Cisapride: a gastrointestinal prokinetic drug

Prucalopride reduces the number of reflux episodes and improves subjective symptoms in gastroesophageal reflux disease: a case series

Introduction

Treatment of persistence to proton pump inhibitors or non-acid reflux episodes in patients with gastroesophageal reflux disease is challenging. Prucalopride, a selective high affinity serotonin (5-HT₄) receptor agonist, might offer a possible new therapeutic alterative.

Case presentations

We report four chronically constipated female gastroesophageal reflux disease-patients with reflux symptoms and an increased number of reflux episodes in combined esophageal pH and multichannel impedance monitoring treated with prucalopride (2mg per day). Symptoms were persistent to proton pump inhibitors and ranitidine. Gastroesophageal reflux was detected by pH or multichannel impedance (MII) monitoring. Numbers of all reflux episodes as well as non-acid reflux episodes were reduced in all of our patients. The objective findings were concordant with subjective reports of symptom relief. There were no major adverse events in any patient during therapy with prucalopride.

Conclusion

Administration of prucalopride showed promising results in the treatment of persisting or weakly and/or non-acid reflux episodes in our case series in four constipated patients. Therefore, prucalopride can be regarded as a possible therapeutic option in the treatment of standard proton pump inhibitor-persistent reflux in the chronically constipated patient. However, further prospective trials are needed to prove our findings.

Luteolin reduces high glucose-mediated impairment of endothelium-dependent relaxation in rat aorta by reducing oxidative stress

While luteolin, a flavone rich in many plants, has some cardiovascular activity, it is not clear whether luteolin has beneficial effects on the vascular endothelial impairment in hyperglycemia/high glucose. Here, we reveal the protective effect of luteolin on endothelium-dependent relaxation in isolated rat aortic rings exposed to high glucose. The thoracic aorta of male Sprague-Dawley rats was rapidly dissected out and the effect of luteolin on the tension of aortic rings pretreated with high glucose (44mM) for 4h was measured in an organ bath system. The levels of nitric oxide (NO), hydroxy radical (OH(-)) and reactive oxygen species (ROS), and the activity of superoxide dismutase (SOD) and nitric oxide synthase (NOS) were measured in aortas. The vasorelaxation after treatment with luteolin for 8 weeks in aortic rings from diabetic rats was also determined. We found that exposure to high glucose decreased acetylcholine-induced endothelium-dependent relaxation. However, high mannitol had no effect on vasorelaxation. Luteolin evoked a concentration-dependent relaxation in aortic rings previously contracted by phenylephrine, and the pD(2) value was 5.24+/-0.04. The EC(50) of luteolin markedly attenuated the inhibition of relaxation induced by high glucose, which was significantly weakened by pretreatment with l-NAME (0.1mM), but not by indomethacin (0.01mM). Luteolin significantly inhibited the increase of ROS level and OH(-) formation, and the decrease of NO level, NOS and SOD activity caused by high glucose. The improving effect of luteolin on endothelium-dependent vasorelaxation in diabetic rat aortic rings was reversed by pretreatment with l-NAME or methylene blue. The results indicate that the decrease of endothelium-dependent relaxation in rat aortic rings exposed to high glucose is markedly attenuated by luteolin, which may be mediated by reducing oxidative stress and enhancing activity in the NOS-NO pathway.

Colonic treatments and targets: issues and opportunities

The colon provides a plethora of therapeutic opportunities. There are multiple disease targets, drug molecules, and colon-specific delivery systems to be explored. Clinical studies highlight the potential for systemic delivery via the colon, and the emerging data on the levels of cell membrane transporters and metabolic enzymes along the gut could prove advantageous for this. Often efflux transporters and metabolic enzyme levels are lower in the colon, suggesting a potential for improved bioavailability of drug substrates at this site. The locoregional distribution of multiple metabolic enzymes (including cytochromes), efflux transporters (including P-glycoprotein and breast cancer resistance proteins), and influx transporters (including the solute carrier family) along the intestine is summarized. Local delivery to the colonic mucosa remains a valuable therapeutic option. New therapies that target inflammatory mediators could improve the treatment of inflammatory bowel disease, and old and new anticancer molecules could, when delivered topically, prove to be beneficial adjuncts to the current systemic or surgical treatments. New issues such as pharmacogenomics, chronotherapeutics, and the delivery of prebiotics and probiotics are also discussed in this review. Targeting drugs to the colon utilizes various strategies, each with their advantages and flaws. The most promising systems are considered in the light of the physiological data which influence their in vivo behavior.

QT interval prolongation in future SIDS victims: a polysomnographic study

OBJECTIVE

Previous data have suggested that a prolonged QTc interval during the first days of life can be associated with some cases of sudden infant death syndrome (SIDS). Analysis of heart rate variability during sleep in future SIDS victims has shown findings compatible with an imbalance in autonomic tone. We hypothesized that some future SIDS infants could have longer QTc intervals during sleep, compared with healthy control infants, and that this difference would correlate with the autonomic imbalance already found in these infants.

METHODS

QTc intervals and a heart rate autoregressive power spectral analysis were calculated during the same periods in the polysomnographic sleep recordings of 18 infants who eventually died of SIDS and of 18 control infants. The control infants were matched for sex, gestational age, postnatal age, birth weight, and sleep position. The median postnatal age was 8 weeks.

RESULTS

Compared with control infants, future SIDS victims were characterized by having longer QTc intervals during total sleep (P = 0.019), rapid eye movement sleep (P = 0.045) and non-rapid eye movement sleep (P = 0.029). When the night was divided into 3 equal parts, this difference was always present but was most marked during the last part of the night. There was, respectively, a negative and a positive correlation between parasympathetic activity and sympathovagal balance and median and maximum QTc interval values.

CONCLUSION

Compared with QTc intervals in matched control infants, QTc intervals were increased in future SIDS victims. Such a prolongation could be related to the autonomic dysfunction already reported in these patients.

Relationship between acceleration of gastric emptying and oesophageal acid exposure in patients with endoscopy-negative gastro-oesophageal reflux disease

OBJECTIVE

A delay in gastric emptying has been reported in patients with gastro-oesophageal reflux disease (GORD), but its role in increasing the number of reflux episodes is still debated. The aim of this study was to assess the relationship between acceleration of gastric emptying and gastro-oesophageal reflux in patients with endoscopy-negative GORD and pathological oesophageal acid exposure.

