Effects of cisapride on QT interval in children

Thoracic epidural analgesia prolongs postoperative QT interval on electrocardiogram in major non-cardiac surgery: a randomized comparison and a prospective cohort analysis

Introduction: Prolongation of QT interval on electrocardiogram can be associated with perioperative lethal arrhythmia. Epidural analgesia is a commonly used modality to relieve surgical pain by blocking sensory nerves, which also blocks the autonomic nervous system and can affect QT interval. Since patient monitoring becomes much less frequent after surgery than intraoperative period, we investigated the effects of epidural analgesia on postoperative QT interval with a randomized clinical trial and a prospective cohort study. Methods: In a randomized study, we assigned 60 patients undergoing thoracic epidural analgesia to an epidural analgesia or no-epidural analgesia group, in which 3 ml/h of 0.25% epidural levobupivacaine (7.5 mg/h) was administered only in the epidural analgesia group during surgery. The primary outcome was the postoperative heart rate-corrected QT interval. In a prospective cohort study, patients were assigned to receive 5 ml/h epidural levobupivacaine (12.5 mg/h). The plasma concentration of levobupivacaine was measured using liquid chromatography-mass spectrometry. Results: The median postoperative corrected QT interval interval with 3 ml/h epidural levobupivacaine was significantly longer than that without epidural analgesia. Using multiple regression analysis for the factors known to affect postoperative corrected QT interval interval, epidural analgesia was found to be an independent variable for prolongation, and the mean difference of the corrected QT interval interval with or without epidural analgesia was 23 ms after adjustment. The median plasma concentration of levobupivacaine at the end of surgery was 164 ng/ml with 3 ml/h epidural levobupivacaine, and the correlation coefficient to the postoperative corrected QT interval interval was 0.14, showing a not significant correlation. A prospective cohort study showed that 5 ml/h epidural levobupivacaine significantly prolonged postoperative corrected QT interval interval compared to preoperative baseline. The median plasma concentration of levobupivacaine was 166 ng/ml with 5 ml/h, the correlation coefficient of which showed no significant correlation. Conclusion: Thoracic epidural analgesia could enhance postoperative corrected QT interval prolongation after general anesthesia. The mechanism is possibly caused by blocking neighboring or part of the cardiac sympathetic nerves, rather than by systemic effects of epidurally administered levobupivacaine. Clinical trial number: UMIN000013347 for the randomized study and UMIN000041518 for the prospective cohort study, which were registered at University hospital Medical Information Network Center.

QTc Interval Reference Values and Their (Non)-Maturational Factors in Neonates and Infants: A Systematic Review

QTc interval measurement is a widely used screening tool to assess the risk of cardiac diseases, arrhythmias, and is a useful biomarker for pharmacovigilance. However, the interpretation of QTc is difficult in neonates due to hemodynamic maturational changes and uncertainties on reference values. To describe trends in QTc values throughout infancy (1 year of life), and to explore the impact of (non)-maturational changes and medicines exposure, a structured systematic review (PROSPERO CRD42022302296) was performed. In term neonates, a decrease was observed over the first week of life, whereafter values increased until two months of age, followed by a progressive decrease until six months. A similar pattern with longer QTc values was observed in preterms. QTc is influenced by cord clamping, hemodynamic changes, therapeutic hypothermia, illnesses and sleep, not by sex. Cisapride, domperidone and doxapram result in QTc prolongation in neonates. Further research in this age category is needed to improve primary screening practices and QTcthresholds, earlier detection of risk factors and precision pharmacovigilance.

Ventricular voltage-gated ion channels: Detection, characteristics, mechanisms, and drug safety evaluation

Cardiac voltage-gated ion channels (VGICs) play critical roles in mediating cardiac electrophysiological signals, such as action potentials, to maintain normal heart excitability and contraction. Inherited or acquired alterations in the structure, expression, or function of VGICs, as well as VGIC-related side effects of pharmaceutical drug delivery can result in abnormal cellular electrophysiological processes that induce life-threatening cardiac arrhythmias or even sudden cardiac death. Hence, to reduce possible heart-related risks, VGICs must be acknowledged as important targets in drug discovery and safety studies related to cardiac disease. In this review, we first summarize the development and application of electrophysiological techniques that are employed in cardiac VGIC studies alone or in combination with other techniques such as cryoelectron microscopy, optical imaging and optogenetics. Subsequently, we describe the characteristics, structure, mechanisms, and functions of various well-studied VGICs in ventricular myocytes and analyze their roles in and contributions to both physiological cardiac excitability and inherited cardiac diseases. Finally, we address the implications of the structure and function of ventricular VGICs for drug safety evaluation. In summary, multidisciplinary studies on VGICs help researchers discover potential targets of VGICs and novel VGICs in heart, enrich their knowledge of the properties and functions, determine the operation mechanisms of pathological VGICs, and introduce groundbreaking trends in drug therapy strategies, and drug safety evaluation.

Out-of-hospital cardiac arrest and differential risk of cardiac and non-cardiac QT-prolonging drugs in 37 000 cases

Aims

Drugs that prolong the QT interval, either by design (cardiac QT‐prolonging drugs: anti‐arrhythmics) or as off‐target effect (non‐cardiac QT‐prolonging drugs), may increase the risk of ventricular arrhythmias and out‐of‐hospital cardiac arrest (OHCA). Risk mitigation measures were instituted, in particular, surrounding prescription of cardiac QT‐prolonging drugs. We studied OHCA risk of both drug types in current clinical practice.

Methods

Using data from large population‐based OHCA registries in the Netherlands and Denmark, we conducted two independent case–control studies. OHCA cases with presumed cardiac causes were matched on age/sex/index date with up to five non‐OHCA controls. We calculated odds ratios (ORs) for the association of cardiac or non‐cardiac QT‐prolonging drugs with OHCA risk using conditional logistic regression analyses.

