Risk factors, co-medication, and concomitant diseases: their influence on the outcome of therapy with cisapride

Prolongation of the QT interval and cardiac arrhythmias associated with cisapride: limitations of the pharmacoepidemiological studies conducted and proposals for the future

Not all hazards can be identified from clinical studies prior to marketing of medicinal products. Pre-marketing large-scale trials for cisapride did not report any serious cardiac arrhythmias. After a long period of availability in several countries it was withdrawn in 2000 because of reports of serious, and in many cases fatal, cardiac events. Whilst spontaneous reporting systems for adverse drug reactions (ADRs) have limitations such as under-reporting, they are an effective system for signal generation, particularly of rare ADRs. Pharmacoepidemiological studies aim to identify and calculate the incidence of adverse reactions, with increased sensitivity to less common ADRs compared to randomised controlled trials, yet cohort sizes may be insufficient to detect very rare ADRs such as drug-induced Torsade de Pointes, with an estimated incidence of the order of 1 per 12,000 to 1 per 120,000 patients. Several pharmacoepidemiological studies investigated adverse events associated with cisapride, one of which specifically examined the association between serious cardiac arrhythmias and cisapride. These observational studies were conducted using large population databases, but each failed to identify sufficient cases to establish a causal relationship. Explanations include that the cohort sample sizes were too small, and either under-, or mis-reporting of events of interest may have occurred. To estimate the risk of very rare adverse events, pharmacoepidemiological studies require very large numbers. Furthermore, the events in question need to be clinically recognisable by doctors and adequately documented in patients' notes, computer records, or on study questionnaires. The establishment of a national registry for drug-induced QT prolongation to identify cases and correlate clinical information may help to better identify these rare ADRs earlier. Such proactive surveillance could avoid unnecessary delays for other drugs where QT prolongation and serious cardiac arrhythmias may be an issue.

Review Article: pain versus discomfort--is differentiation clinically useful?

Functional dyspepsia is highly variable in its clinical presentation and multifactorial in its underlying causes. Since many of the symptoms included in the definition of dyspepsia are intuitively suggestive of different pathogenic mechanisms, it has been proposed that patients with functional dyspepsia be divided into distinct dyspepsia sub-groups according to symptom clusters. The goal was to classify patients more homogeneously for research purposes as well as to target treatment. However, recent epidemiological, pathophysiological, and clinical studies indicate that a priori definitions based on the presence/absence of symptoms or clusters of symptoms have no clinical utility due to the considerable overlap between symptoms, as well as the poor correlation between pathogenic factors and responses to treatment. Attention is now focused on identifying predominant symptoms. Recent studies suggest that the analysis of predominant symptoms, demographic features, and overlapping digestive syndromes can help to identify dyspepsia sub-groups with different underlying pathophysiological features and aid in selecting appropriate treatment. The utility of this approach has been demonstrated in gastro-oesophageal reflux disease, which can be reliably diagnosed and managed on the basis of the presence and severity of the predominant symptom, heartburn. It is likely that precise symptom definitions and history-taking will be of pivotal importance in management strategies for functional dyspepsia.

Nomenclature of dyspepsia, dyspepsia subgroups and functional dyspepsia: clarifying the concepts

There is international agreement that dyspepsia refers to pain or discomfort centered in the upper abdomen. However, the term 'discomfort' has been variably defined. While other symptoms may often be simultaneously present, gastro-oesophageal reflux disease can usually be clearly distinguished by the presence of predominant heartburn. Dyspepsia is a frequent reason for consultation in primary care and in gastrointestinal practice. With the widespread availability and utilization of endoscopy, it has become evident that a structural (or organic) explanation is found in only a minority of patients presenting with dyspepsia. Operationally, functional dyspepsia is defined as persistent or recurrent dyspepsia for 3 or more months in the absence of a clinically identifiable structural disease causing the symptoms. It has been proposed, based on symptoms, that functional dyspepsia be subdivided into symptom subgroups to promote patient homogeneity. The initially proposed 'clustering' of symptoms into ulcer-like and dysmotility-like functional dyspepsia has proved a dismal failure because of the considerable overlap observed, the lack of stability over time and the failure to identify robust pathophysiological abnormalities or responses to therapy. A subcategorization based upon the most bothersome symptom is theoretically more attractive but needs to be prospectively and rigorously tested.

Meta-analysis of antisecretory and gastrokinetic compounds in functional dyspepsia

In view of therapeutic advances, we carried out meta-analysis of results from 18 randomized, controlled clinical studies to update a previous meta-analysis and to provide an overview of clinical trials involving treatment of functional dyspepsia. The studies were included only if they satisfied inclusion and exclusion criteria and assessed treatment of functional dyspepsia with the antisecretory compounds cimetidine and ranitidine and the gastrokinetic compounds cisapride and domperidone. Outcomes of each of these trials were classified in terms of differences in therapeutic success between active treatment and placebo. For antisecretory treatments, the 95% confidence intervals for the difference in therapeutic success between active treatment and placebo were inconsistent for cimetidine, but analysis of both ranitidine trials gave favorable results. For the gastrokinetic compounds cisapride and domperidone, the differences in success rates were generally higher and more in favor of active treatment than placebo. By combining the results from both antisecretory treatments and comparing them with the combined results for gastrokinetic compounds, we observed that gastrokinetic compounds had a greater difference in success rates than did antisecretory agents. Overall, our meta-analysis shows that antisecretory treatment with cimetidine or ranitidine offers little advantage over placebo, whereas gastrokinetic treatment with cisapride or domperidone is significantly better than placebo for treatment of functional dyspepsia.