MATERIAL AND METHODS

Twelve patients (7 M, age range 24-65 years) underwent 6-h postprandial (2.1 MJ meal) combined gastric emptying by real-time ultrasonography and intra-oesophageal pH monitoring after cisapride (20 mg b.i.d.) and placebo for 3 days, on two separate occasions at least 7 days apart in double-blind randomized order. Gastric emptying after placebo was also measured in 12 healthy volunteers (7 M, age range 25-54 years).

RESULTS

In the patients' group, the area under the emptying time curve was greater (p<0.01), and half and total emptying times prolonged (p<0.01) compared to the healthy subjects, 115 min (mean)+/-6 (SEM) versus 86+/-6 and 232 min+/-16 versus 160+/-7, respectively. Cisapride accelerated both half- and total gastric emptying (p<0.02): -22 min (mean); -10 to -34 (95% CI) and -48 min; -10 to -85, respectively, decreased both percentage of time at pH < 4 (p<0.01) and number of reflux episodes (p<0.05). However, no relationship was found between changes in gastric emptying and in the reflux variables by linear regression analysis (R2<0.005).

CONCLUSION

The emptying rate of the whole stomach is not a major determinant of gastro-oesophageal reflux.

Effect of Anticholinergics (Atropine, Glycopyrrolate) and Prokinetics (Metoclopramide, Cisapride) on Gastric Motility in Beagles and Labrador Retrievers

The effect of atropine, glycopyrrolate, metoclopramide and cisapride on the antral motility was investigated in eight dogs (four Beagles and four Labradors) using passive telemetry. Both anticholinergics induced a pronounced and lasting reduction of the intensity and frequency of the contractions. A definite dose-related inhibition of the antral motility was seen in Beagles, similar for both active substances. Low doses of atropine (0.02 mg/kg BW i.m.) and glycopyrrolate (0.005 mg/kg BW i.m.) completely inhibited the gastric motility for at least 30 min, whereas higher doses (0.04 or 0.01 mg/kg BW) caused a cessation of activity for more than 3 h. In Labradors, the effects of both active substances were not so dose related and the effect of glycopyrrolate lasted at least 6 h, whereas the effect of atropine gradually decreased after 3 h. A distinct breed difference regarding the effect of the two prokinetics on the antral motility was also observed. In Beagles, the prokinetics, at a low dose (metoclopramide 0.3 mg/kg BW, cisapride 0.2 mg/kg BW), resulted in a significant increase in the amplitude integral. Higher doses (metoclopramide 0.6 mg/kg BW, cisapride 0.5 mg/kg BW) also increased the integrals of the pressure profiles, but significantly less than with the lower doses. In Labradors, both medications, mainly at higher doses, resulted in an increase of the contraction amplitudes. The low dose had no (cisapride) or only a transient effect (metoclopramide). The frequency of the antral contractions was not at all influenced by cisapride, and only in Beagles metoclopramide resulted in a dose-related increase. It is not clear if the different results in Labradors and Beagles are because of breed or body weight.

Measurement of 5-HT4 receptor-mediated esophageal responses by digital sonomicrometry in the anesthetized rat

INTRODUCTION

In vitro studies have demonstrated a 5-HT4 receptor-mediated relaxation of the pre-contracted rat esophagus. However, it is unclear whether 5-HT4 receptor agonists affect resting esophageal tone in vivo. The activity of 5-HT and several well-established 5-HT4 receptor agonists (tegaserod, BIMU-8, cisapride, renzapride, and mosapride) was investigated in a novel in vivo model designed to measure esophageal relaxation using the technique of digital sonomicrometry.

METHODS

Miniature piezo-electric crystals were implanted externally in a longitudinal orientation on the distal esophagus of isoflurane-anesthetized, adult male Sprague-Dawley rats. Measurement of the time for transmission of ultrasonic pulses between the implanted crystals provided a continuous recording of inter-crystal distance and hence esophageal muscle length.

RESULTS

Following cumulative intravenous administration, 5-HT (1-100 microg/kg), tegaserod (1-1000 microg/kg), BIMU-8 (3-3000 microg/kg), renzapride (10-3000 microg/kg), cisapride (30-3000 microg/kg), and mosapride (30-10,000 microg/kg) produced a dose-dependent increase in esophageal inter-crystal distance. The mean ED50 values for tegaserod, BIMU-8, renzapride, cisapride, and mosapride were 11, 49, 51, 141, and 1825 microg/kg, respectively. Pre-treatment with the selective 5-HT4 receptor antagonist, piboserod (SB-207266; 1 mg/kg subcutaneously) significantly attenuated the effects of intravenous tegaserod (1-1000 microg/kg). Following cumulative intraduodenal administration (0.03-10 mg/kg), tegaserod and mosapride exhibited a dose-dependent increase in esophageal inter-crystal distance. The doses associated with a 10% increase in muscle length from the resting level were 2.6 and>10 mg/kg for tegaserod and mosapride, respectively.

DISCUSSION

In conclusion, dose-dependent, 5-HT4 receptor agonist-mediated increases in longitudinal muscle length in the rat esophagus were observed in vivo using the technique of digital sonomicrometry. This in vivo model of esophageal activity may prove useful in evaluating the activity of novel 5-HT4 receptor agonists.

Determination of cisapride, its oxidation product, propyl and butyl parabens in pharmaceutical dosage form by reversed-phase liquid chromatography

A simple, rapid and reproducible high-performance liquid chromatography (HPLC) assay for cisapride, its oxidation product (OP), propyl and butyl parabens in a pharmaceutical formulation is described. Chromatography was performed at room temperature by pumping acetonitrile-20 mM phosphate buffer pH 7 (50:50, v/v) at 1.5 ml min(-1) through C8 reversed-phase column. Cisapride, OP, propyl and butyl parabens were detected at 276 nm and were eluted at 9.7, 3.1, 5.1 and 7.1 min, respectively. Calibration plots were linear (r>0.999) for all compounds from 0.5 to 200 microg ml(-1) for cisapride and OP and 0.1-200 microg ml(-1) for propyl and butyl parabens. Detection limits for cisapride, OP, propyl and butyl parabens were 40, 46, 48 and 54 ng ml(-1), respectively. Forced degradation investigations showed that cisapride does not undergo degradation under heat, acidic and basic conditions but it was susceptible to oxidation. The proposed method was successfully applied to the assay of cisapride in the presence of preservatives and OP in a commercial suspension.