Results

We identified 2503 OHCA cases and 10 543 non‐OHCA controls in the Netherlands, and 35 017 OHCA cases and 175 085 non‐OHCA controls in Denmark. Compared to no use of QT‐prolonging drugs, use of non‐cardiac QT‐prolonging drugs (Netherlands: cases: 3.0%, controls: 1.9%; Denmark: cases: 14.9%, controls: 7.5%) was associated with increased OHCA risk (Netherlands: OR 1.37 [95% CI: 1.03–1.81]; Denmark: OR 1.63 [95% CI: 1.57–1.70]). The association between cardiac QT‐prolonging drugs (Netherlands: cases: 4.0%, controls: 2.5%; Denmark: cases: 2.1%, controls: 0.9%) and OHCA was weaker (Netherlands: OR 1.17 [95% CI: 0.92–1.50]; Denmark: OR 1.21 [95% CI: 1.09–1.33]), although users of cardiac QT‐prolonging drugs had more medication use and comorbidities associated with OHCA risk than users of non‐cardiac QT‐prolonging drugs.

Conclusion

In clinical practice, cardiac QT‐prolonging drugs confer lower OHCA risk than non‐cardiac QT‐prolonging drugs, although users of the former have higher a priori risk. This is likely due to risk mitigation measures surrounding prescription of cardiac QT‐prolonging drugs.

Cisapride Use in Pediatric Patients With Intestinal Failure and Its Impact on Progression of Enteral Nutrition

OBJECTIVE

Gastrointestinal dysmotility is common in patients with pediatric intestinal failure (PIF), leading to delays in advancement of enteral nutrition (EN). Few studies have been published regarding the safety and efficacy of cisapride for improvement of enteral tolerance and ability to wean parenteral nutrition. Our objective was to describe a single center experience on the use of cisapride in patients with PIF.

METHODS

Retrospective chart review of patients was performed. Demographic, intestinal anatomy, and outcome data were collected. Percentage of EN before initiation of cisapride, progression of EN at 3 and 6 months, and ability to wean parenteral nutrition after initiation of cisapride were calculated.

RESULTS

Prokinetics were used in 61 of 106 patients (56.6%); 29 of 60 patients (48.3%) failed to progress EN on other prokinetics and started on cisapride. Before cisapride the progress of EN plateaued for a mean of 42.3 (standard deviation [SD] 60.2) days. The rate of feed progression was 0.14% (SD 0.19)/day pre-cisapride and 0.69%/day (SD 0.31) after cisapride initiation (P < 0.001). Percentage of EN improved significantly from baseline to 3 months postinitiation (23.9% vs 79.4%, respectively; P < 0.001). Electrocardiogram was performed on initiation of cisapride and after every dose change. Medication was discontinued in 2 of 29 (6.8%).

CONCLUSION

This retrospective study suggests that cisapride may be beneficial in PIF patients who fail to progress EN on first line prokinetics. The most significant period of improvement occurs within 3 months of cisapride initiation. Cardiac side effects in our cohort were lower than previously reported; however, cardiac monitoring is still recommended.

Drugs and life-threatening ventricular arrhythmia risk: results from the DARE study cohort

OBJECTIVES

To establish a unique sample of proarrhythmia cases, determine the characteristics of cases and estimate the contribution of individual drugs to the incidence of proarrhythmia within these cases.

SETTING

Suspected proarrhythmia cases were referred by cardiologists across England between 2003 and 2011. Information on demography, symptoms, prior medical and drug histories and data from hospital notes were collected.

PARTICIPANTS

Two expert cardiologists reviewed data for 293 referred cases: 130 were included. Inclusion criteria were new onset or exacerbation of pre-existing ventricular arrhythmias, QTc >500 ms, QTc >450 ms (men) or >470 ms (women) with cardiac syncope, all secondary to drug administration. Exclusion criteria were acute ischaemia and ischaemic polymorphic ventricular tachycardia at presentation, structural heart disease, consent withdrawn or deceased prior to study. Descriptive analysis of Caucasian cases (95% of included cases, n=124) and culpable drug exposures was performed.

RESULTS

Of the 124 Caucasian cases, 95 (77%) were QTc interval prolongation-related; mean age was 62 years (SD 15), and 63% were female. Cardiovascular comorbidities included hypertension (53%) and patient-reported 'heart rhythm problems' (73%). Family history of sudden death (36%) and hypokalaemia at presentation (27%) were common. 165 culpable drug exposures were reported, including antiarrhythmics (42%), of which amiodarone and flecainide were the most common. Sotalol, a beta-blocking agent with antiarrhythmic activity, was also common (15%). 26% reported multiple drugs, of which 84% reported at least one cytochrome (CYP) P450 inhibitor. Potential pharmacodynamics interactions identified were mainly QT prolongation (59%).

CONCLUSIONS

Antiarrhythmics, non-cardiac drugs and drug combinations were found to be culpable in a large cohort of 124 clinically validated proarrhythmia cases. Potential clinical factors that may warn the prescriber of potential proarrhythmia include older women, underlying cardiovascular comorbidity, family history of sudden death and hypokalaemia.

Preladenant, a selective adenosine A₂A receptor antagonist, is not associated with QT/QTc prolongation

PURPOSE

Preladenant is an orally administered adenosine2A (A2A) receptor antagonist in phase III development for Parkinson's disease treatment. This thorough QT/QTc study evaluated its potential effects on cardiac repolarization.

METHODS

This was a randomized, double-blind, positive- and placebo-controlled, four-period crossover study performed under steady-state exposure of clinical and supratherapeutic doses of preladenant (10 mg BID and 100 mg BID, respectively, for 5 days), moxifloxacin (400 mg on day 5), or placebo in 60 healthy adult volunteers. The potential effect on QTcF was measured by the largest upper bound of 95 % one-sided CIs for the mean changes from time-matched baseline ECG recordings compared with placebo. Plasma preladenant concentrations were also determined on day 5.

