Cisapride. An updated review of its pharmacology and therapeutic efficacy as a prokinetic agent in gastrointestinal motility disorders

Comparison of tegaserod (HTF 919) and its main human metabolite with cisapride and erythromycin on cardiac repolarization in the isolated rabbit heart

Tegaserod (HTF 919) is a new drug being developed for gastrointestinal motility disorders. Because other gastrointestinal prokinetic agents, such as cisapride and erythromycin, cause slowing of cardiac repolarization and have been implicated in the development of the potentially fatal ventricular arrhythmia, torsades de pointes, a study was initiated to determine whether tegaserod and its main human metabolite adversely influence cardiac repolarization. By using isolated Langendorff-perfused rabbit hearts, we show that QT intervals remain unchanged at concentrations of tegaserod from 0.5 to 10 microM. It was not until the tegaserod concentration was increased to 50 microM (roughly 500-5,000 times more concentrated than those typically found in human plasma after administration of recommended clinical dosages), that a small, but significant increase in the QT interval (12+/-4%; p < 0.05; n = 4) was observed. No significant changes in QT occurred in the presence of the tegaserod metabolite at any of the concentrations tested (0.5-50 microM). In contrast, cisapride caused QT lengthening at concentrations as low as 0.1 microM, with significant QT increases occurring when 5-50 microM cisapride was used (22+/-4% to >70%, respectively; p < 0.01; n = 4). Erythromycin also caused significant lengthening of QT intervals (11+/-2%; p < 0.001; n = 4), although 100 microM concentrations of this drug were required to achieve this effect. These results demonstrate that both cisapride and erythromycin can slow cardiac repolarization at therapeutic doses and that tegaserod's lack of QT prolongation at therapeutic doses suggests that it has the potential to be a safer alternative to cisapride as a gastrointestinal prokinetic agent.

Diabetic gastropathy: gastric neuromuscular dysfunction in diabetes mellitus: a review of symptoms, pathophysiology, and treatment

Diabetic gastropathy is a term that encompasses a number of neuromuscular dysfunctions of the stomach, including abnormalities of gastric contractility, tone, and myoelectrical activity in patients with diabetes. These abnormalities range from tachygastrias to antral hypomotility and frank gastroparesis. Diabetic gastropathies may be acutely produced during hyperglycemia. Symptoms of chronic diabetic gastropathy include chronic nausea, vague epigastric discomfort, postprandial fullness, early satiety, and vomiting. Because these symptoms are nonspecific, other disorders such as mechanical obstruction of the gastrointestinal tract, gastroesophageal reflux disease, cholecystitis, pancreatitis, mesenteric ischemia, and drug effects should be considered. Neuromuscular abnormalities of the stomach may be assessed noninvasively with gastric emptying tests, electrogastrography, and ultrasound. Gastrokinetic agents such as metoclopramide, cisapride, domperidone, and erythromycin increase fundic or antral contractions and/or eradicate gastric dysrhythmias. Diet and glucose control also are important in the management of diabetic gastropathy. As the pathophysiology of diabetic gastropathy is better understood, more specific and improved treatments will evolve.

A prospective, randomized, double-blinded, placebo-controlled trial of cisapride after colorectal surgery

BACKGROUND

The predominant factor prolonging hospitalization and delaying oral intake after colorectal surgery continues to be return of large bowel function. We investigated the effect of the cisapride on postoperative bowel motility.

METHODS

Patients were started on cisapride versus a placebo on postoperative day 1 after colorectal surgery. Endpoints included the time to patients' first bowel movement, time of advancement to regular diet, time of hospitalization, and cost analysis. Results were analyzed using a Mann-Whitney test.

RESULTS

Thirty-five patients were entered in the study, consisting of 17 in the cisapride group and 18 in the placebo group. The median time to first bowel movement, advancement of diet, and hospital discharge was 1 day less in the cisapride group compared with the placebo group (P <0.05). There was a substantial cost savings in the study group.

CONCLUSIONS

Cisapride use results in statistically significant improvement in postoperative bowel motility. Cisapride should be added as adjunct treatment in postoperative care after colorectal surgery.

The effect of cisapride on duodenal acid exposure in the proximal duodenum in healthy subjects

AIM

To investigate the effect of the prokinetic drug, cisapride, on fasting and postprandial acid exposure in the proximal duodenum.

METHODS

Using a double-blind, placebo-controlled crossover study design, 12 healthy male volunteers were studied. After 1 week of dosing (cisapride 20 mg b.d. orally or placebo), fasting and postprandial antroduodenal pH-and pressure-recordings were made. Using a small-caliber (4 mm) catheter, containing one antral and two duodenal pH electrodes, and two antral and three duodenal pressure recording sites. Transmucosal potential difference was measured to ensure proper catheter position. Infusions of 0.1 N HCl were given in the duodenal bulb.

RESULTS

Endogenous acidification of the duodenal bulb occurred more frequently during phase II and postprandially, compared to phase I (P<0.001). During phase I, alkalinization of the antrum was observed. Cisapride significantly increased the postprandial number of duodenal acidic periods (P<0.02), but shortened their duration (P<0.04). The duodenal motor response elicited by exogenous acid was lower during phase I (P<0.05).

CONCLUSIONS

Antral and proximal duodenal acidity vary with the phases of the interdigestive motor complex. Cisapride shortens the individual periods of duodenal acidification.

Macrophage Fcgamma receptors expression is altered by treatment with dopaminergic drugs

Macrophage Fcgamma receptors have an important role in host defense and the pathophysiology of immune mediated disorders. Alteration of splenic macrophage Fcgamma receptors expression predisposes to severe infection. Inhibition or blockade of splenic macrophage Fcgamma receptors is one of the mechanisms by which immune cytopenias improve. Dopaminergic drugs have clinically significant regulatory functions on the immune response. Using an experimental model in the guinea pig we assessed the effect of commonly used dopaminergic drugs on the expression of macrophage Fcgamma receptors. Three dopa-antagonists, bromocryptine, leuprolide, and pergolide, and seven dopa-antagonists, chlorpromazine, SCH 23390, metochlopramide, sulpiride, veralipride, alizapride, and cisapride, were studied. Following guinea pig treatment with dopaminergic drugs, the clearance of IgG-sensitized RBCs in vivo, the in vitro binding of IgG-sensitized RBCs by isolated splenic macrophages and flow cytometry with monoclonal antibodies were performed. Treatment with dopa-agonists enhanced the clearance of IgG-sensitized RBCs, the in vitro binding of IgG-sensitized RBCs by isolated splenic macrophages, and the cell surface expression of both macrophage Fcgamma receptors, and vice versa, dopa-antagonists impaired macrophage Fcgamma receptors expression. Macrophage FcgammaR1,2 was more sensitive than FcgammaR2 to such dopaminergic effect. These alterations of macrophage Fcgamma receptors expression are mediated by both D1 and D2 dopamine receptors, with a major participation of D2 receptors. Dopaminergic drugs alter the clearance of IgG-coated cells by an effect at the expression of splenic macrophage Fcgamma receptors.