Current concepts in diabetic gastroparesis

Diabetic gastroparesis is a common and debilitating condition affecting millions of patients with diabetes mellitus worldwide. Although gastroparesis in diabetes has been known clinically for more than 50 years, treatment options remain very limited. Until recently, the scientific literature has offered few clues regarding the precise aetiology of gastric dysfunction in diabetes.Up to 50% of patients with diabetes may experience postprandial abdominal pain, nausea, vomiting and bloating secondary to gastric dysfunction. There is no clear association between length of disease and the onset of delayed gastric emptying. Gastroparesis affects both type 1 (insulin dependent) and type 2 (non- insulin dependent) forms of diabetes. Diagnosis requires identifying the proper symptom complex, while excluding other entities (peptic ulcer disease, rheumatological diseases, medication effects). The diagnosis of gastroparesis may be confirmed by demonstrating gastric emptying delay during a 4-hour scintigraphic study. Treatment options are limited and rely on dietary modifications, judicious use of available pharmacological agents, and occasionally surgical or endoscopic placement of gastrostomies or jejunostomies. Gastric pacing offers promise for patients with medically refractory gastroparesis but awaits further investigation. Current pharmacological agents for treating gastroparesis include metoclopramide, erythromycin, cisapride (only available via a company-sponsored programme) and domperidone (not US FDA approved). All of these drugs act as promotility agents that increase the number or the intensity of gastric contractions. These medications are not uniformly effective and all have adverse effects that limit their use. Cisapride has been removed from the open market as a result of over 200 reported cases of cardiac toxicity attributed to its use. Unfortunately, there is a paucity of clinical studies that clearly define the efficacy of these agents in diabetic gastroparesis and there are no studies that compare these drugs to each other. The molecular pathophysiology of diabetic gastroparesis is unknown, limiting the development of rational therapies. New studies, primarily in animals, point to a defect in the enteric nervous system as a major molecular cause of abnormal gastric motility in diabetes. This defect is characterised by a loss of nitric oxide signals from nerves to muscles in the gut resulting in delayed gastric emptying. Novel therapies designed to augment nitric oxide signalling are being studied.

High performance liquid chromatographic determination, pharmacokinetic and comparative bioavailability studies of cisapride

A sensitive and specific reversed phase HPLC method was developed to quantitate plasma levels of cisapride in order to conduct comparative bioavailability studies. The drug and internal standard was extracted from plasma with heptane-isoamyl alcohol (95:5 v/v) and back extracted with sulfuric acid. The acidic layer was then re-extracted with the same extracting solvent. The separated organic layer was evaporated to dryness under nitrogen and the residue reconstituted with acetonitrile. Analysis was performed on a C-8 Sil-X-10 HPLC column, with a mobile phase of acetonitrile, water, and triethylamine (75:25:0.01) and UV detection at 215 nm. The standard curve covering the concentration range 5-160 ng/ml was linear (r(2)=0.9992), relative errors were within +/-10% and the CV% ranged from 1.34 to 11.82. The in vivo study was carried out in 12 healthy volunteers according to a single dose, two-sequence, cross over randomized design. The bioavailability was compared using the total area under the plasma level versus time curve (AUC(0-34,) AUC(0- infinity )), peak plasma concentration (C(max)) and time to C(max) (T(max)). No statistically significant difference was found between the AUC(0- infinity ) or C(max) values of the test (cisapride) and reference (Propulsid). It was, therefore, concluded that the generic cisapride was bioequivalent with the innovator formulation.

The Effect of Cisapride on the Success of Early Feeding after Elective Open Colon Resection

Early postoperative feeding after open colon resection has been shown to be safe and effective. However, approximately 13 per cent of patients fail to tolerate it. We hypothesized that the use of promotility agents may decrease failure of early postoperative feeding after elective open colectomy. As part of a consecutive case series metoclopramide or cisapride was administered to patients undergoing open colectomy as part of an early feeding protocol. The early feeding protocol consisted of instituting a clear liquid diet on postoperative day (POD) 2, followed by a regular diet on POD 3. One hundred fifty-one patients received early feeding without promotility agents (Group I). The next 49 patients were treated with metoclopramide (Group II), and 31 patients received cisapride (Group III). In Group I 20 of 151 patients (13.2%) failed early feeding, and the mean hospital stay was 3.77 days (range 3–11 days). In Group II seven of 49 patients (14.2%) failed early postoperative feeding, and the mean hospital stay was 3.67 days (range 3–8 days). Group III had no patients who failed to tolerate early feeding, and the mean hospital stay was 3.32 days (range 3–5 days). There were no anastomotic leaks or abdominal abscesses in any group. No caridac arrhythmias were associated with cisapride. A decrease in early feeding failure was observed with cisapride administration.

Pharmacology for the gastrointestinal tract

A variety of drugs are used in the neonatal nursery for the management of feeding intolerance, gastroesophageal reflux, and acid-related disease. Although the pharmacokinetics of some of these drugs have been described in infants and older children, further data are needed, particularly for preterm infants. No data are available characterizing the disposition of the proton pump inhibitors, which will likely be used in infants with refractory, acid-related disease. Further data are also needed to characterize fully the pharmacodynamics, or efficacy, of many of the commonly used drugs.

QTc interval in infants receiving cisapride

OBJECTIVE

To examine the effect of cisapride on the corrected QT (QTc) interval in infants over a 14-day period.

STUDY DESIGN

A prospective cohort study of infants receiving cisapride (0.8 mg/kg per day). Twelve-lead electrocardiograms were obtained before and 3, 5, 7, and 14 days after cisapride initiation.

RESULTS

Fifty infants completed the study; none had arrhythmias. Fifteen of 50 infants (30%) developed QTc interval > or =450 msec; QTc interval normalized in 13 of 15 infants. Infants with QTc interval on day 3 > or =2 standard deviations above the mean baseline QTc interval (401+40 msec) were more likely to develop prolonged QTc interval (p<0.0001).