RESULTS

The QTcF difference for moxifloxacin compared with placebo exceeded 5 ms from 1 to 12 h postdose, establishing assay sensitivity. The QTcF interval was similar between the preladenant and placebo treatment groups: the upper bound of the 95 % one-sided CI for the mean difference in QTcF between preladenant and placebo was less than 10 ms at all time points for the supratherapeutic treatment group (1.3 to 5.7 ms, mean difference: -1.3 to 2.7 ms) and the therapeutic treatment group (0.4 to 4.3 ms, mean difference: -2.1 to 1.5 ms), substantially below the threshold of regulatory concern. The supratherapeutic dose (100 mg BID) provided a Cmax margin of 6.1-fold and AUC margin of 6.9-fold, respectively, compared with 10 mg BID.

CONCLUSIONS

At clinical and supratherapeutic doses, preladenant is not associated with QTc prolongation.

Pharmacological therapy of gastroesophageal reflux in preterm infants

Although gastroesophageal reflux (GER) is a very common phenomenon among preterm infants, its therapeutic management is still an issue of debate among neonatologists. A step-wise approach should be advisable, firstly promoting nonpharmacological interventions and limiting drugs to selected infants unresponsive to the conservative measures or who are suffering from severe GER with clinical complications. Despite of this, a concerning pharmacological overtreatment has been increasingly reported. Most of the antireflux drugs, however, have not been specifically assessed in preterm infants; moreover, serious adverse effects have been noticed in association to their administration. This review mainly aims to draw the state of the art regarding the pharmacological management of GER in preterm infants, analyzing the best piecies of evidence currently available on the most prescribed anti-reflux drugs. Although further trials are required, sodium alginate-based formulations might be considered promising; however, data regarding their safety are still limited. Few piecies of evidence on the efficacy of histamine-2 receptor blockers and proton pump inhibitors in preterm infants with GER are currently available. Nevertheless, a significantly increased risk of necrotizing enterocolitis and infections has been largely reported in association with their use, thereby leading to an unfavorable risk-benefit ratio. The efficacy of metoclopramide in GER's improvement still needs to be clarified. Other prokinetic agents, such as domperidone and erythromycin, have been reported to be ineffective, whereas cisapride has been withdrawn due to its remarkable cardiac adverse effects.

Cisapride improves enteral tolerance in pediatric short-bowel syndrome with dysmotility

BACKGROUND AND OBJECTIVES

Gastrointestinal dysmotility is common in pediatric short-bowel syndrome, leading to prolonged parenteral nutrition dependence. There is limited literature regarding the safety and efficacy of cisapride for this indication. The aim of the study was to describe the safety and efficacy of cisapride for enteral intolerance in pediatric short-bowel syndrome.

METHODS

Open-labeled pilot study in a limited access program for cisapride. Indications were short-bowel syndrome with underlying dysmotility and difficulty advancing enteral feeds despite standard therapies and without evidence of anatomic obstruction. Patients received cisapride 0.1 to 0.2 mg/kg per dose for 3 to 4 doses per day. We collected electrocardiogram, nutrition, and anthropometric data prospectively at study visits.

RESULTS

Ten patients with mean (SD) age of 30.3 (30.5) months were enrolled in our multidisciplinary pediatric intestinal rehabilitation program. Median (interquartile range [IQR]) duration of follow-up was 8.7 (3.1-14.3) months. Median (IQR) residual bowel length was 102 (85-130) cm. Median (IQR) citrulline level was 14.5 (10.5-31.3) μmol/L. Diagnoses included isolated gastroschisis (n = 3), gastroschisis with intestinal atresia (n = 4), necrotizing enterocolitis (n = 2), and long-segment Hirschsprung disease (n = 1). Six subjects had at least 1 prior bowel-lengthening procedure. Median (IQR) change in percentage enteral energy intake was 19.9% (15.4%-29.8%) during follow-up (P = 0.01). Seven patients improved in enteral tolerance during treatment and 2 were weaned completely from parenteral nutrition. Complications during therapy were prolonged corrected QT interval (n = 2), gastrointestinal bleeding (n = 2), D-lactic acidosis (n = 1), and death due to presumed sepsis (n = 1). Longitudinal analysis (general estimating equation model) showed a strong positive association between cisapride duration and improved enteral tolerance. Mean percentage of enteral intake increased by 2.9% for every month of cisapride treatment (P < 0.0001).

CONCLUSIONS

Cisapride is a potentially useful therapy in patients with pediatric short-bowel syndrome with gastrointestinal dysmotility. We observed modest improvement in feeding tolerance where prior treatments failed; however, patients treated with cisapride require careful cardiac monitoring because corrected QT prolongation occurred in 20% of our cohort.

Early life risk factors that contribute to irritable bowel syndrome in adults: a systematic review

BACKGROUND

Irritable bowel syndrome (IBS) is a common disorder that occurs in adults. The natural history of symptoms and risk factors that contribute to IBS may begin in childhood. The aim of this systematic review was to determine what early life factors contribute to the development of IBS in adolescents and adults.

METHODS

A computer-assisted search of the PubMed database from 1966 to 2007 was performed. The selection criteria were: (a) studies conducted in adolescents or adults with IBS that (b) investigate premorbid factors occurring specifically during the childhood period and are (c) associated with the outcomes of symptoms, quality of life, health-care utilization, and interferences with work or disability.

RESULTS

Twenty-five articles met inclusion criteria. The studies were categorized into articles examining the persistence of childhood gastrointestinal symptoms into adulthood, affluent childhood socioeconomic status and adult IBS, infantile and childhood trauma associated with the development of adult IBS, and social learning of illness behavior as predictors of adult IBS.

CONCLUSION

Pediatricians should be aware of potentially modifiable childhood risk factors and should consider interventions such as early symptom management of recurrent functional abdominal pain with cognitive therapies and parent education about social learning of illness behavior. Early treatment may have a long-term impact. Research examining the effect of affluent childhood socioeconomic status and early childhood trauma in the evolution of functional gastrointestinal disorders may help identify causative factors of IBS.