Efficacy of prolonged administration of intravenous erythromycin in an ambulatory setting as treatment of severe gastroparesis: one center's experience

Intravenous erythromycin is a potent gastric prokinetic with demonstrated efficacy in the acute therapy of gastroparesis; long-term oral therapy has been limited by tolerance and modest efficacy. Our aim was to review our experience with prolonged administration of intravenous erythromycin in an ambulatory setting as therapy for severe gastroparesis, refractory to usual dietary and oral prokinetic regimens. We conducted a retrospective analysis of patients with gastroparesis treated with intravenous erythromycin for at least 1 month. Information on demographics; origin of gastroparesis; dosage, duration, and route of administration; clinical outcome in the short- and longer-term; and complications were determined. Eleven patients received a total of 14 courses of intravenous erythromycin for a median of 6.5 months (range, 1 to 19 months) at a median dosage of 300 mg/day (range, 150 to 1,000 mg/day). One patient received no benefit, two had complete responses, and all others reported some benefit. Two had dramatic relapse on cessation of therapy and subsequently improved on its resumption. Parenteral nutrition could be discontinued in one of four patients. There were four episodes of line sepsis; two required catheter removal. A nonocclusive thrombus developed at the site of a central line in one patient. Secondary infections or antibiotic resistance were not encountered. Prolonged administration of intravenous erythromycin in an ambulatory setting is feasible, well tolerated, and effective in patients with severe gastroparesis.

Cisapride in management of chronic pediatric constipation

BACKGROUND

This study was conducted to explore the use of cisapride in the treatment of chronic idiopathic constipation in children.

METHODS

Seventy-nine children were screened. Seventy-three of them met the selection criteria that included clinical, laboratory, radiologic, and histopathologic investigations. These patients entered a week-long phase I of disimpaction using lactulose. Four of them were noncompliant and thus were excluded from the next phase. In phase II sixty-nine patients were assigned to two treatment groups: 0.3 mg/kg cisapride four times a day versus matching placebo for 8 weeks in a double-blind study. The two groups that completed phase II were similar in age and duration of symptoms, confirmed by statistical analysis. Stool frequency was assessed weekly, beginning at the end of the disimpaction phase and continuing for 9 weeks. Total gastrointestinal transit time was measured twice, on completion of phase I and 9 weeks later. Transit time is the time required for a carmine marker taken orally after overnight fast to appear in the stool.

RESULTS

There was a significant difference between stool frequency per week before and after cisapride treatment, stool frequency per week at the end of phase II with cisapride versus placebo, and total gastrointestinal transit time before and after treatment with cisapride (p < 0.05 for all values). No such difference was demonstrated when comparing stool frequency per week or total gastrointestinal transit time before and after placebo (p > 0.05 for both).

CONCLUSIONS

Cisapride may have a role in the management of chronic idiopathic constipation in children.

Cisapride: a survey of the frequency of use and adverse events in premature newborns

OBJECTIVE

This survey estimated the frequency of use and adverse events associated with cisapride treatment of premature newborns in intensive care units. It was initiated in response to a warning issued in Canada cautioning against cisapride treatment of premature infants of <36 weeks' gestation and <3 months of age.

METHODOLOGY

Surveys were mailed to 105 neonatology training program directors to obtain the total number of neonatal intensive care unit (NICU) admissions, the number of admissions of infants of <36 weeks' gestation, the number of years that cisapride had been used, the estimated percent/number of premature patients treated with cisapride per year, and the frequency and nature of arrhythmias or other adverse events associated with cisapride treatment. Of 105 programs, 46 responded to a single mailing of the first survey. A second survey mailed to the 45 respondents to the first survey sought to determine the indications, diagnostic tests, and dosages used with cisapride treatment of premature newborns. Of the 45 programs, 26 responded to the second survey.

RESULTS

More than 58 000 premature newborns of <36 weeks' gestation were admitted to the NICUs we surveyed, and approximately 19% were treated with cisapride. No deaths attributable to cisapride were reported among >11 000 preterm newborns treated. Three nonfatal arrhythmias were reported; two associated with 10-fold dosing errors and one with co-treatment with erythromycin, a macrolide antibiotic that reduces the metabolism of cisapride. Diarrhea was reported in 12 patients, and reversible liver enzyme changes were noted in one patient. Typically, cisapride treatment was started in dosages of 0.1 to 0.2 mg/kg/dose, repeated every 6 to 8 hours. Treatment usually was begun empirically, without a preceding study to document gastroesophageal reflux. The most frequent indications for cisapride treatment were choking or gagging, with associated apnea, bradycardia, and desaturation. Approximately 50% of patients had discontinued cisapride treatment before discharge. Eighty-four percent of clinicians judged cisapride to be effective for the problems being treated.

CONCLUSIONS

Cisapride treatment of premature infants of <36 weeks' gestation and <3 months of age in NICUs appears to be widespread in the United States. Complications and adverse events were seen when cisapride was administered in excessive dosages or in combination with a drug that inhibits its metabolism and leads to increased serum concentrations. Severe toxicities such as arrhythmias were reported with a frequency of <1/11 000 NICU admissions. However, in a retrospective survey, episodes of toxicity, including mortality, attributable to cisapride may not have been recognized or reported.

Diabetic and Nondiabetic Gastroparesis

Nutritional support is essential in treating patients with gastroparesis. Initially, dietary changes should be instituted to reduce extra fat and bulk, and patients should be encouraged to eat frequent small meals with liquid supplementation. Enteral feeding should be introduced in the event of weight loss or persistent vomiting. Medical therapy is usually necessary early in treatment. Cisapride is the initial agent of choice and may be combined with an antiemetic agent, such as promethazine or chlorpromazine or, if side effects occur, ondansetron and granesitron. If cisapride is ineffective or contraindicated, metoclopramide is a reasonable option, though limited by side effects. Erythromycin is useful in the acute treatment of postoperative ileus and hospitalized gastroparetic patients, but its role is limited based on concerns about poor long-term effectiveness and antimicrobial resistance. Once domperidone becomes available in the United States, it will be useful for its promotility and antiemetic qualities. Combination therapy should be considered if monotherapy with cisapride or metoclopramide alone is ineffective. While not yet well studied, combination therapy has the potential to offer dramatic benefit for patients with refractory gastroparesis. Metoclopramide may be added to cisapride for patients with breakthrough symptoms or refractory chronic symptoms. Other combinations include metoclopramide with erythromycin, domperidone with cisapride, and domperidone with erythromycin. In the future, gastric pacing may become an effective option for patients not responding to medical therapy. Total gastrectomy should be performed only for end-stage gastroparesis when all other therapy has failed. Both procedures should be reserved for centers that specialize in severe gastric motility disorders.