CONCLUSION

QTc interval prolongation was noted in 30% of infants. Subsequently, the majority of those infants had QTc interval normalization by day 14 of cisapride therapy. QTc interval 3 days following cisapride initiation may identify infants at risk for transient QTc interval prolongation. With appropriate monitoring, hospitalized infants receiving cisapride may have improved gastrointestinal motility without cardiac morbidity.

Retrospective analysis of the effects of cisapride on the QT interval and QT dispersion in chronic hemodialysis patients

Cisapride is contraindicated in patients with end-stage renal disease (ESRD) and gastrointestinal motility disorders. Ventricular arrhythmias have been associated with both cisapride and hemodialysis (HD). However, reports conflict regarding the safety of cisapride in HD patients. We undertook this study to characterize the effects of cisapride on QT intervals and QT dispersion (QTD) in HD patients. Baseline and steady-state electrocardiograms (ECGs) were retrospectively selected for calendar year 1999 for each patient administered cisapride if ECGs showed sinus rhythm, potassium level was 3.5 mEq/dL or greater, and there was no pharmacokinetic drug interaction. QT intervals were measured by two investigators, and QTDs were calculated (maximum [QT(max)] - minimum QT interval [QT(min)]). Averages between investigator measures (+/- SD), presented for each value, were evaluated using Wilcoxon's signed-rank test. Thirty-one HD patients were administered cisapride. Seventeen patients failed to meet entry criteria, and no patient had a pharmacokinetic drug interaction. In included patients (6 men, 8 women), heart rates were 86.71 +/- 20.87 beats/min at baseline and 86.57 +/- 14.23 beats/min during treatment (P = not significant). Serum potassium levels were 4.97 +/- 1.2 mEq/dL at baseline and 4.94 +/- 0.76 mEq/dL during treatment (P = not significant). Average baseline QT(max) and QT(min) were 391.07 +/- 42.43 and 330.71 +/- 40.94 milliseconds, respectively. Treatment QT(max) and QT(min) were 391.43 +/- 38.2 and 343.93 +/- 35.69 milliseconds, respectively (P = not significant for both). QTD was 60.36 +/- 17.59 milliseconds at baseline and 47.5 +/- 19.59 milliseconds during treatment (P = 0.074). Mean corrected QT (QTc) intervals increased from 426.57 +/- 26.62 to 431.71 +/- 29.98 milliseconds (P = 0.55) from baseline to treatment. No ventricular arrhythmia was observed during at least 160 days (range, 2 to 830 days) of cisapride exposure. Two patients died during this study, both of other causes 4 days after discontinuing cisapride therapy. Cisapride did not significantly increase mean QTc interval, QT(max), or QTD in patients with ESRD managed by HD when potassium levels were stable and pharmacokinetic drug interactions were avoided.

Cisapride associated with QTc prolongation in very low birth weight preterm infants

OBJECTIVE

No systematic study has been performed to evaluate the effect of cisapride on the QT interval in premature infants. Cisapride, which has recently been withdrawn by the Food and Drug Administration and is no longer an approved therapy, was commonly used for preterm infant care to improve the advance of enteral feedings and to reduce reflux and associated apnea. Our aim was to evaluate the effect of recommended doses of cisapride on the QT interval in this population.

STUDY DESIGN

Prospective blinded evaluation of electrocardiogram for QT, JT, QTc, and JTc measurements in 25 preterm infants before and after cisapride administration.

RESULTS

Twelve of 25 infants (48%) developed repolarization abnormalities with cisapride administration: 32% of the infants (8/25) studied had QTc prolongation (>/=0.450 seconds), whereas 10/25 had JTc prolongation (>/=0.360 seconds). Preterm infants <32 weeks significantly prolonged their QTc interval from 0.41 +/- 0.02 to 0.44 +/- 0.02. The QTc and/or JTc was prolonged in 54% of infants receiving 0.1 mg/kg/dose and 42% receiving 0.2 mg/kg/dose.

CONCLUSIONS

The QTc and JTc interval significantly prolonged in preterm infants <32 weeks on the recommended dose of cisapride therapy. A QTc >/=0.450 seconds developed in 32% of infants treated with cisapride, whereas the JTc prolonged in 40%. A significant percentage of infants (54%) developed prolonged QTc intervals at a dose of 0.1 mg/kg/dose. From these data we conclude that there is a higher risk of prolongation of the QTc interval and risk of arrhythmias with greater prematurity.

Influence of coadministration of fluoxetine on cisapride pharmacokinetics and QTc intervals in healthy volunteers

STUDY OBJECTIVE

To evaluate the effect of fluoxetine on the pharmacokinetics and cardiovascular safety of cisapride at steady state in healthy men.

DESIGN

Open-label, three-phase, sequential study.

SETTING

Clinical research center.

SUBJECTS

Twelve healthy male volunteers.

INTERVENTIONS

Each subject was treated according to the following sequence: baseline; phase 1 (days 1-6): cisapride 10 mg 4 times/day; washout (days 7-13); phase 2 (days 14-44): fluoxetine 20 mg/day; and phase 3 (days 45-52): cisapride 10 mg 4 times/day (days 45-51) plus fluoxetine 20 mg/day (days 45-52).

MEASUREMENTS AND MAIN RESULTS

Blood samples were drawn and 12-lead electrocardiograms performed at specified time points after the last morning dose of cisapride in phases 1 and 3. Blood samples also were taken before morning doses on the 3rd, 4th, and 5th days of phases 1 and 3. Electrocardiograms were done at baseline and on the last day of the washout period and phase 2. Coadministration of fluoxetine significantly decreased cisapride plasma concentrations. There were no clinically significant changes in corrected QT intervals during administration of cisapride alone or with fluoxetine. Cisapride was well tolerated when administered alone or with fluoxetine.

CONCLUSION

Cisapride can be administered safely to patients receiving low therapeutic dosages of fluoxetine.