Autonomic tone attenuates drug-induced QT prolongation

INTRODUCTION

The QT interval is a predictor of sudden death. Many drugs prolong the QT, primarily through I(Kr) block. Autonomic tone directly affects heart rate and ventricular repolarization, but its effects in the setting of I(Kr) block are unknown.

OBJECTIVE

Determine the effects of autonomic tone on heart rate and QT interval after I(Kr) block.

METHODS AND RESULTS

Healthy adults (n = 9) were administered ibutilide with ECGs obtained at regular intervals. On a separate day, subjects were administered intravenous propranolol and atropine to induce autonomic block, resulting in intrinsic heart rate and QT interval; ibutilide was administered again, with serial ECGs obtained at regular intervals. No differences in baseline RR, QT, or QTc intervals were seen between the two study days. Ibutilide in the setting of intact autonomic tone prolonged QTc by 43 +/- 8 msec (P = 0.001) and prolonged RR interval by 93 +/- 39 msec (P = 0.04). Autonomic block alone on the second day prolonged QTc by 16.7 +/- 9.4 msec (P = 0.02). An additional 68 +/- 5 msec prolongation of QTc was seen with ibutilide in the setting of double autonomic block (P = 0.036). There was no effect of ibutilide on intrinsic heart rate (P = 0.125).

CONCLUSION

Autonomic block results in an exaggeration of drug-induced QT prolongation by ibutilide. I(Kr) block has no effect on intrinsic heart rate. QT-prolonging drugs may have more deleterious effects in those with underlying autonomic dysfunction, thus increasing the risk for sudden death.

Coadministration of scrtraline with cisapride or pimozide: an open-label, nonrandomized examination of pharmacokinetics and corrected qt intervals in healthy adult volunteers

BACKGROUND

Sertraline hydrochloride is a selective serotonin reuptake inhibitor with demonstrated efficacy and safety for the treatment of the following disorders: major depressive, obsessive-compulsive, panic, premenstrual dysphoric, social anxiety, and posttraumatic stress. Although sertraline is unlikely to cause clinically significant inhibition of cytochrome P450 (CYP) 3A4 substrates, even modest concentration increases for narrow therapeutic index drugs, such as pimozide or cisapride, are potentially important.

OBJECTIVE

The goal of this study was to determine whether there is a pharmacokinetic interaction, as shown by plasma concentrations and electrocardiographic evidence of QTc intervals, between sertraline 200 mg QD and cisapride 10 mg QID, and between sertraline 200 mg QD and pimozide (single 2-mg dose).

METHODS

Patients in group A were administered cisapride on days 1 and 2 (10 mg QID), day 3 (10 mg/d), days 25 through 29 (10 mg QID), and day 30 (10 mg/d). Sertraline was administered on days 4 through 29 at a starting dose of 50 mg/d, which was titrated upward in 50-mg increments every third day to a maximum of 200 mg/d. Patients in group B were treated with 2 mg of pimozide on days 1 and 39. Sertraline was administered on days 18 through 46 at a starting dose of 50 mg/d, which was titrated upward in 50-mg increments every third day to a maximum of 200 mg/d.

RESULTS

There were 9 males and 6 females in group A (sertraline + cisapride) (mean age, 34.4 years for males, 41.7 years for females; mean weight, 78.7 kg for males, 66.6 kg for females; 14 Hispanic, 1 white), and 8 males and 7 females in group B (sertraline + pimozide) (mean age, 26.1 years for males, 33.4 years for females; mean weight, 70.8 kg for males, 61.4 kg for females; 15 Hispanic). Coadministration of sertraline and cisapride resulted in statistically significant reductions of 29% and 36% in cisapride C(max) and AUC from time 0 to 6 hours, respectively, compared with cisapride alone. Coadministration of sertraline and pimozide resulted in statistically significant increases of 35% and 37% in pimozide Cmax and AUC(0-infinity), respectively, compared with pimozide alone. No subject exhibited a prolongation of the QTc interval > or =15% with coadministration of sertraline and cisapride, or sertraline and pimozide.

CONCLUSIONS

This study found that coadministration of sertraline with cisapride resulted in decreases in cisapride concentrations, and no significant effects on QTc intervals. Coadministration of sertraline 200 mg/d and a single dose of pimozide 2 mg produced significant increases in pimozide concentrations but no prolongation of the QTc interval > or =15%. This opposite effect for pimozide compared with cisapride, as well as other previously tested CYP3A4 substrates, suggests that there are mechanisms other than CYP3A4 involved in the sertraline-pimozide interaction.

Meta-analysis of randomized controlled trials on the benefits and risks of using cisapride for the treatment of gastroesophageal reflux in children

BACKGROUND AND AIM

Gastroesophageal reflux is a common problem in infancy. Cisapride is a commonly used therapy for gastroesophageal reflux in children. In view of recent concern regarding adverse effects this study aims to evaluate the benefits and risks of cisapride for the treatment of gastroesophageal reflux in children.

METHODS

A meta-analysis of randomized controlled trials of cisapride using a random-effects model.

RESULTS

Ten trials involving 415 children were identified. There was no evidence of a significant reduction in vomiting severity with cisapride as measured by a clinical score (five trials, standardized weighted mean difference -0.18; 95% confidence interval (CI) -0.51 to 0.15). Twenty-four-hour esophageal pH monitoring data showed the mean reflux index was significantly lower in the children treated with cisapride compared with controls (five trials, weighted mean difference -6.24; 95% CI -8.81 to -3.67). With cisapride treatment, there was no reduction in the mean number of reflux episodes lasting greater than 5 min (three trials, weighted mean difference -0.72; 95% CI -1.92 to 0.47) or in the number of children with esophagitis at final follow up compared with baseline (two trials, relative risk 0.80; 95% CI 0.40 to 1.61). There was no significant difference in reported side-effects or adverse events (six trials, relative risk 1.16; 95% CI 0.95 to 1.41).