Functional gut disorders: from motility to sensitivity disorders. A review of current and investigational drugs for their management

Functional gut disorders include several clinical entities defined on the basis of symptom patterns (e.g., functional dyspepsia, irritable bowel syndrome, functional abdominal pain, functional abdominal bloating), for which there is no established pathophysiological mechanism. Because there is no well-defined pathophysiological target, treatment should be aimed at symptom improvement. Prokinetics and antispasmodics have been widely used in the treatment of functional gut disorders on the assumption that disordered motility is the underlying cause of symptoms, and symptom improvement is indeed achievable with these compounds in some, but not all, patients with features of hypo- or hypermotility, respectively. In the first part of this review, we cover the basic pharmacology and discuss the rationale for the clinical use of prokinetics and antispasmodics. On the other hand, in the past few years, the explosive growth in the research focusing on visceral sensitivity and visceral reflexes has suggested that at least some patients with functional gut disorders have altered visceral perception. Thus, the second part of the review covers these developments and focuses on studies addressing the issue of drugs modulating visceral sensitivity.

Determination of cisapride and norcisapride in human plasma using high-performance liquid chromatography with ultraviolet detection

A simple, rapid and reproducible high-performance liquid chromatographic assay for cisapride and norcisapride in human plasma is described. Samples of plasma (150 microl) were extracted using a C18 solid-phase cartridge. Regenerated tubes were eluted with 1.0 ml of methanol, dried, redissolved in 150 microl of methanol and injected. Chromatography was performed at room temperature by pumping acetonitrile-methanol-0.015 M phosphate buffer pH 2.2-2.3 (680:194:126, v/v/v) at 0.8 ml/min through a C18 reversed-phase column. Cisapride, norcisapride and internal standard were detected by absorbance at 276 nm and were eluted at 4.3, 5.3 and 8.1 min, respectively. Calibration plots in plasma were linear (r>0.998) from 10 to 150 ng/ml. Intraday precisions for cisapride and norcisapride were 3.3% and 5.4%, respectively. Interday precisions for cisapride and norcisapride were 9.6% and 9.0%, respectively. Drugs used which might be coadministered were tested for interference.

Effects of gastrointestinal prokinetic agents, TKS159 and cisapride, on the in situ canine heart assessed by cardiohemodynamic and electrophysiological monitoring

Effects of a novel 5-HT4 receptor agonist TKS159 on the cardiovascular system were assessed in comparison with cisapride using an in vivo canine model. TKS159 in doses of 0.1, 1.0, and 10 mg/kg (n = 6) or cisapride in 1/10 doses of 0.01, 0.1, and 1.0 mg/kg (n = 6) was cumulatively infused over 10 min with a pause of 20 min. The doses of the drugs were determined according to the previous knowledge of their pharmacokinetics. Clinically effective plasma concentrations as a gastrointestinal prokinetic drug were obtained after the infusion of 0.1 mg/kg of the respective drugs. In TKS159-administered animals, no significant change was induced in each cardiovascular parameter by an infusion of 0.1 mg/kg. The blood pressure was decreased, and the effective refractory period and repolarization phase of the ventricle were prolonged after 1.0 mg/kg. The heart rate was decreased, and the atrioventricular, as well as intraventricular, conduction were suppressed after 10 mg/kg, while no significant changes were observed in the cardiac output and the ventricular contraction and the relative refractory period of the ventricle during the study. Meanwhile, in cisapride-administered animals, the repolarization phase and the effective refractory period were prolonged after 0.01 mg/kg. The heart rate and the blood pressure were decreased after 0.1 mg/kg. The cardiac output, the ventricular contraction, and the atrioventricular conduction were suppressed, the relative refractory period was prolonged, and early afterdepolarization was detected after 1.0 mg/kg, while no significant change was observed in the intraventricular conduction during the study. Thus, TKS159 may have a safer cardiovascular profile than cisapride.

Randomised controlled trial of cisapride in feed intolerance in preterm infants

AIM

To assess the efficacy of cisapride in reducing the time required to establish enteral feeds in preterm infants.

METHODS

A randomised, double blind, placebo controlled trial was conducted of 34 infants of < or = 32 weeks of gestation, assigned to receive either cisapride 0.2 mg/kg/dose four times daily (n = 18) or placebo (n = 16).

RESULTS

The time taken by the babies to tolerate full enteral feeds was not significantly different between the groups (median 9.5 days vs 10 days). There was a significantly lower incidence of large gastric residuals and regurgitation in the treated group compared with the placebo group. The number of episodes of large gastric residuals per infant was also significantly less. No adverse effects were noted.

CONCLUSION

The routine use of cisapride in preterm infants cannot be recommended to decrease the time to establish enteral feeds. Its use may be justified for clinically significant gastric stasis or regurgitation.

Effect of cisapride on gastric emptying in horses following endotoxin treatment

The effect of cisapride pretreatment on gastric emptying in horses was determined by measuring serum concentrations of acetaminophen, a drug known to be readily absorbed in the small intestine but not in the stomach. The time to reach maximum serum acetaminophen concentrations (Tmax), the maximum serum concentrations (Cmax) and the area under the serum acetaminophen concentration vs. time curves (AUC) were compared among treatment groups. In the first part of the study, the effect of orally administered cisapride (0.1, 0.2 and 0.4 mg/kg bwt) on gastric emptying was examined in 6 normal fasted horses. In the second part of the study, gastric emptying in horses given endotoxin i.v. (n = 6) was compared to those that received cisapride per os prior to administration of endotoxin (n = 6) and those that received neither compound (n = 6). Cisapride did not alter gastric emptying in normal horses. Endotoxin caused a profound delay in gastric emptying and pretreatment with cisapride significantly attenuated this effect. It is concluded that cisapride may be useful as a prophylactic measure when administered prior to the development of endotoxaemia.

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.

Cisapride 20 mg b.i.d. provides symptomatic relief of heartburn and related symptoms of chronic mild to moderate gastroesophageal reflux disease. CIS-USA-52 Investigator Group

OBJECTIVE

We evaluated the efficacy and safety of a twice-daily dosage regimen of cisapride 20 mg in relieving the symptoms of mild-moderate gastroesophageal reflux disease (GERD) in patients with moderate intensity heartburn and no history of erosive esophagitis.

METHODS

After a 2-wk, single-blind, placebo run-in period, 398 patients who continued to experience moderate intensity heartburn were randomized to either placebo (n = 196) or cisapride 20 mg (n = 202) twice daily for 4 wk.