Determination of cisapride in pharmaceutical preparations using derivative spectrophotometry

Derivative spectrophotometric and high performance liquid chromatographic methods (HPLC) were described for the determination of cisapride in pharmaceutical preparations. Spectrophotometrically, cisapride was determined by measuring the 1D-values at 264, 300 nm and 2D-values at 276, 290 and 276-290 nm. Beer's Law was obeyed in the range 2-12 microg ml(-1). The HPLC method depends upon using micropack-Si-10 column at ambient temperature with a mobile phase consisting of methanol-concentrated ammonia (99.25:0.75) at a flow rate of 1 ml min(-1). Quantitation was achieved by UV detection at 272 nm using quinine as internal standard. Calibration curve was linear over the concentration range 2-10 microg ml(-1). Both derivative spectrophotometry and HPLC methods showed good linearity, precision and reproducibility. No interference was found from tablet or suspension matrices at the selected derivative wavelengths and chromatographic conditions. The proposed methods were successfully applied to the assay of commercial tablets and suspension. The procedures were rapid, simple and suitable for quality control applications.

Retrospective analysis of cisapride-induced QT changes in end-stage renal disease patients

BACKGROUND

This study involves a retrospective in-patient chart review of end-stage renal disease (ESRD) patients receiving haemodialysis to observe if cisapride significantly increases heart rate (HR), QT, and corrected QT (QTc) intervals on 12-lead electrocardiograms (ECGs).

METHODS

Medical records for 23 patients who were being treated with chronic maintenance haemodialysis and had >/=2 ECGs while on cisapride and >/=2 ECGs while off cisapride were obtained and reviewed. HR, QT, and QTc on all 12-lead ECGs, reason for admission, and past medical history were analysed.

RESULTS

A total of 529 ECGs (279 on/250 off cisapride) for 23 patients were included. The results, as calculated by each patient's individual averages (n=23), on vs off cisapride respectively, were HR, 88+/-14 vs 84+/-17 beats/min (P:=0.18); QT, 373+/-39 vs 382+/-45 ms (P:=0.24); and QTc, 443+/-27 vs 441+/-21 ms (P:=0.39). No significant difference was found in the number of admissions per month while on or off cisapride. No patient had an average QTc on or off cisapride that was >500 ms. One patient died from ventricular arrhythmia 12 days after discontinuing cisapride. The patient's QTc was significantly longer on vs off cisapride (487 vs 462 ms, P:=0. 007); however, this patient had an extensive cardiac history and multiple syncopal episodes prior to the use of cisapride.

CONCLUSIONS

This study found no significant overall difference in HR, QT, and QTc interval or admissions/month on vs off cisapride in ESRD patients receiving haemodialysis.

Postoperative ileus: a preventable event

BACKGROUND

Postoperative ileus has traditionally been accepted as a normal response to tissue injury. No data support any beneficial effect of ileus and indeed it may contribute to delayed recovery and prolonged hospital stay. Efforts should, therefore, be made to reduce such ileus.

METHODS

Material was identified from a Medline search of the literature, previous review articles and references cited in original papers. This paper updates knowledge on the pathophysiology and treatment of postoperative ileus.

RESULTS AND CONCLUSION

Pathogenesis mainly involves inhibitory neural reflexes and inflammatory mediators released from the site of injury. The most effective method of reducing ileus is thoracic epidural blockade with local anaesthetic. Opioid-sparing analgesic techniques and non-steroidal anti-inflammatory agents also reduce ileus, as does laparoscopic surgery. Of the prokinetic agents only cisapride is proven beneficial; the effect of early enteral feeding remains unclear. However, postoperative ileus may be greatly reduced when all of the above are combined in a multimodal rehabilitation strategy.

Cisapride: the problem of the heart

Cisapride has been used in the neonatal population as a first-line gastrointestinal prokinetic agent for managing feeding intolerance secondary to decreased gastrointestinal motility. Cisapride acts specifically at many levels of the gastrointestinal tract and has no central nervous system side effects. Recently, prolonged QT interval has been reported secondary to high-dose cisapride, and concerns regarding its use in premature infants have been raised. In response, Janssen-Ortho Inc. and Janssen Pharmaceutica, the manufacturers of cisapride in Canada and the U.S., have released safety information prohibiting the use of cisapride in premature infants. In light of the present evidence, it is imperative that NICUs that continue to prescribe cisapride for the management of feeding intolerance exercise vigilance in cardiac monitoring and recognize the importance of drug interactions that lead to elevated cisapride levels.

Randomised controlled trial of cisapride in preterm infants

AIM

To determine the effect of cisapride on gastrointestinal motility in preterm infants.

METHODS

Cisapride (0.2 mg/kg, 8 hourly ) or placebo was given first for seven days in a double blind randomised crossover study of 10 preterm infants. Gastrointestinal motility was assessed on day 3 of each treatment. The half gastric emptying time (GET1/2) was determined by using ultrasonography to measure the decrease in the gastric antral cross sectional area after a feed. The whole gastrointestinal transit time (WGTT) was assessed by timing the transit of carmine red through the gut. Treatments were compared using the Wilcoxon matched pairs signed ranks test.

RESULTS

Median (range) birthweight was 1200 (620, 1450) g and postconceptional age 33 (29, 34) weeks at recruitment. GET1/2 was significantly longer during cisapride treatment than during placebo; the median of the differences (95% confidence interval) was 19.2 (11, 30 minutes, p=0.008). WGTT was also longer during cisapride treatment, but the difference was not significant; the median of the differences was 11(-18, 52 hours, p=0.1).

CONCLUSIONS

Cisapride delays gastric emptying and may delay WGTT in preterm infants. Its use to promote gastrointestinal motility in this group cannot be recommended.

Prokinetic agents for the treatment of postoperative ileus in adults: a review of the literature

Metoclopramide, cisapride, and erythromycin are commonly administered to reduce the duration of postoperative ileus (POI). As these agents are not without potential adverse effects, their efficacy in shortening the duration of POI should be evaluated. The etiology of POI is not well understood and therefore the precise treatment is unclear. Nasogastric suction is the mainstay of therapy, and management of fluid and electrolyte imbalances is crucial. The role of prokinetic agents is less understood. Available literature evaluating these drugs specifically for POI were reviewed, but results are confounded by issues such as sample size, variability in types of operations performed, and insensitive end points (flatus, bowel sounds). No literature supports reducing the duration of POI with metoclopramide, and limited data show benefit with cisapride. Data evaluating erythromycin are sparse, and the drug is believed to be ineffective. Domperidone, a prokinetic agent not available in the United States, has not been evaluated in POI. Due to these limitations, treatment remains largely supportive with a limited role for prokinetic agents.

