.05]). The time to onset of absorption was significantly shorter for metoclopramide vs. cisapride (5.7+/-4.5 vs. 22.9+/-5.7 mins [p<.05]). CONCLUSION: In critically ill patients intolerant to EN, single enteral doses of metoclopramide or cisapride are effective for promoting gastric emptying in critically ill patients with gastric motility dysfunction. Additionally, metoclopramide may provide a quicker onset than cisapride.     

Erythromycin in the Treatment of Diabetic Gastroparesis

The macrolide antibiotic erythromycin has been known to be associated with increased gastrointestinal motility since its introduction more than 35 years ago. Investigators have, thus, sought to take advantage of this side effect in patients with gastric stasis secondary to long-standing insulin-dependent diabetes mellitus (IDDM). The hormone motilin induces phase 3 contractions of the migrating motor complex (MMC) to induce peristalsis and facilitate gastric emptying in normal subjects. Patients with diabetic gastroparesis lack adequate phase 3 activity to effectively empty gastric contents. Exogenous motilin administered to animals and patients with diabetic gastroparesis has proven useful for promoting gastric emptying. However, motilin is expensive to produce and must be given intravenously. Erythromycin has been shown to induce premature phase 3 activity via stimulation of motilin receptors, so investigators evaluated its efficacy for the treatment of diabetic gastroparesis. Early studies in animals with experimental gastroparesis indicated that erythromycin may be a useful prokinetic agent. Human studies of both intravenous erythromycin and chronic oral erythromycin in patients with diabetic gastroparesis resistant to other prokinetic agents showed that gastric retention was indeed reduced and symptomatic improvement achieved. Even though erythromycin lost some of its prokinetic activity with chronic oral dosing, gastric retention was still significantly reduced compared to placebo or baseline. Although prokinetic agents like metoclopramide, domperidone and cisapride are effective for the treatment of patients with diabetic gastroparesis, tachyphylaxis and adverse effects are obstacles to their use. Erythromycin appears to be both effective and well tolerated in clinical studies. At this time it should be reserved for the treatment of patients with diabetic gastroparesis who are resistant to or intolerant of other prokinetic agents. Future research on erythromycin's long-term safety and comparative efficacy will further define its role.     

Pooled Analysis of Gastric Emptying in Patients With Obesity: Implications for Oral Absorption Projection

PurposeGastric emptying time is one of limiting factors that determines the pharmacokinetic properties of drugs administered by mouth. Despite the high prevalence of obesity worldwide, modifications in gastric emptying time have not been systematically addressed in this set of patients. The current analysis aims to quantitatively address obesity-related changes in gastric emptying time of solids, semisolids, and liquids compared with lean individuals, highlighting the relevant pharmacokinetic implications of oral drug absorption in patients with obesity.MethodsWe searched the Cochrane Library, PubMed, Web of Science, and Embase for all relevant articles published until November 1, 2020. Differences in gastrointestinal variables in relation to gastric emptying between obese and lean individuals were quantified by weighted mean difference (WMD) and ratio of means (RoM). Robustness of the analyses was evaluated by subgroup analysis and publication bias test.FindingsA total of 17 studies with 906 participants were included. The gastric half-emptying time of solids (WMD, −10.4 minutes; P = 0.001; RoM, 0.90; P = 0.01) and liquids (WMD, −6.14 minutes; P < 0.001; RoM, 0.83, P = 0.03) was significantly shorter in individuals with obesity compared with lean individuals. These findings were confirmed by the subgroup analyses and publication bias tests.ImplicationsOur pooled analysis systemically quantifies the differences in gastric half-emptying time between individuals with obesity and lean individuals, facilitating better understanding and prediction of drug absorption in individuals with obesity through physiologically based pharmacokinetic approaches. Obesity is associated with a faster transit of both solids and liquids through the stomach.     

Prolongation of gastric emptying by oral propantheline.

The present study shows that a single oral recommended dose of propantheline bromide normally doubles the mean gastric half-emptying time in man. In a prospective, double-blind, randomized crossover design 13 normal subjects were given 30 mg propantheline or placebo 90 min before taking a 113m-indium-labeled liquid test meal, the volume of which was adjusted to body weight. The disappearance of radioisotope from the area of the stomach was determined by external gamma counting. After placebo the mean half-emptying time was 68 min and after propantheline it was 135 min (p less than 0.005). Although salivary flow decreased and pulse rate increased there were no visual disturbances. In studies already reported maximally tolerated oral doses of quaternary ammonium anticholinergic drugs have not consistently retarded gastric emptying in man.     

Effect of sustained-release isosorbide dinitrate on post-prandial gastric emptying and gastroduodenal motility in healthy humans

Nitric oxide (NO) is an inhibitory neurotransmitter released by non-adrenergic and non-cholinergic neurons that innervate the smooth muscles of the gastrointestinal tract. We examined whether NO, derived from a sustained-release preparation of isosorbide dinitrate, influenced gastric emptying and gastroduodenal motility after a meal. Eleven healthy volunteers participated in a double-blind, placebo-controlled, cross-over study. Each subject ingested 40 mg isosorbide dinitrate orally as a sustained-release formulation or oral placebo, in random order. Gastric emptying and gastroduodenal motility were measured using scintigraphic and manometric techniques. Isosorbide dinitrate did not change the area under the curve of gastric retention versus time, and did not influence the frequency of antral contractions as assessed at 15-min intervals or the integrated duodenal motility index, as recorded over consecutive 15-min periods. A 40 mg single dose of sustained-released isosorbide dinitrate does not seem to alter gastric emptying or gastroduodenal motility after a meal.     