RESULTS

Compared with placebo, cisapride significantly reduced scores for daytime and nighttime heartburn (p < 0.001), total regurgitation (p < 0.001), eructation (p = 0.04), and early satiety (p = 0.04). Cisapride 20 mg b.i.d. was also superior to placebo in reducing total use of rescue antacid medication (p < 0.001); reducing, in concordance analyses, daytime and nighttime heartburn with antacid usage (p < 0.001); increasing the percentage of heartburn-free days and antacid-free nights (p < 0.5); and increasing the percentage of patients self-rated as having minimal or better symptomatic improvement (p = 0.01). Cisapride 20 mg b.i.d. was well tolerated. The most common adverse event in the cisapride group was diarrhea, reported by 10% of patients, compared with an incidence of 4% in the placebo group.

CONCLUSION

Cisapride 20 mg b.i.d. was shown to be effective and safe for the short-term treatment of daytime and nighttime heartburn and for other symptoms associated with mild-moderate GERD.

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.

Effect of mental stress and cisapride on autonomic nerve functions in functional dyspepsia

BACKGROUND

Disordered autonomic nerve function is frequently present in patients with functional dyspepsia (FD). In this study we investigated whether the prokinetic cisapride, which acts via acetylcholine receptors, and stress may modulate these abnormalities.

METHODS

Nineteen patients (6 men, 13 women) with FD and 10 healthy subjects (3 men, 7 women) were studied after 3 days' treatment with 10 mg cisapride three times daily and placebo in a crossover design. Mental stress was induced with a videogame. Sympathetic and vagal nerve functions were assessed noninvasively by skin conductance and respiratory sinus arrhythmia, respectively.

RESULTS

Vagal tone was significantly lower in FD patients than in controls both before and after mental stress (P < 0.001). Sympathetic tone was higher in patients with FD than in controls (P < 0.03). Generally, stress scores were increased by mental stress in both groups (P < 0.001). In FD patients, but not in controls, cisapride significantly increased the sympathetic tone both before (P < 0.05) and after stress (P < 0.05).

CONCLUSIONS

Patients with FD have lower vagal tone and higher sympathetic tone than healthy controls. Treatment with cisapride increased sympathetic tone in the patient group but had no effect on vagal tone.

The symptomatic effect of cisapride in patients with irritable bowel syndrome and constipation

BACKGROUND

Cisapride improves symptoms in patients with idiopathic constipation. This trial compares the effect of cisapride with that of placebo in patients with irritable bowel syndrome (IBS) and constipation.

METHODS

Seventy patients were randomized to 12 weeks' treatment with 5 mg cisapride three times daily or placebo in a double-blind trial. The dose could be doubled after 4 weeks in patients without satisfactory improvement. The patients scored their symptoms on a 100-mm visual analogue scale (VAS) (0 = best, 100 = worst), and the investigators evaluated the symptomatic effect.

RESULTS

The dose was doubled in 17 and 23 patients in the cisapride and placebo groups, respectively, after 4 weeks. The patients' mean VAS score for global evaluation of IBS symptoms in the cisapride and placebo groups was 73 and 71 mm, respectively, at the start of treatment and 47 and 41 mm at the end. The difference between cisapride and placebo at the end was 6 mm in favour of placebo (95% confidence interval (CI), -6, 18) (NS). The investigators evaluated the effect as good or excellent in 39.2% and 58.8% in the cisapride and placebo groups, respectively. The difference in favour of placebo was 19.5% (95% CI, -5, 44) (NS). Nor were any statistically significant differences seen between cisapride and placebo in the other effect factors.

CONCLUSIONS

The trial seems to exclude a clinically significant effect of 15-30 mg cisapride daily in patients with IBS and constipation during a 12-week treatment period.

The effect of cisapride on oral and intravenous glucose tolerance in normal subjects

Cisapride is used widely for the treatment of diabetic gastroparesis. There is some evidence that cisapride may influence insulin secretion. The aim of this study was to evaluate the effect of cisapride on plasma concentrations of glucose, insulin and C-peptide in response to oral and intravenous glucose loads. Twelve normal subjects took cisapride and placebo, each for 10 days using a randomized, double-blind, crossover design. In each treatment phase, the plasma glucose, insulin and C-peptide response to intravenous (0.5 g/kg) and oral (75 g) glucose loads was evaluated on separate days. Gastric emptying of the oral glucose load was also measured. After the intravenous glucose load, plasma concentrations of C-peptide were higher (P< 0.01) on cisapride when compared with placebo (e.g. peak C-peptide 2.08+/-0.25 nmol/L vs 1.78+/-0.22 nmol/L, P< 0.01) while there was no significant difference in plasma glucose or insulin. Cisapride had no effect on the rate of gastric emptying of the oral glucose load. Mean plasma concentrations of insulin and C-peptide were higher after oral glucose on cisapride than placebo, but these differences were not significantly different. These observations indicate that cisapride may increase glucose-stimulated insulin secretion.

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.

A mechanism for the proarrhythmic effects of cisapride (Propulsid): high affinity blockade of the human cardiac potassium channel HERG

Cisapride (Propulsid) is a gastrointestinal prokinetic agent commonly used to treat nocturnal heartburn as well as a variety of other gastrointestinal disorders. The use of cisapride has been associated with acquired long QT syndrome and ventricular arrhythmias such as torsades de pointes which produces sudden cardiac death. These cardiotoxic effects can be due to blockade of one or more types of K+ channel currents in the human heart. For this reason we compared the effects of cisapride on two cloned human cardiac K+ channels, Kv1.5 and the human ether-a-go-go-related gene (HERG) stably transfected into mammalian cells. Using patch clamp electrophysiology, we found that cisapride was a potent inhibitor of HERG displaying an IC50 value of 44.5 nmol/l when tail currents at -40 mV were measured following a 2 s test depolarization to +20 mV. When HERG currents were measured at the end of prolonged (20 s) depolarizing steps to +20 mV, the apparent affinity of cisapride was increased and measured 6.70 nmol/l. The main effect of cisapride was to enhance the rate of HERG current decay thereby reducing current at the end of the voltage clamp pulse. Furthermore, the potency of cisapride for the HERG channel was similar to that observed for the class III antiarrhythmic agent dofetilide (IC50 = 15.3 nmol/l) and the nonsedating antihistamine terfenadine (IC50 = 56.0 nmol/l). In contrast to its effects on HERG, cisapride inhibited Kv1.5 channel currents weakly displaying an IC50 value of 21.2 micromol/l. It is concluded that cisapride displays specific, high affinity block of the human cardiac K+ channel HERG. It is likely that this interaction underlies the proarrhythmic effects of the drug observed under certain clinical settings.

Effects of cisapride on QTc interval in neonates

AIM

Prospective survey of the effects of cisapride on QTc interval in neonates given cisapride.

METHODS

QTc interval was determined just before and 2.9 (0.9) days after outset of the treatment in 49 neonates treated with cisapride between 1 August 1995 and 29 February 1996.