Effect of cisapride on secondary peristalsis in patients with gastroesophageal reflux disease

OBJECTIVE

Improvement of esophageal acid clearance appears to be an important effect of cisapride in the treatment of reflux disease. The mechanism underlying this effect is not clear. Esophageal peristalsis is a major component of the acid clearance process. In normal subjects secondary peristalsis is an important mechanism of esophageal acid clearance during sleep, and this response appears to be impaired in patients with reflux esophagitis. The effects of cisapride on secondary peristalsis are not known. The aim of this study was to investigate the effects of cisapride on the triggering and characteristics of secondary peristalsis in patients with reflux esophagitis.

METHODS

In 17 patients with reflux esophagitis and impaired secondary peristalsis cisapride, 10 mg q.i.d., or placebo were administered in a randomized double blind, crossover design for 4 days separated by a 4-7 day washout period. On the fourth day of treatment, primary peristalsis and secondary peristalsis in response to 10- and 20-ml air boluses were assessed.

RESULTS

Secondary peristaltic success and amplitude were greater with the 20-ml bolus than with the 10-ml bolus. However, cisapride had no effect on either secondary peristaltic success or amplitude. Cisapride also had no effect on primary peristalsis or basal LES pressure.

CONCLUSIONS

The improvement in esophageal acid clearance by cisapride is not explainable by improvement in secondary peristalsis.

Torsade de pointes induced by cisapride/clarithromycin interaction

OBJECTIVE

To highlight a case of torsade de pointes ventricular arrhythmia induced by the concomitant use of cisapride and clarithromycin.

CASE SUMMARY

A 77-year-old white woman was admitted to the hospital with a diagnosis of pneumonia and exacerbation of congestive heart failure. In addition to her usual medications, which included cisapride, the patient was prescribed trimethoprim/sulfamethoxazole and clarithromycin for pneumonia. Within 48 hours, the patient had documented episodes of symptomatic torsade de pointes arrhythmia, which eventually responded to therapy. Both cisapride and clarithromycin were discontinued, and the patient did not have any recurring episodes during a 32-month follow-up.

DISCUSSION

Cisapride has been implicated in causing adverse cardiac events, including torsade de pointes arrhythmia. In most cases, the patients had preexisting risk factors for torsade de pointes and/or were receiving other medications known to inhibit the hepatic CYP3A4 enzyme system and the metabolism of cisapride. There is evidence that clarithromycin, a relatively new macrolide antibiotic, also inhibits the isoenzyme CYP3A4. The resulting accumulation of cisapride caused by concomitant clarithromycin therapy was believed to have been the cause of the torsade de pointes arrhythmia in this patient.

CONCLUSIONS

Concomitant use of cisapride and clarithromycin may cause torsade de pointes arrhythmia.

Pharmacokinetics of cisapride in the horse

The purpose of this study was to determine the pharmacokinetics and absolute bioavailability of cisapride after intravenous (i.v.) and intragastric (i.g.) administration in healthy, adult horses. Five animals received single doses of 0.1 mg/kg, 0.2 mg/kg and 0.4 mg/kg cisapride by the i.g. route in an open, randomized fashion on different occasions separated by a washout period of at least 48 h. Four of these horses were also given a single i.v. dose of 0.1 mg/kg cisapride. Jugular venous blood was collected periodically up to 24 h after dosing. Plasma cisapride concentrations were measured by high-performance liquid chromatography. There was considerable inter individual variability in pharmacokinetic parameters. The mean (SD) values for systemic clearance (CI) and steady-state volume of distribution (Vss) were 494 (43.6) mL/h/kg and 1471 (578) mL/kg, respectively. Although the rate of cisapride absorption was quite rapid, only about half the i.g. dose was absorbed systemically. The average terminal half-life (t1/2) calculated over three i.g. doses was 2.06 h and that for i.v. administration was 2.12 h. The pharmacokinetics of cisapride from 0.1 mg/kg to 0.4 mg/kg were independent of the i.g. dose.

Effects of cisapride on QT interval in children

Recent reports of torsade de pointes and heart block associated with prolonged QT interval in children receiving cisapride raise questions about its safety. We prospectively examined the effects of cisapride on the QT interval in children. Electrocardiography was performed on 30 children before and after cisapride was administered. An additional 71 children underwent electrocardiography only after starting cisapride. The incidence of a corrected QT (QTc) interval > 440 msec or a marked abnormality in T wave morphology was determined in all 101 children. Cisapride significantly lengthened the QTc with a mean increase of 15.5 +/- 4.6 msec (mean +/- SEM, p = 0.002 in the 30 children with baseline electrocardiographs. Twelve of the 101 patients were found to have a QTc > 440 msec, and one had a new prominent notched T wave in all leads. In these 13 (13%) patients with repolarization abnormalities, other factors that might contribute to a long QT were noted in 11 (85%) patients. We conclude that cisapride use in children is associated with a modest increase in QT interval. The incidence of QTc > 440 msec is low. Most children with long QTc have other factors that could compound the effects of cisapride.

Gastroesophageal reflux in children

Gastroesophageal reflux (GER) is a common disorder in infants and children with a high rate of spontaneous resolution. Some children, however, will continue to have problems and progress from functional GER to pathogenic GER. In children with functional GER, diagnostic testing and pharmacologic treatment is unnecessary. In more involved cases, there are a number of tests available that help to quantify and qualify the extent of disease. Treatment begins with conservative measures and progresses to acid neutralization/supression and medications to enhance motility. Should medical management fail to control the consequences of reflux disease, surgical intervention is warranted.

Pharmacokinetic profile of cisapride 20 mg after once- and twice-daily dosing

Cisapride is a substituted piperidinyl benzamide. It is chemically related to metoclopramide but lacks the antidopaminergic properties of metoclopramide that affect the central nervous system and cause extrapyramidal side effects. Cisapride is indicated for the symptomatic treatment of patients with nocturnal heartburn due to gastroesophageal reflux disease. Based on extensive assessment of the drug's pharmacokinetic profile, the currently approved initial oral dosing regimen for cisapride is 10 mg QID. However, the pharmacokinetics of cisapride after oral administration of 20 mg BID have not been investigated. We present here findings from an open-label trial assessing the pharmacokinetics of cisapride 20-mg tablets after a single dose and at steady state (BID dosing). The results indicate that 20-mg BID and 10-mg QID regimens produce similar steady-state concentrations.