CONCLUSIONS

No clinically important benefits of cisapride in children with gastroesophageal reflux have been demonstrated. Nor was there any evidence of adverse or harmful events.

The dog's role in the preclinical assessment of QT interval prolongation

During the development of a new therapeutic, few pharmacodyamic outcomes currently receive as much scrutiny as the effect of a potential medication on the electrocardiographic QT interval. The recent withdrawal from marketing of several drugs due to potential drug-related cardiac arrhythmias have greatly increased concern about drug-related changes on the QT interval. In order to reduce the incidence of these idiosyncratic episodes, regulatory agencies have suggested that sponsors use more rigorous methodology during the safety evaluation of new pharmaceuticals. Along with enhanced electrocardiographic assessments during clinical trials, advanced preclinical examinations of effect on QT interval and ventricular repolarization have become de rigueur. In this arena, the beagle dog is the preclinical species often associated with the most reliable predictivity for human safety assessment. To this end, canine models of cardiovascular safety assessment are discussed along with the relevance of these assays to human electrocardiography.

Comparison between pediatricians and family practitioners in the use of the prokinetic cisapride for gastroesophageal reflux disease in children

OBJECTIVE

The North American Society for Pediatric Gastroenterology, Hepatology and Nutrition and the European Society of Pediatric Gastroenterology, Hepatology and Nutrition have recently issued treatment guidelines for the use of cisapride in children. Our hypothesis was that cisapride is misused in the community and is not prescribed according to suggested recommendations. Therefore, the aim of this study was to evaluate the knowledge of pediatricians and family practitioners regarding the prescribing practice and adverse effects of cisapride.

METHODS

A standardized questionnaire was sent to a randomly selected group of pediatricians and family practitioners in Northern Israel. The questionnaire was designed to evaluate the knowledge of the physician regarding the treatment of gastroesophageal reflux disease and the use of cisapride in children (indications, dosages, duration of treatment, limitations in certain age groups, the need for pretreatment laboratory tests, interactions with other drugs, and contraindications). Replies were scored from 0 to 100 according to the treatment guidelines of both the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition and the European Society of Pediatric Gastroenterology, Hepatology and Nutrition. In addition, 2 questions dealt with the subjective efficacy of the drug and its adverse events.

RESULTS

The knowledge scores were 62% and 51% in the pediatricians and family practitioners, respectively. Other major findings were as follows: 1) 40% of pediatricians and 65% of family practitioners do not prescribe the recommended dose of cisapride, 2) 6% of pediatricians and 42% of family practitioners prescribe cisapride for infantile colic, 3) only 50% of pediatricians and 22% of family practitioners were aware of possible interactions with macrolides, and 4) only 31% of pediatricians and 54% of family practitioners were aware that cisapride might cause prolongation of the QT interval. Only minor adverse events were reported.

CONCLUSIONS

The knowledge of both pediatricians and family practitioners in the use of cisapride in children is suboptimal. It is essential to improve the education of community physicians to reduce the potential for adverse events arising from the misuse of this prokinetic agent.

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.

Efficacy and tolerability of cisapride in children

As gastro-oesophageal reflux disease (GORD) in infants and children is a motility disorder which differs in pathophysiology and clinical course from GORD in adults, prokinetics should be considered the drug of choice in certain circumstances. Indeed, cisapride may result in improvement of feeding tolerance in premature infants. Cisapride has a better tolerability profile than a 'wait-and-see-if-improvement-comes-spontaneously' policy or the other therapeutic options available. A careful and critical review of published data suggests that cisapride may have a QTc-prolonging effect. However, provided the precautions for cisapride administration are followed, the QTc-prolonging effect remains consistently without clinically relevant adverse effects. Correct dosage and avoidance of concurrent treatment with macrolides and/or azoles are the most relevant tolerability recommendations in children. Although there is a need for a prokinetic with better efficacy, cisapride is currently the prokinetic with the best benefit-to-risk ratio available. Thus, withdrawal of cisapride would result in a significantly increased risk for severe complications in infants and children with GORD or other gastrointestinal motility disorders such as chronic intestinal pseudo-obstruction, gastroparesis and feed intolerance in premature infants.

Cisapride does not prevent postoperative vomiting in children

The peripherally acting prokinetic drug cisapride can overcome opioid-induced gastrointestinal paresis and may thereby eliminate a stimulus for postoperative vomiting. We conducted a prospective, randomized, double-blinded, controlled trial of 96 children undergoing inguinal surgery to determine whether cisapride would reduce the incidence of postoperative vomiting after general anesthesia supplemented with morphine. Group C1 patients (n = 38) received cisapride 0.3 mg/kg orally 1 h before surgery and placebo 6 h later, Group C2 (n = 28) received cisapride both before and after surgery, and Group P (n = 30) received placebo. Mean age (5.0 +/- 2.7 yr) and weight (21.0 +/- 8.6 kg), median pain scores and parent satisfaction scores, and incidence of rescue analgesic administration were similar across groups. Contrary to our hypothesis, incidences of postoperative vomiting in the hospital (32% vs 20%, P = 0.33) and at home (53% vs 46%, P = 0.33) did not vary by treatment group (with [C1 and C2] and without [P] cisapride, respectively). There was a trend toward more severe postoperative vomiting (three or more episodes) in children who received cisapride versus those who did not, both in hospital (6% vs 0%, P = 0.3) and at home (22% vs 8%) (P = 0.13). We conclude that cisapride does not prevent postoperative vomiting in this patient population and speculate that factors other than reduced gastrointestinal motility associated with general anesthesia and opioids are more important determinants of postoperative vomiting.

IMPLICATIONS

Cisapride does not prevent postoperative vomiting in children and may increase its severity.