RESULTS

Cisapride significantly increased QTc interval (p = 0.0001), and this was higher when birthweight or gestational age were lower. The prolongation of QTc interval above the arbitrary value of 0.450 (n = 7) was clinically asymptomatic and was significantly more common in the infants born with a gestational age < or = 33 weeks (n = 6).

CONCLUSION

The findings indicate that cisapride accumulates in less mature neonates. Further pharmacokinetic studies are needed.

Blockage of the HERG human cardiac K+ channel by the gastrointestinal prokinetic agent cisapride

Cisapride, a gastrointestinal prokinetic agent, is known to cause long Q-T syndrome and ventricular arrhythmias. The cellular mechanism is not known. The human ether-á-go-go-related gene (HERG), which encodes the rapidly activating delayed rectifier K+ current and is important in cardiac repolarization, may serve as a target for the action of cisapride. We tested the hypothesis that cisapride blocks HERG. The whole cell patch-clamp recording technique was used to study HERG channels stably expressed heterologously in HEK293 cells. Under voltage-clamp conditions, cisapride block of HERG is dose dependent with a half-maximal inhibitory concentration of 6.5 nM at 22 degrees C (n = 25 cells). Currents rapidly recovered with drug washout. The onset of block by cisapride required channel activation indicative of open or inactivated state blockage. Block of HERG with cisapride after channel activation was voltage dependent. At -20 mV, 10 nM cisapride reduced HERG tail-current amplitude by 5%, whereas, at + 20 mV, the tail-current amplitude was reduced by 45% (n = 4 cells). At -20 and + 20 mV, 100 nM cisapride reduced tail-current amplitude by 66 and 90%, respectively. We conclude that cisapride is a potent blocker of HERG channels expressed in HEK293 cells. This effect may account for the clinical occurrence of Q-T prolongation and ventricular arrhythmias observed with cisapride.

The effect of a single rectal dose of cisapride on delayed gastric emptying

BACKGROUND

Cisapride has an established prokinetic effect in patients with delayed gastric emptying. However, rectal administration of the drug might be preferred in patients with either dysphagia or nausea due to gastroparesis.

AIM

To determine the effect of a single rectal dose of cisapride 60 mg on gastric emptying in patients with delayed gastric emptying.

METHODS

Thirty-two patients (16 males, 16 females) with demonstrated delayed gastric emptying received a single dose of two suppositories containing either cisapride (2 x 30 mg) or placebo, according to a double-blind randomized crossover design. Three hours after administration of the suppositories, the patients received a radio-labelled test meal and radio-opaque markers for measurement of gastric emptying.

RESULTS

The mean t1/2 after cisapride administration (76 min, 95% CI: 68-95) was significantly shorter (P = 0.005: n = 28, per-protocol analysis) than after placebo administration (104 min, 81-126). Four hours after ingestion of the meal significantly fewer radio-opaque markers remained in the stomach after cisapride than after placebo administration (P < 0.05). Mild to moderate adverse events, mainly involving the gastrointestinal tract, were reported in 10 patients (31%) after cisapride treatment and in four patients (13%) after placebo (N.S.: n = 32).

CONCLUSION

A single suppository dose of cisapride 60 mg significantly accelerates gastric emptying of the solid phase of a meal and of radio-opaque markers in patients with previously demonstrated delayed gastric emptying.

Use of cisapride in treatment of constipation in children

BACKGROUND

Chronic constipation is a common problem in children. We observed the effects of cisapride in the management of idiopathic constipation in children.

METHODS

Thirty-seven children with a history of constipation (i.e., pain and difficulty or delay in defecation for > 3 months) were recruited and randomly assigned to 8 weeks of treatment with either cisapride, 0.2 mg/kg three times daily, or matching placebo after a 2-week run-in period in a double-blind, parallel-group study design. In phase 1 (2 weeks), patients had plain abdominal radiographs to assess degree of faecal load, and those with impaction were given laxatives. After satisfactory clearance of faeces, total gastrointestinal transit time and orocaecal transit time were measured. In phase 2, after 8 weeks of treatment with either cisapride or placebo (0.2 mg/kg t.d.s.), the transit studies were repeated.

RESULTS

Compared with placebo, cisapride did not improve either stool frequency or transit time in this study population.

CONCLUSION

This study did not demonstrate a clinical role for the use of cisapride in the treatment of idiopathic constipation in children.

Cisapride and erythromycin prokinetic effects in gastroparesis due to type 1 (insulin-dependent) diabetes mellitus

BACKGROUND

Erythromycin, a macrolide antibiotic, has been shown to have gastric prokinetic effects and has been proposed as an alternative therapeutic option for diabetic gastroparesis. However, its efficacy has not yet been compared with that of other prokinetic drugs.

AIMS

The purpose of the present study was to compare the effects of erythromycin (250 mg 60 min before meals) and cisapride (10 mg 30 min before meals) on gastric emptying of healthy subjects and insulin-dependent diabetics.

PATIENTS AND METHODS

Six type 1 diabetic patients with a previous scintigraphic demonstration of gastroparesis and five healthy subjects were recruited for the study. Gastric emptying was scintigraphically studied by labelling the solid component of a standard test meal. Three scintigraphic studies, spaced at least 3 days apart, were carried out on each subject, basally and after erythromycin or cisapride.

RESULTS

Cisapride significantly accelerated gastric emptying in both the healthy subjects and the diabetic patients without any significant effect on the lag-time, whereas erythromycin in addition to a significant improvement of the overall gastric emptying also showed a pronounced effect on the lag-time in both groups (controls 25 +/- 5 vs. 37 +/- 8 min, P < or = 0.04; diabetics 65 +/- 11 vs. 112 +/- 16 min, P < 0.03).

CONCLUSIONS

Erythromycin may represent an effective therapeutic alternative to more established forms of treatment in patients with diabetic gastroparesis, especially when other drugs have failed.

[Long QT syndrome under cisapride in neonates and infants]

BACKGROUND

Cisapride is frequently used in the newborn and infant for treatment of gastroesophageal reflux. Twisting-spikes have been reported in adults due to overdosage or therapeutic interaction. We report seven cases of QT prolongation in infants treated with cisapride.

PATIENTS AND METHODS

Seven children (one full-term, two mature preterms, four preterm babies), aged (mean, range) 41.8 +/- 21 days (14-79) weighing 2.1 +/- 1.1 kg (1.2-4), free from any cardiac abnormality, except one patent ductus arteriosus, have been studied by ECG and Holter monitoring. They received cisapride at a mean dose of 1.31 +/- 0.2 mg/kg/d (between 1 and 1.7 mg/kg/d).