ASSESSMENT OF GASTRIC EMPTYING USING GAMMA SCINTIGRAPHY

Gamma scintigraphy was used to measure the gastric emptying rates of three test meals in human volunteers. Emptying rates were determined for solid and liquid materials alone, and for liquid in the presence of solid material. It was shown that the emptying of solids from the stomach was significantly slower than that of liquid, whether liquid alone or liquid in the presence of solid material. It was concluded from these results that, in the case of a solid test meal from which radio-label could be eluted, the free label would empty considerably faster than the remaining solid material. The emptying rate observed scintigraphically would not, therefore, be a true estimate of the solid emptying rate.     

Hyperglycemia attenuates the gastrokinetic effect of erythromycin and affects the perception of postprandial hunger in normal subjects.

OBJECTIVE: The major aims of this study were to determine in normal subjects whether the effects of erythromycin on gastric emptying, postprandial hunger, and fullness are modified by the blood glucose concentration. RESEARCH DESIGN AND METHODS: A total of 10 normal subjects (aged 20-39 years) underwent concurrent measurements of gastric emptying, blood glucose, hunger, and fullness on four separate occasions: twice during euglycemia (approximately 4 mmol/l) and twice during hyperglycemia (approximately 15 mmol/l). Either erythromycin (3 mg/kg) or saline (0.9%) was administered intravenously immediately before ingestion of a radioisotopically labeled solid meal. RESULTS: Gastric emptying was slower (P < 0.0001) during hyperglycemia when compared with euglycemia after both erythromycin and saline administration. During hyperglycemia, erythromycin reduced the lag phase (77.8 +/- 12.6 vs. 20.3 +/- 7.3 min; P < 0.05) but had no effect on the postlag emptying rate (0.32 +/- 0.077% per min vs. 0.24% per min). Hunger decreased (P < 0.001) and fullness increased (P < 0.001) after the meal. Postprandial hunger was less during hyperglycemia after saline infusion (P < 0.05) but not after erythromycin. Hunger was greater after erythromycin during both hyperglycemia and euglycemia (P < 0.05). CONCLUSIONS: At a blood glucose concentration of approximately 15 mmol/l, 1) gastric emptying of a solid meal is slower, when compared with euglycemia, even after administration of erythromycin; 2) the effect of erythromycin on gastric emptying of a solid meal is attenuated; and 3) the perception of postprandial hunger is reduced.     

Gastric motility evaluated by electrogastrography and alternating current biosusceptometry in dogs

Association techniques could be the answer for evaluating electromechanical coupling and gastric emptying under basal conditions and after administration of drugs. Electrogastrography (EGG) and alternating current biosusceptometry (ACB) emerged due to their interesting nature, noninvasiveness and low cost. The aims were to examine in dogs the effect of erythromycin on gastric emptying by ACB and electrical and motor responses to erythromycin and propranolol by ACB and EGG respectively. Twelve beagle dogs ingested a solid test meal on separate days. Under anesthesia, gastric motility was evaluated by EGG and ACB after erythromycin and propranolol administration. Without anesthesia, gastric emptying was assessed under basal conditions and after erythromycin by ACB. ACB and EGG showed a strong temporal correlation. Erythromycin and propranolol presented the same profile with different power ratios; the amplitude increased whereas frequency decreased. Also, erythromycin administration hastened gastric emptying while reducing the orocaecal transit time. There is a demand for reliable, easy-to-perform and comfortable techniques to record gastric emptying and gastric activity in medicine and veterinary practice. In summary, the association of ACB with EGG accompanied by an appropriate animal model is promising for evaluating effects of drugs in gastric myoelectrical and contractile activity.     

Effects of oral potassium supplements on upper gastrointestinal mucosa: multicenter clinical comparison of three formulations and placebo

In a carefully controlled multicenter investigation of the effects of oral potassium chloride (KCl) supplements on the gastrointestinal mucosa, 120 healthy men with no endoscopically apparent gastrointestinal lesions were confined to a research ward for 18 days. By random assignment, they were given 60 mEq/day (20 mEq TID) of KCl as either a microencapsulated gelatin capsule, a wax/polymer matrix tablet, or a powder-in-liquid formulation or a placebo capsule for two weeks. All subjects were given glycopyrrolate concomitantly to delay gastric emptying. After treatment was completed, endoscopic examinations of the esophagus, stomach, and duodenum were performed and evaluated by specialists blinded to the particular treatment given. Mild to moderate gastrointestinal irritation, characterized by erythema and edema, was found with similar frequency in all four treatment groups. Two of 30 subjects given the microencapsulated KCl had a single erosion each. Single or multiple erosions were also observed in 14/30 men given the wax/polymer matrix tablet, in 7/30 given the powder, and in 1/30 given placebo. One subject given the wax/polymer matrix tablet had a gastric ulcer. The incidence of gastrointestinal injury with the microencapsulated form was significantly less (P less than 0.01) than that with the wax/polymer matrix tablet and was not significantly different from that seen with either the powder or placebo.     

Changes in gastric emptying rates with age

A dual isotope technique which measures simultaneously the emptying of solids and liquids by the stomach was used to study gastric emptying in 35 subjects in the age range 21-84 years, who were all fit, mobile volunteers and were not taking any drugs. Solid and liquid emptying were significantly slower in older subjects, but this finding is unlikely to be of clinical significance because the changes were small and emptying rates were usually within the normal range for younger subjects.