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.

The effect of cisapride on the corrected QT interval and QT dispersion in premature infants

BACKGROUND

Cisapride is used frequently in premature neonates as a gastrointestinal prokinetic drug. Concerns exist, however, about its safety because of its effect on the QT interval. Premature infants could be at higher risk for side effects because of their immaturity. This prospective study investigated the pharmacokinetics of cisapride and its effects on corrected QT interval (QTc) and QT dispersion in premature infants.

METHODS

Electrocardiogram examination was performed just before and after 72 hours of treatment with cisapride (0.2 mg/kg per dose, four times daily) in 10 premature infants. Trough and anticipated peak plasma level of cisapride and norcisapride were quantified after 72 hours of treatment. Results were compared with a cohort of 41 term infants aged 0 to 3 months receiving cisapride treatment.

RESULTS

The QTc interval increased significantly from 423 ms to 461 ms after 72 hours of treatment (P = 0.0007). No effect was seen on QT dispersion (44.3 ms vs. 45.9 ms). The change in QTc interval was inversely related to postnatal age (R2 = 0.52; P = 0.02), whereas there was no correlation with gestational age or plasma levels of cisapride or norcisapride. Trough and anticipated peak plasma levels of cisapride and norcisapride were significantly higher in the premature infants compared with the term infants aged 0 to 3 months (P < 0.001).

CONCLUSIONS

Premature infants less than 1 month of age could be at higher risk for cardiac side effects of cisapride when used in the same dosage as in older infants. The daily dose should be reduced (0.1 mg/kg per dose, maximum four times daily), and the QTc interval should be monitored closely. The benefits and safety of cisapride in premature infants less than 1 month of age should be reconsidered.

Cisapride plasma levels and corrected QT interval in infants undergoing routine polysomnography

BACKGROUND

Reported QTc prolongation associated with cardiac arrhythmia in a small number of children undergoing cisapride therapy and lack of pharmacokinetic correlation provided the impetus for this prospective study. The authors evaluated the relation between cisapride plasma concentrations, the electrocardiographic QT interval, and cardiac rhythm in infants undergoing routine 8-hour polysomnography.

METHODS

A total of 211 infants were enrolled: 84 (17 born prematurely) undergoing cisapride therapy for at least 4 days for suspected gastroesophageal reflux and 127 controls (10 born prematurely), aged between 1 week and 13.5 months. Infants underwent continuous bipolar limb lead I recording during routine 8-hour polysomnography. QT intervals and heart rate were measured at hourly intervals. The morning after polysomnography, 12-lead electrocardiography was performed (1 hour after cisapride administration). Cisapride plasma concentrations were determined immediately before and 1 to 2 hours after administration. Serum electrolyte concentrations were measured.

RESULTS

The administered cisapride dose ranged from 0.35 to 1.55 (mean, 0.81, median 0.79) mg. kg-1. d-1. Cisapride plasma concentrations were significantly higher in infants younger than 3 months of age. Cisapride-treated infants younger than 3 months of age had longer QTc intervals compared with age-matched controls. Heart rate was similar for cisapride-treated and control infants. No arrhythmia or atrioventricular conduction abnormalities were observed.

CONCLUSIONS

At comparable doses of cisapride and comparable plasma concentrations, the QTc was significantly higher in infants younger than 3 months of age. This confirms age-dependent cisapride pharmacokinetics in the first 10 to 12 weeks strongly correlated with changes in body weight and may also suggest an altered ability of infants younger than 3 months of age to metabolize cisapride. The clinical significance and risk of the increased QTc interval is unclear. Cisapride should be judiciously prescribed in infants younger than the age of 3 months and electrocardiography should be performed before and during therapy.

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.

Does cisapride influence cardiac rhythm? Results of a United States multicenter, double-blind, placebo-controlled pediatric study

BACKGROUND

Major concerns about serious cardiac side effects underlie the recent decision by the FDA and Janssen Pharmaceutica (Titusville, NJ) to make cisapride available only through a limited access program. Concerns have grown despite the fact that most instances of prolonged QTc and other ventricular arrhythmias occurred while the drug was used concomitantly with contraindicated drugs. This study sought to analyze electrocardiograms (ECGs) from a multicenter pediatric study and to identify abnormalities in QTc interval associated with cisapride use.

METHODS

Children between 6 months and 4 years of age were enrolled if they manifested symptoms of gastroesophageal reflux not responding to medical therapy for at least 6 weeks. In 49 subjects, ECGs obtained before and after randomization to receive 0.2 mg/kg dose three times daily or placebo were reviewed independently and blindly by two pediatric cardiologists. Placebo and active drug groups were compared for QTc and for change in QTc from baseline values after 3 to 8 weeks of treatment.

RESULTS

Mean QTc among patients taking the drug was 408+/-18 ms. None was higher than 450 ms. Change between baseline and subsequent QTc at 3 to 8 weeks of treatment was 2+/-20 ms.

CONCLUSIONS

In our study group of children without underlying cardiac disease or electrolyte imbalance, cisapride was found to have no significant effect on cardiac electrical function compared with placebo. These results are consistent with the drug's record of exceedingly infrequent cardiac events. Because the availability of this prokinetic is threatened, its safety and the safety and efficacy of alternative treatment options (including surgery) should be studied further.

Effects of cisapride on QTc interval in term neonates

BACKGROUND

Cisapride administration for 48 hours has been shown to increase heart rate corrected QT (QTc) interval in preterm neonates. Accumulation of the drug because of liver enzyme immaturity has been suggested to be the reason. If this is correct, a longer survey of QTc interval should disclose an increase even in term neonates.

OBJECTIVE

A prospective survey of the effects of cisapride on QTc interval in term neonates administered cisapride.

SETTING

Neonatal Unit of the University Hospital of Dijon, France.

DESIGN

QTc interval was determined just before and 48 hours, seven days, and 15 days after the start of treatment.