RESULTS

The corrected QT (QTc: N < 450 ms) was increased to 486 ms (450-540) with a notched T-wave pattern. No arrhythmia was detected. In five cases, cisapride was stopped and changed to metoclopramide. Cisapride dosage was reduced to 0.8 mg/kg/d in the two others. No other therapeutic modification was done. A control ECG performed 48 hours after therapeutic changes showed a QTc shortening of 74 +/- 18 ms (45-90) and the disappearance of the notches independent of any heart rate changes, leading to normal QTc values: 413 +/- 21 ms (390-440).

CONCLUSION

High cisapride dosage in preterm, newborns and infants seems to favor QT prolongation which is reversible when dosage is reduced or drug is stopped. The use of cisapride in combination with other drugs known to increase QT should be done with extreme caution.

Effects of 5-HT4-receptor agonists, cisapride, mosapride citrate, and zacopride, on cardiac action potentials in guinea pig isolated papillary muscles

The purpose of this study was to examine the effects of 5-HT4-receptor agonists cisapride, mosapride citrate (mosapride), and zacopride on action potentials (APs) in guinea pig isolated papillary muscles. Cisapride (0.1-3 microM) concentration-relatedly prolonged the duration of APs (APD) without affecting the other AP parameters. Mosapride and its main metabolite M1 (des-4-fluoro-benzyl-mosapride) did not affect APs at 10 microM. Zacopride at 10 microM shortened APD, and the APD-shortening effect was not affect by GR113808 (10 microM), a 5-HT4-receptor antagonist. The cisapride (1 microM)-induced prolongation of APD was not affected by GR113808 (10 microM), ritanserin (10 microM), a 5-HT2A/2C-receptor antagonist, or prazosin (10 microM), an alpha 1-receptor antagonist. The same concentrations of GR113808, ritanserin, and prazosin did not affect APD. Clofilium, a class III antiarrhythmic agent, prolonged APD; the effect was more pronounced at a stimulus frequency of 0.3 Hz than at 2.0 Hz. Cisapride did not exert such reverse use dependence, suggesting that its mechanism of action is different from that of clofilium. These results suggest that cisapride prolongs APD without involvement of 5-HT2, 5-HT4, or alpha 1 receptors. Mosapride is unlikely to induce the prolongation of electrocardiographic QT intervals correlated with the prolongation of APD in isolated ventricular muscles.

Pharmacokinetics of cefetamet pivoxil and interaction with cisapride and N-acetylcysteine

OBJECTIVE: To evaluate the pharmacokinetics of cefetamet pivoxil and possible interaction with N-acetylcysteine and cisapride in healthy volunteers. METHODS: In a double-blind, randomized three-way crossover study with 12 healthy male volunteers, serum and urine concentrations of cefetamet were determined over 12 h by a validated bioassay method after oral administration of 0.5 g cefetamet pivoxil and, randomly, placebo, 5x20 mg cisapride, or 0.6 g N-acetylcysteine. RESULTS: The study medications were well tolerated, although there were 10 cases of altered bowel movements, two cases of mild, transient headache and one case of increased serum transferase levels (AST and ALT). The mean peak serum level of cefetamet pivoxil in the placebo group was 4.86plus minus1.35 mg/L. The urine recovery/24 h in the placebo group was 41.9plus minus3.8% of the oral dose. The elimination half-life was 3.56plus minus0.92 h. N-Acetylcysteine had no effect on the pharmacokinetics of cefetamet pivoxil. With concomitant administration of cisapride there was an accelerated absorption of cefetamet pivoxil and a slightly increased Cmax of cefetamet. The Cmax values differed significantly (p<0.05) only between the cisapride group (5.76plus minus1.50 mg/L) and the N-acetylcysteine group (4.53plus minus1.18 mg/L). CONCLUSION: None of the small pharmacokinetic differences between the three groups is expected to have any relevance in the treatment of infectious diseases with cefetamet pivoxil.

Gastrointestinal motor activity in conscious ferrets

Gastrointestinal motility was measured with force transducers in conscious ferrets. The gastrointestinal motility pattern in both the interdigestive and digestive states was similar to that reported for humans. The activity front, phase III contractions of the migrating motor complex, occurred cyclically in the antrum and migrated to the duodenum and ileum in the interdigestive state, and relatively low-amplitude contractions were sustained in the antrum, duodenum and ileum in the digestive state. Colonic motility was characterized by basal relatively low-amplitude contractions and a single high-amplitude contraction preceding defecation. Cisapride (0.3-3 mg/kg s.c.) enhanced antral and colonic motility. This ferret model will help the investigation and evaluation of drug effects on gastrointestinal motility in humans.

VB20B7, a novel 5-HT-ergic agent with gastrokinetic activity. I. Interaction with 5-HT3 and 5-HT4 receptors

This study describes the in-vitro interaction of the gastrokinetic agent 2[1-(4-piperonyl)piperazinyl]benzothiazole (VB20B7) with the 5-hydroxytryptamine 5-HT3 and 5-HT4 receptor subtypes, using functional as well as radioligand binding studies. The benzamide derivative cisapride was used as a comparison. In radioligand binding assays VB20B7 showed, like cisapride, a weak affinity at 5-HT3 receptors from rat cerebral cortex. The new compound lacked any affinity at other 5-HT receptors or at dopaminergic D2 receptors, whereas cisapride showed high affinity for the 5-HT4 receptors from guinea-pig hippocampus and moderate affinity at dopaminergic D2 receptors. In the non-stimulated guinea-pig ileum, the concentration-response curves to the specific 5-HT3 agonist 2-Me-5-HT and to 5-HT were shifted to the right by VB20B7. In the rat oesophagus tunica muscularis mucosae preparation (TMM), VB20B7 was evaluated for its activity at 5-HT4 receptors. VB20B7 behaved as a 5-HT4 receptor agonist, inducing a concentration-dependent relaxation of the preparation precontracted with carbachol. In this preparation, VB20B7 and cisapride were able to stimulate adenylate cyclase activity, an effect probably mediated through activation of 5-HT4 receptors, as can be inferred from the blockade by the 5-HT4 antagonist, tropisetron, of the enhanced cAMP formation. However, consistent with the lack of affinity at central 5-HT4 receptors, VB20B7 did not stimulate cAMP formation in guinea-pig hippocampal slices. VB20B7 also caused an increase in the twitch response of the transmurally stimulated guinea-pig ileum, although at a concentration higher than cisapride. This effect was blocked by desensitization of the 5-HT4 receptor with 5-MeOT and also by the 5-HT4 receptor antagonist tropisetron. Both VB20B7 and cisapride increased the K(+)-evoked acetylcholine release in this preparation. The results show that VB20B7 possesses affinity for 5-HT4 receptors located in the rat TMM and guinea-pig ileum preparations, but is devoid of affinity at central 5-HT4 receptors. In addition, VB20B7 shows low to moderate affinity at both central and peripheral (enteric) 5-HT3 receptors. The interaction of VB20B7 with the peripheral 5-HT4 and 5-HT3 receptors may be relevant for the gastrokinetic effects of the new compound.