Management of dyspepsia in general practice. A critical assessment

The International Gastro Primary Care Group (IGPCG) Upper Gastrointestinal Disease Management Plan is mainly characterised by the proposal that management of patients with upper gastrointestinal syndromes be based on the predominant symptom, rather than on symptom clusters. Although no study has directly tested this hypothesis in general practice, some data indirectly support the proposal. Classification based on the relevance of specific symptoms could identify distinct subgroups of patients with functional dyspepsia with at least partially different features. Data obtained from the literature are discussed and evaluated in relation to the suggested algorithm. Overall, this management plan for patients with dyspepsia seems to be both safe and effective. However, there is a need for prospective studies evaluating its actual validity.

Transient paroxysmal dystonia in an infant possibly induced by cisapride

The case is reported of an infant presenting paroxysmal dystonia during cisapride theraphy. We suggest that this drug, a substituted benzamide, probably interfered with the age-related modification of striatal neurotransmitters, provoking extrapyramidal symptoms. Considering the widespread use of cisapride in early infancy for the treatment of gastrointestinal disorders, attention must be drawn to this possible side effect.

Gastric emptying in critically ill patients is accelerated by adding cisapride to a standard enteral feeding protocol: results of a prospective, randomized, controlled trial

OBJECTIVE

To investigate the effect of cisapride, a relatively new prokinetic agent, on gastric emptying in critically ill patients.

DESIGN

Prospective, randomized, controlled study.

SETTING

Adult medical/surgical intensive care unit in a university hospital.

PATIENTS

Twenty-one consecutively enrolled patients, requiring prolonged mechanical ventilation and enteral feeding.

INTERVENTIONS

Patients were randomized to receive either no cisapride or 10 mg of cisapride four times daily, which was added to a standard enteral nutrition feeding protocol.

MEASUREMENTS AND MAIN RESULTS

Gastric emptying was evaluated by daily measurements of gastric residue and on days 5 through 7 by bedside scintigraphy. Normal values for gastric clearance of a tracer-labeled test meal and for measurements obtained in the supine position were determined in ten healthy volunteers. The mean time at which 50% of the technetium 99m-labeled test meal was eliminated from the stomach (T 1/2) in this control group was 31 +/- 15 mins. In ten critically ill patients (enteral nutrition group), gastric emptying was markedly delayed after 5 to 7 days of enteral feeding (mean T 1/2 = 78 +/- 40 mins; p < .002 as compared with the control group). In contrast, patients treated with cisapride (cisapride group) showed an accelerated gastric emptying (mean T 1/2 = 18 +/- 7 mins; p > .05 as compared with controls; p < .005 as compared with enteral nutrition group). The mean gastric residue over a 1-wk period was also significantly lower in the cisapride group than in the enteral nutrition group (17.7 +/- 8.9 vs. 94.5 +/- 33.4 mL; p < .001).

CONCLUSIONS

The data indicate that gastric emptying in critically ill, sedated, and mechanically ventilated patients can be significantly improved by adding cisapride to a routine enteral feeding protocol.

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

Cisapride is an orally administered prokinetic agent which facilitates or restores motility throughout the length of the gastrointestinal tract. It is a substituted piperidinyl benzamide, chemically related to metoclopramide, but unlike metoclopramide, cisapride is largely devoid of central depressant or antidopaminergic effects. In placebo-controlled trials, cisapride improved healing rates and symptoms in both adults and children with reflux oesophagitis. Maintenance therapy with cisapride at half the healing dose is effective in reducing the incidence of relapse. Symptoms are also alleviated in patients with functional dyspepsia, and gastric emptying and symptoms are improved in most patients with gastroparesis, an effect which is sustained during long term administration. However, the efficacy of cisapride in end-stage gastroparesis remains less clear. Cisapride increases stool frequency in patients with chronic constipation, and limited data suggest that the drug may also be beneficial in treating chronic intestinal pseudo-obstruction and irritable bowel syndrome. Cisapride demonstrated efficacy comparable with or superior to that of metoclopramide, and was at least as effective as cimetidine and ranitidine in patients with reflux disease. In patients with functional dyspepsia, cisapride has shown at least equal efficacy to domperidone, metoclopramide and ranitidine, and superior efficacy to cimetidine in the small comparative trials conducted to date. Adverse effects in patients receiving cisapride are generally transient and mild, with abdominal cramping, borborygmi, diarrhoea or loose stools most frequently reported. Central nervous system adverse effects are rare. Thus, with its favourable tolerability profile and demonstrated efficacy in a variety of gastrointestinal motility disorders, the position of cisapride as a valuable agent in the management of patients with gastrointestinal motility disorders is strengthening. However, larger well-controlled comparative trials of the drug with other agents are necessary before the relative position of cisapride in therapy can be categorically defined.