SUBJECTS

Twenty one term newborn infants (mean gestational age 39.3 weeks) given the recommended dose of cisapride (0.2 mg/kg, four times a day).

RESULTS

Administration of cisapride caused a significant increase in QTc interval (p < 0. 01). The mean value increased from 0.397 before treatment to 0.418 after 48 hours, 0.431 by day 7, and 0.447 by day 15. A QTc interval exceeding 0.450 was found in six neonates: three at 48 hours, one at day 7, and two at day 15. In two infants, withdrawal of the drug was associated with normalisation of the QTc interval.

CONCLUSIONS

These results support the hypothesis of cisapride accumulation in newborns due to enzymatic immaturity and indicate that QTc interval should be monitored in neonates receiving this drug.

Effects of cisapride on corrected QT interval, heart rate, and rhythm in infants undergoing polysomnography

OBJECTIVE

To evaluate the effects of cisapride, a prokinetic gastrointestinal drug, on the electrocardiographic QT interval, heart rate, and rhythm in infants during routine 8-hour polysomnography. Reported electrocardiogram (ECG) and rhythm disturbances in a small number of patients with the use of cisapride provided the impetus for this prospective study.

STUDY DESIGN

Two hundred fifty-two infants born at term were enrolled. Of these, 134 were on cisapride therapy for suspected gastroesophageal reflux and 118 were not on cisapride and served as controls. Cisapride-treated and control infants were from the outset divided into 3 age groups; group 1: under 3 months of age; group 2: between 3 and 6 months of age; and group 3: >6 months of age. Continuous ECG bipolar limb lead I recording, saturation monitoring, and electroencephalography were conducted. QT intervals and heart rate were measured at hourly intervals.

RESULTS

Cisapride doses were: group 1 mean, 0.80 mg/kg/day (range: 0.38-1.55); group 2 mean, 0.80 mg/kg/day (range: 0. 23-1.38); and group 3 mean, 0.72 mg/kg/day (range: 0.32-1.41). Heart rate was higher in the younger infants, with a gradual decrease with age. No difference in heart rate was detected between the cisapride and control groups. The QTc interval in patients in group 1 was statistically longer than the controls, when applying both Bazett's and Hodges' formulae for QT correction. The other age groups did not differ. No arrhythmia or atrioventricular conduction abnormalities were observed.

CONCLUSION

Infants under 3 months of age on cisapride treatment had significantly longer QTc intervals (with Bazett's formula, the 98th percentile was 504 ms in the cisapride group vs 447 ms in controls). The clinical significance and risk of the increased QTc interval in these infants are unclear and need further evaluation and risk stratification. Meanwhile, cisapride should be judiciously prescribed in infants <3 months of age.

Cisapride and QTc interval in children

BACKGROUND

Recent reports about cisapride have raised some concerns about the safety and efficacy of this medication in children. The aim of this study was to identify electrocardiographic changes and a predisposition to develop arrhythmias in children.

METHODS

Patients were divided in 2 groups: 1) 63 children (mean age: 29 months) who received cisapride (0.2 mg/kg/dose 3 times/day), and 2) 57 children (mean age: 27 months) who did not receive cisapride (they served as controls). Both groups did not have any associated disease. Electrocardiogram (EKG) was performed to children when they were included in the study. The QT interval was corrected using Bazett's formula. Twenty-four-hour Holter recording was performed in children with prolonged QT interval (PQTI). When PQTI was identified in group 1, cisapride was discontinued and a new EKG was performed.

RESULTS

Five children from group 1 and 6 from group 2 had PQTI. In 3 children with PQTI, the QTc interval returned to normal values when cisapride was discontinued. In children under 4 months of age, a statistical difference was found, with QTc interval being longer in group 2 (without cisapride) than in group 1. Holter recordings were normal in all children with PQTI.

CONCLUSION

PQTI can be found in normal children with or without cisapride. In our study PQTI was not associated with any life-threatening event.

Drug interactions with cisapride: clinical implications

Cisapride, a prokinetic agent, has been used for the treatment of a number of gastrointestinal disorders, particularly gastro-oesophageal reflux disease in adults and children. Since 1993, 341 cases of ventricular arrhythmias, including 80 deaths, have been reported to the US Food and Drug Administration. Marketing of the drug has now been discontinued in the US; however, it is still available under a limited-access protocol. Knowledge of the risk factors for cisapride-associated arrhythmias will be essential for its continued use in those patients who meet the eligibility criteria. This review summarises the published literature on the pharmacokinetic and pharmacodynamic interactions of cisapride with concomitantly administered drugs, providing clinicians with practical recommendations for avoiding these potentially fatal events. Pharmacokinetic interactions with cisapride involve inhibition of cytochrome P450 (CYP) 3A4, the primary mode of elimination of cisapride, thereby increasing plasma concentrations of the drug. The macrolide antibacterials clarithromycin, erythromycin and troleandomycin are inhibitors of CYP3A4 and should not be used in conjunction with cisapride. Azithromycin is an alternative. Similarly, azole antifungal agents such as fluconazole, itraconazole and ketoconazole are CYP3A4 inhibitors and their concomitant use with cisapride should be avoided. Of the antidepressants nefazodone and fluvoxamine should be avoided with cisapride. Data with fluoxetine is controversial, we favour the avoidance of its use. Citalopram, paroxetine and sertraline are alternatives. The HIV protease inhibitors amprenavir, indinavir, nelfinavir, ritonavir and saquinavir inhibit CYP3A4. Clinical experience with cisapride is lacking but avoidance with all protease inhibitors is recommended, although saquinavir is thought to have clinically insignificant effects on CYP3A4. Delavirdine is also a CYP3A4 inhibitor and should be avoided with cisapride. We also recommend avoiding coadministration of cisapride with amiodarone, cimetidine (alternatives are famotidine, nizatidine, ranitidine or one of the proton pump inhibitors), diltiazem and verapamil (the dihydropyridine calcium antagonists are alternatives), grapefruit juice, isoniazid, metronidazole, quinine, quinupristin/dalfopristin and zileuton (montelukast is an alternative). Pharmacodynamic interactions with cisapride involve drugs that have the potential to have additive effects on the QT interval. We do not recommend use of cisapride with class Ia and III antiarrhythmic drugs or with adenosine, bepridil, cyclobenzaprine, droperidol, haloperidol, nifedipine (immediate release), phenothiazine antipsychotics, tricyclic and tetracyclic antidepressants or vasopressin. Vigilance is advised if anthracyclines, cotrimoxazole (trimethoprim-sulfamethoxazole), enflurane, halothane, isoflurane, pentamidine or probucol are used with cisapride. In addition, uncorrected electrolyte disturbances induced by diuretics may increase the risk of torsade de pointes. Patients receiving cisapride should be promptly treated for electrolyte disturbances.