Effect of lactulose and fiber-rich diets on bile in relation to gallstone disease: an update

The primum movens in cholesterol gallstone formation is hepatic cholesterol hypersecretion and chronic supersaturation of bile. From this event a cascade of contributing factors can be differentiated: (i) Motility defects with impaired gallbladder contractility and gallbladder stasis, but also with small and large intestinal hypomotility. (ii) Multiple biochemical defects in gallbladder bile with increased biliary proteins, increased deoxycholic acid and rapid crystallization of biliary cholesterol from supersaturated unstable vesicles. There is considerable evidence that slow intestinal and colonic transit can increase the deoxycholic acid pool size and biliary cholesterol saturation. Changes in intestinal transit influence the anaerobic bacterial enzymatic biotransformation of conjugated cholate to more hydrophobic deoxycholate. This leads to biliary cholesterol hypersecretion and gallstone formation. Prokinetic drugs or administration of lactulose or fiber products like bran can change the slow intestinal transit favourably with subsequent reduction in deoxycholic acid formation and cholesterol saturation of bile. Whether these applications are indeed of value in the long-term prevention of gallstone disease, however, is doubtful, since fiber-rich diet in prevention of gallstone recurrence after complete gallstone dissolution was not successful.

Effects of cisapride on ulcer formation and gastric secretion in rats: comparison with ranitidine and omeprazol

1. The antiulcerogenic effects of cisapride, a potent benzamide-stimulating gastrointestinal motility agent, were studied on cold-resistant and pylorus-ligated gastric ulcers. Acidity, composition of gastric secretion, and quantitative and qualitative changes on mucus glycoprotein content were also determined. These effects were compared with those of ranitidine (50 mg/kg) and omeprazol (10 mg/kg). 2. Oral cisapride (10-100 mg/kg) dose-relatedly and significantly (P < 0.01, P < 0.05) decreased the severity of the lesions induced by cold-resistant stress. In stressed rats, cisapride increased the amount of mucus secretion and markedly enhanced the glycoprotein content. Morphometric evaluation of mucus secretion revealed a significant increase in both the PAS area (neutral glycoproteins) and Alcian blue area (sulfated glycoproteins). 3. In 4 h pyloric-ligated animals, cisapride (10-100 mg/kg) showed a significant reduction in the number and severity of ulcers (P < 0.01) and histamine concentration (P < 0.01, P < 0.001). In addition, at the highest doses (50-100 mg/kg), cisapride produced a significant decreases in acidity; however, it did not alter the gastric volume secretion or pepsin concentrations. 4. These results suggest that cisapride shows antiulcerogenic effects which could possibly be explained through antisecretory and cytoprotective mechanisms involving an enhancement of cuality and production of gastric mucus.

Management of gastrointestinal motility disorders. A practical guide to drug selection and appropriate ancillary measures

The focus of management of gastrointestinal motility disorders should be to improve survival and quality of life. Some motor disorders are annoying, but are compatible with virtually normal activity and carry no significant life risk. Conversely, other motor disorders are highly incapacitating and may shorten life expectancy because of complications and nutritional impairment. Management is based first on establishing the correct diagnosis and prognosis; secondly, on adjusting therapy to the severity of illness; and thirdly, on preventing significant complications. Simple recommendations on appropriate changes in lifestyle and reassurance may suffice in mild cases. Pharmacological therapy and, exceptionally, surgical or nutritional measures may be required in other patients. Generally, pharmacological agents should be directed towards correcting specific pathophysiological abnormalities, but this is not always possible. Symptomatic relief may be achieved on an empirical basis. Long term treatment may often require the combination of different therapeutic approaches either sequentially or simultaneously.

Cisapride. Drug interactions of clinical significance

Cisapride is a prokinetic agent which restores motility of the gastrointestinal tract in conditions of decreased bowel transit. It may also alter the absorption of coadministered drugs. The absorption of morphine, diazepam, cyclosporin, alcohol (ethanol) and levodopa are increased. Initial absorption of cimetidine and raniditine is also increased, but overall absorption is lower due to increased bowel transit. The absorption of digoxin, propranolol and the anticoagulants warfarin and phenprocoumon appears unaffected by cisapride, although increase thrombotest values were seen with acenocoumarol (nicoumalone). Drug interactions leading to increased plasma concentrations of cisapride may produce an increase in adverse effects. The most important of these is QT interval prolongation and ventricular arrhythmias. Phenytoin does not appear to affect protein binding of cisapride. Cisapride metabolism is inhibited by the antifungals ketoconazole, fluconazole, itraconazole and miconazole, and by the antibacterials erythromycin, troleandomycin and clarithromycin. Cisapride should not be coadministered with these drugs. Cimetidine produces a small increase in cisapride plasma concentrations, which may be due to inhibition of metabolism. Cisapride absorption is unaffected by other antacids. Atropine may reverse the cisapride-induced increase in peristalsis. Prescribers should remain vigilant to the presence of these and other, as yet unreported, reactions.

Respiratory complications of gastroesophageal reflux disease

There is a relationship between gastroesophageal reflux disease and certain respiratory symptoms and findings. Among these are cough, laryngitis, and wheezing dyspnea. The pathophysiology of these conditions can vary from actual aspiration of gastric content to esophageal mucosal inflammation with the respiratory symptoms induced by a vagally mediated reflex mechanism.

Cytoprotective activity of cisapride on experimental gastric mucosal lesions induced by ethanol. Role of endogenous prostaglandins

The antiulcer effects and protective mechanisms of cisapride, a prokinetic benzamide agonist of 5-HT3 and antagonist of 5-HT4 receptors, were investigated in gastric mucosal injury induced by pretreatment with 50% v/v ethanol in rats. The duration of the protective effect was also studied and the results were compared with those of 5-HT. 240 min after administration of cisapride (10, 25 and 50 mg/kg) the total area of gastric lesions decreased significantly, in macroscopical and histological evaluations, and the mucus, hexosamine, and sulphated glycoprotein content were significantly increased. Indomethacin partially reversed cisapride protection suggesting that the beneficial antiulcer effects of this drug could be mediated in part by prostaglandins. This study confirms that this benzamide, in this experimental model, enhances gastric PGE2 production. We also investigated the time course of action of 5-HT, 30-240 min before ethanol administration, and our study not only demonstrates the ulcerogenic action of the amine (30 min of pretreatment) but also its protective nature, shown macroscopic and microscopically, after 240 min of its administration, without any effect on PGs production. These findings suggest a new gastroprotective feature of cisapride partly explained through a prostaglandin-dependent mechanism and possibly independent of its 5-HT activity.

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.