Management and causes of acute large-bowel obstruction

Acute LBO has many possible causes. In the United States, the most common cause is colorectal carcinoma. Mechanical obstruction should be differentiated from pseudo-obstruction by contrast enema or colonoscopy because the treatments differ. The high postoperative mortality and morbidity of LBO compared with elective resection are explained by the multiple associated pathophysiologic changes of obstruction. Management of this condition requires careful assessment, awareness, and expertise in the current modalities of treatment. Gangrene and perforation should be avoided because they limit treatment options and are associated with an increase in mortality. We prefer, in most instances, to perform a single-stage procedure, which has the advantages of reduced hospital stay (and cost) and avoidance of a stoma. However, the appropriate treatment needs to be tailored to the individual situation. Recent developments in nonoperative decompressing procedures may demonstrate advantages in the future.

Ecabapide, a novel gastroprokinetic agent, ameliorates gastric emptying of stroke-prone spontaneously hypertensive rats (SHRSP)

The effect of ecabapide, a novel gastroprokinetic agent, on gastric emptying was examined in stroke-prone spontaneously hypertensive rats (SHRSP), which are known to exhibit gastric malfunctions as a result of autonomic nervous system disorder. Ecabapide was administered orally to SHRSP in various dose-regimens. Gastric emptying was evaluated by the acetaminophen (APAP) method using semi-solid meal under the conscious conditions. Ecabapide significantly enhanced gastric emptying of SHRSP at 1 mg/kg in single administration, 0.3 and 1 mg/kg in 2-week treatment and 7.7 mg/kg in 4-week (diet) exposure. These results suggest that the effect of ecabapide is exerted without showing tachyphylaxis.

Pharmacology of the gastric pro-kinetic drug ecabapide (DQ-2511)

The pharmacology of ecabapide (DQ-2511; 3-[2-(3,4-dimethoxyphenyl)ethylcarbamoylmethyl]amino-N-methylbe nzamide) is reviewed. Evidence from basic studies in animal models suggests that the drug acts on peripheral mechanisms of neural control. In the stomach, ecabapide acts to suppress firing in vagal afferent nerves and thereby reduce the flow of sensory information into the dorsal vagal complex. The enhancement of the efferent discharge provoked by ecabapide was completely blocked by bilateral vagotomy, as suggested by increased firing in vagal efferent fibres, preceded by suppression of activity in the sensory limb of the putative vago-vagal reflex pathway. The mechanism of action of ecabapide in suppressing discharge in vagal afferent terminals appears to mimic that of nitric oxide by stimulating formation of cGMP and activation of an inhibitory transduction cascade in the sensory fibres. In this respect the mechanism of its pro-kinetic action differs from other promoter agents. In addition to selective actions in the stomach, evidence from electrophysiological studies of enteric neurons in the small intestine suggests that ecabapide might have actions similar to those of other substituted benzamides on synaptic transmission in the intramural nervous system of this specialized region of the digestive tract. These actions include enhanced release of acetylcholine at excitatory synapses and suppression of the release of noradrenaline at inhibitory synapses.

Cisapride use during human pregnancy: a prospective, controlled multicenter study

The objective of this prospective multicenter study was to determine whether cisapride is associated with increased risk of malformations, spontaneous abortions, or decreased birthweight when used during pregnancy. Cases were paired for age, smoking, and alcohol consumption with controls exposed to nonteratogens, as well as with disease-paired controls. One hundred and twenty-nine pregnant women were exposed to cisapride during pregnancy, including 88 during the period of fetal organogenesis. There were no differences in maternal history, birthweight, gestational age at delivery, and rates of livebirths, spontaneous or therapeutic abortions, fetal distress, and major or minor malformations among groups. It is concluded that exposure to cisapride during pregnancy is not associated with a major increased risk of malformations or spontaneous abortions or with decreased birthweight.

Effect of megestrol acetate and prepulsid on nutritional improvement in patients with head and neck cancers undergoing radiotherapy

BACKGROUND AND PURPOSE

Anorexia is a common problem in cancer patients who receive radiotherapy. In this current study, we attempt to determine the effect of megestrol acetate and prepulsid on appetite and nutritional improvement in patients with head and neck cancers undergoing radiotherapy.

MATERIALS AND METHODS

One hundred twenty-nine consecutive patients with head and neck cancers treated between July 1993 and June 1994 were prospectively randomized to receive either megestrol acetate, 40 mg qid (megace group), prepulsid, 5 mg tid (cisapride group), or a placebo treatment (control group) during radiotherapy. Before radiotherapy, body weight (kg), appetite score, performance status, biochemical parameters and hematological parameters were evaluated, and the above-noted clinical and biochemical parameters were assessed and recorded every other week. All patients received 6- 10 MV X-rays or Co-60 gamma-ray to head and neck region for a full course of radiotherapy, 61.2-75.6 Gy/7-9 weeks.

RESULTS

Forty-eight patients were enrolled in the megace group, 41 patients in the cisapride group, and 40 patients in the control group. At the 2nd, 4th, 6th and 8th week, as the radiation dose escalated, the megace group had significantly less body weight loss than did the cisapride and control groups (P = 0.045, 0.024, 0.006, 0.003, respectively). The appetite scores of the megace group were significantly higher than those of the cisapride and control groups (P = 0.0001). However, there were no statistically significant differences in the change of albumin level among these three groups at the 2nd, 4th, 6th and 8th week (P > 0.05, respectively).

CONCLUSIONS

Megestrol acetate can significantly decrease the degree of body weight loss, and can prevent the deterioration of appetite in patients with head and neck cancers receiving radiotherapy. However, prepulsid lacks the above-mentioned clinical benefits.

Double-blind, randomized study of the effect of cisapride on gastric emptying in critically ill patients

OBJECTIVES

To investigate the absorption of the gastrokinetic drug, cisapride, and effect of cisapride on gastric emptying in critically ill patients; and to assess the usefulness of clinical signs of gastric emptying.

DESIGN

Prospective, randomized, controlled study.

SETTING

Medical/surgical/trauma intensive care unit (ICU) in a university hospital.

PATIENTS

Twenty-seven consecutively enrolled patients, aged 18 to 65 yrs, with normal hepatic and renal biochemistry who were not receiving enteral nutrition and who had no contraindications to enteral nutrition. These patients were expected to stay in the ICU for at least 4 days.