The assessment of potential for QT interval prolongation with new pharmaceuticals: impact on drug development

Few examinations of a single physiological variable can end the development of a putative new pharmaceutical. Prolongation of the electrocardiographic QT interval is one of these tests. Recognizing the removal of several approved and widely used medicines, worldwide regulatory authorities have raised a heightened awareness on the submission of data surrounding the ventricular repolarization process. This review will discuss the anatomy and physiology surrounding the generation of the electrocardiographic QT interval and the consequences of its alteration. In addition, relevant models of preclinical safety and general guidelines for clinical examination in this area are discussed along with the impact of incorporating these assays into the drug development process.

Review article: cardiac adverse effects of gastrointestinal prokinetics

Gastrointestinal prokinetics, such as metoclopramide, cisapride and levosulpiride, are widely used for the management of functional gut disorders. Recently, several studies have shown that cisapride (a partial 5-HT4 receptor agonist) can induce dose-dependent cardiac adverse effects, including lengthening of the electrocardiographic QT interval, syncopal episodes and ventricular dysrhythmias. Until recently, it was not clear whether these effects were dependent on 5-HT4 receptor activation or related to peculiar characteristics in the molecular structure of single agents within the benzamide class. Experimental evidence now favours the second hypothesis: cisapride possesses Class III antiarrhythmic properties and prolongs the action potential duration through blockade of distinct voltage-dependent K+ channels, thus delaying cardiac repolarization and prolonging the QT interval. Patients at risk of cardiac adverse effects are children, subjects with idiopathic, congenital or acquired long QT syndrome and, in particular, those receiving concomitant medication with Class III antiarrhythmic agents, some H1-receptor antagonists (e.g. terfenadine), or drugs such as azole antifungals (e.g. ketoconazole, itraconazole, miconazole and fluconazole) and macrolide antibacterials (e.g. erythromycin, clarithrod-mycin and troleandomycin), which can inhibit cisapride metabolism by interfering with the CYP3A4 isoenzyme.

Advances in the treatment of cardiac rhythm disturbances

Many advances in the care of children with cardiac rhythm disturbances have been made in the past year. From the fetus with supraventricular tachycardia to the adolescent with vasovagal syncope, new and effective therapies have evolved. Molecular genetics has led to monumental leaps in the understanding of long QT syndrome, and a new pharmacologic alternative to cardioversion has been introduced. There have also been new and noteworthy developments in the more established area of radiofrequency ablation. These concern safety and also touch on one of today's most controversial areas, cost effectiveness. This article discusses each of these advances in the realm of pediatric cardiac electrophysiology.

The role of cisapride in the treatment of pediatric gastroesophageal reflux. The European Society of Paediatric Gastroenterology, Hepatology and Nutrition

BACKGROUND

Cisapride is a gastrointestinal prokinetic agent that is used worldwide in the treatment of gastrointestinal motility-related disorders in premature infants, full-term infants, and children. Efficacy data suggest that it is the most effective commercially available prokinetic drug.

METHODS

Because of recent concerns about safety, a critical and in-depth analysis of all reported adverse events was performed and resulted in the conclusions and recommendations that follow.

RESULTS

Cisapride should only be administered to patients in whom the use of prokinetics is justified according to current medical knowledge. If cisapride is given to pediatric patients who can be considered healthy except for their gastrointestinal motility disorder, and the maximum dose does not exceed 0.8 mg/kg per day in 3 to 4 administrations of 0.2 mg/kg (not exceeding 40 mg/d), no special safety procedures regarding potential cardiac adverse events are recommended. However, if cisapride is prescribed for patients who are known to be or are suspected of being at increased risk for drug-associated increases in QTc interval, certain precautions are advisable. Such patients include those:(1) with a previous history of cardiac dysrhythmias, (2) receiving drugs known to inhibit the metabolism of cisapride and/or adversely affect ventricular repolarisation, (3) with immaturity and/or disease causing reduced cytochrome P450 3A4 activity, or (4) with electrolyte disturbances. In such patients, ECG monitoring to quantitate the QTc interval should be used before initiation of therapy and after 3 days of treatment to ascertain whether a cisapride-induced cardiac adverse effect is present.

CONCLUSIONS

With rare exceptions, the total daily dose of cisapride should not exceed 0.8 mg/kg divided into 3 or 4 approximately equally spaced doses. If higher doses than this are given, the precautions above are advisable. In any patient in whom a prolonged QTc interval is found, the dose of cisapride should be reduced or the drug discontinued until the ECG normalizes. If the QTc interval returns to normal after withdrawal of cisapride, and the administration of cisapride is considered to be justified because of its efficacy and absence of alternative treatment options, cisapride can be restarted at half dose with control of the QTc interval. Unfortunately, at present, normal ranges of QTc interval in children are unknown. However, a critical analysis of the literature suggests that a duration of less than 450 milliseconds can be considered to be within the normal range and greater than 470 milliseconds as outside it.