Placebo-controlled trial of cisapride in postgastrectomy patients with duodenogastroesophageal reflux

Medical treatment of duodenogastroesophageal reflux in postgastrectomy patients has been disappointing. Using ambulatory esophageal bilirubin monitoring, we evaluated the efficacy of cisapride in this disorder. Ten chronically symptomatic partial gastrectomy patients (5 Billroth I, 5 Billroth II; 8 men; average age 57) with duodenogastroesophageal reflux were randomized to four weeks of either placebo or cisapride (20 mg four times a day) in a double-blind crossover study. Significantly improved patients continued to take cisapride for an additional four months. Duodenogastroesophageal reflux was assessed at baseline and after four weeks on each therapy. Daily diary recorded symptoms and mean monthly scores were determined. Global symptom improvements were assessed at the end of each treatment period. Compared to placebo, cisapride significantly (P < 0.05) decreased duodenogastroesophageal reflux. Overall symptom improvements were assessed at the end of each treatment period. Compared to placebo, cisapride significantly (P < 0.05) decreased duodenogastroesophageal reflux. Overall symptoms improved in 70% of patients on cisapride compared to 10% on placebo (P < 0.01). Mean monthly scores significantly (P < 0.05) improved for abdominal pain, regurgitation, and belching. These symptoms remained improved after four months of chronic therapy. We conclude that cisapride significantly reduces duodenogastroesophageal reflux and results in short- and long-term symptom improvements in postgastrectomy patients and that cisapride offers the first successful medical therapy for duodenogastroesophageal reflux in postgastrectomy patients.

5-HT4 receptors are not involved in the control of small intestinal transit in the fasted conscious rat

Cisapride and metoclopramide are used clinically in the treatment of gastro-oesophageal reflux disease and also in a variety of motility disorders of the gastrointestinal tract. Their prokinetic effect is thought to be due to the augmentation of acetylcholine release from the myenteric plexus, an effect likely to be mediated through the stimulation of 5-HT4 receptors. The role of 5-HT4 receptors in the control of intestinal motility in man and animals is not clear, therefore we have investigated their role in the control of small intestinal transit in the rat. Radioactive microspheres were administered into the proximal duodenum of fasted conscious rats through an indwelling cannula. The extent of small intestinal transit was examined by determining the distribution of the microspheres within the intestine. Following i.p. injection small intestinal transit was inhibited (78%) by atropine (3 mg/kg), suggesting the presence of a basal cholinergic influence. Furthermore, in the presence of p-amino clonidine intestinal transit was stimulated (126%) by bethanechol (3 mg/kg). The 5-HT4 receptor agonists cisapride (1.0 mg/kg) and zacopride (1.0 mg/kg) failed to increase small intestinal transit. The 5-HT4 receptor selective antagonist GR125487 (1 mg/kg) was also without effect. These data suggest that 5-HT4 receptors are not involved in the control of small intestinal transit in the fasted conscious rat.

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.

The role of gastric mucosal sulphydryls in the ulcer-protecting effects of cisapride

The present study was designed to examine the role of endogenous sulphydryls (SHs) in the gastro-protection induced by cisapride (CIS) (10, 25 and 50 mg kg-1 i.p.), a potent benzamide stimulating gastrointestinal motility in mucosal injury induced by 50% v/v ethanol. Results were compared with those of 5-hydroxytryptamine (5-HT) (10mg kg-1). Ethanol mucosal damage was significantly reduced by treatment with CIS and 5-HT. On the contrary, administration of n-ethylmaleimide (NEM) (10 mg kg-1) an SH alkylator, markedly worsened lesion formation and counteracted the protective effect of CIS. Rats pretreated with CIS significantly increased the total sulphydryls as reflected in the non-protein and protein fractions however, 5-HT treatment showed a fall in the non-protein level. The present results suggest that 5-HT-ergic dependent mechanisms have no relation to the gastro-protection afforded by CIS in this experimental model. It is possible that mucosal SHs could be involved.

Cisapride for the treatment of chronic idiopathic constipation

Cisapride appears to be useful as therapy for chronic constipation that is not associated with underlying organic abnormalities or pregnancy and that is refractory to other treatments, such as increased dietary fiber intake or bulk laxatives. Dosages of cisapride that have demonstrated efficacy in chronic constipation range from 5 mg po tid to 20 mg po bid. Treatment for 8-12 weeks may be necessary for an optimal effect to occur. Further studies are needed to evaluate the most effective dosage regimen for the treatment of constipation and to compare the efficacy and cost-efficiency of cisapride with those of conventional therapy. Until these studies are completed, cisapride should not be recommended routinely for patients with constipation. However, it may be a viable option for patients with chronic idiopathic constipation that is refractory to conventional therapy.

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.

Pharmacological characterization of two novel and potent 5-HT4 receptor agonists, RS 67333 and RS 67506, in vitro and in vivo

1. The pharmacology of two novel 5-HT4 receptor agonists, RS 67333 (1-(4-amino-5-chloro-2-methoxy-phenyl)-3-[1(n-butyl)-4-piperidinyl]-1- propanone HCl) and RS 67506 (1-(4-amino-5-chloro-2-methoxy-phenyl)-3-[1-(2-methyl sulphonylamino)ethyl-4-piperidinyl]-1-propanone HCl) have been assessed in vitro and in vivo. 2. RS 67333 and RS 67506 exhibited affinities (pKi = 8.7 and 8.8, respectively) for the 5-HT4 binding sites, labelled with [3H]-GR 113808, in guinea-pig striatum. The Hill coefficients from these displacement curves were not significantly different from unity. The compounds exhibited lower affinities (< 6.0) at several other receptors including 5-HT1A, 5-HT1D, 5-HT2A, 5-HT2C, dopamine D1, D2 and muscarinic M1-M3 receptors. However, RS 67333 and RS 67506 did exhibit affinities for the sigma 1 (pKi = 8.9 and 7.9, respectively) and sigma 2 (pKi = 8.0 and 7.3, respectively) binding sites. 3. At the 5-HT4 receptor mediating relaxation of the carbachol-precontracted oesophagus, RS 67333 and RS 67506 acted as potent (pEC50 8.4 and 8.6, respectively), partial agonists (intrinsic activities, with respect to 5-HT were 0.5 and 0.6, respectively) with respect to 5-HT. Relaxant responses to RS 67333 or RS 67506 were surmountably antagonized by GR 11308 (10 nM), with apparent affinities (pKB) of 9.1 and 9.0, respectively. RS 67333 and RS 67506 induced dose-dependent increases in heart rate of the anaesthetized micropig (ED50 4.9 and 5.4 micrograms kg-1, i.v.), with maximal increases of 35 and 47 beats min-1, respectively. 4. RS 67333 and RS 67506, therefore, acted as potent, partial 5-HT4 receptor agonists in vitro and in vivo. These compounds, by virtue of their high potency and selectivity, may have some utility in elucidating the physiological role of 5-HT4 receptors.