INTERVENTIONS

Patients were randomized to receive either placebo or rectal cisapride, 60 mg initially followed by two doses of 30 mg at 8-hr intervals.

MEASUREMENTS AND MAIN RESULTS

Gastric emptying was estimated, using acetaminophen absorption on day 1 of the study. Placebo or cisapride was administered and a second acetaminophen absorption test for gastric emptying was carried out on day 2,24 hrs after the first test. Four patients were excluded because of incomplete data. Statistical analysis was performed, using the area under the acetaminophen absorption curve from 0 to 60 mins as the primary measure of gastric emptying. There was no significant change in the area under the acetaminophen absorption curve from 0 to 60 mins from day 1 to day 2 in patients who received placebo or cisapride. Using the combination of the time to maximum acetaminophen concentration (< or = 30 mins) with a maximum concentration (> 12 mg/L) to define "normal" emptying, on day 1, four of the 11 placebo patients had the "normal" gastric emptying, and by day 2, five patients fulfilled this criterion. Before administration of cisapride, four of the 12 patients fulfilled this criterion, whereas nine fulfilled the criterion after receiving cisapride. There was a large variation in gastric emptying from day 1 to day 2; a power calculation suggests that approximately 150 patients would have to be studied to determine the effect of cisapride. There was no correlation between gastric emptying and the volume of gastric aspirate or the presence of bowel sounds. Plasma cisapride concentrations 4 hrs after the third dose, during the second acetaminophen absorption test, averaged 53 ng/mL (range 20 to 111).

CONCLUSIONS

Rectal cisapride in the dose given achieved average plasma concentrations similar to those concentrations achieved in healthy subjects after 30 mg of cisapride rectally. There is a large variation in gastric emptying from one day to the next and large numbers of patients are required to determine if cisapride administration improves early gastric emptying in critically ill patients. The volume of gastric aspirate and the presence of bowel sounds do not correlate with gastric emptying.

Comparative evaluation of DQ-2511, a novel gastroprokinetic agent, with cisapride in ameliorative action on experimentally induced delayed gastric emptying

We compared the main pharmacological effect of DQ-2511 (3-[[[2-(3,4-dimethoxyphenyl)- ethyl]carbamoyl]methyl]amino-N-methylbenzamide), a novel gastroprokinetic agent, with that of cisapride. Single oral administration of DQ-2511 (3-10 mg kg-1) caused similar significant improvements to delays in gastric emptying of semi-solid meals evoked by cholecystokinin-octapeptide (CCK8: 5 micrograms kg-1, i.v.) in monkeys, to that with cisapride (3 mg kg-1). A 2-week oral treatment of unilaterally vagotomized rats with DQ-2511 (1-10 mg kg-1) lessened delays in gastric emptying, whereas cisapride (0.3-10 mg kg-1) had no effect under the same experimental protocols. In anesthetized rats, bolus intravenous injection of either compound (60 micrograms kg-1) enhanced gastric motility determined by means of strain gauge force transducers. Electrophysiological investigations revealed that bolus injection of DQ-2511 (6-60 micrograms kg-1) depressed the afferent discharge rate of the ventral gastric branch of the vagus nerve, while cisapride showed no effect. These results suggest that the mechanism of ameliorative action of DQ-2511 on delayed gastric emptying may differ from that of cisapride.

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.

Gastroesophageal reflux. Diagnostic and therapeutic approaches

The clinical challenge of determining the medical conditions that are associated with obvious symptoms of gastroesophageal reflux and what diagnostic tests are appropriate to define this relationship is substantial. To determine which infants may be suffering from pathologic conditions associated with subtle signs of gastroesophageal reflux is even more challenging. This determination is essential to avoid subjecting many healthy infants to costly and potentially invasive testing. This article focuses on the physiology, clinical presentations, diagnosis and evaluation, and therapy of gastroesophageal reflux.

The effects of 4 weeks treatment with cisapride on cystometric parameters in spinal cord injury patients. A double-blind, placebo controlled study

A group of 21 complete spinal cord injury patients, beyond the phase of spinal shock, were given a treatment of cisapride at random, 10 mg four times a day for 4 weeks. Cystometry was performed first before the start and during the following 4 weeks. No statistically significant difference could be found in the urodynamic parameters between the two groups at the first cystometry. No statistically significant change of the urodynamic parameters could be demonstrated with the treatment, although a non-statistically significant bladder stimulating effect was present in a majority of the patients in the cisapride group.

Analysis of cisapride in neonatal plasma using high-performance liquid chromatography with a base-stable column and fluorescence detection

A simple, selective, sensitive, and precise high-performance liquid chromatographic plasma assay for the prokinetic drug cisapride is described. Alkalinised samples of plasma (100 microliters) were extracted with 1.0 ml of 10% (v/v) isopropanol in chloroform, dried, redissolved in mobile phase and injected. Chromatography was performed at 20 degrees C by pumping a mobile phase of acetonitrile (370 ml) in pH 5.2, 0.02 M phosphate buffer (630 ml) at 1.0 ml/min through a C8 Symmetry column. Cisapride and the internal standard were detected by fluorescence monitoring at 295 nm (excitation) and 350 nm (emission), and were eluted 5 min and 8 min, respectively, after injection. Calibration plots in bovine serum albumin (3% w/v) were linear (r > 0.999) from 5 to 250 ng/ml. Intra-day and inter-day precision (C.V.) was 9.5%, or less, and the accuracy was within 5.5% of the nominal concentration over the range 8-200 ng/ml. Total assay recovery was above 82%. Endogenous plasma components, the major cisapride metabolite (norcisapride), and other drugs used in neonatal pharmacotherapeutics did not interfere.

Treating constipation in the patient with diabetes

Patients with diabetes have a significant risk of developing severe constipation often due to dysfunction of the autonomic nervous system. Constipation is a symptom, rather than a disease, and is characterized by decreased defecation frequency, increased stool hardness, and/or difficulty passing fecal matter. Self-treatment of constipation with over-the-counter laxative products, home remedies, and foodstuffs is commonplace. Patients frequently call upon health professionals for advice regarding constipation. The diabetes educator should be familiar with the causes and rational treatment of this disorder in the person with diabetes.