Coprescribing and codispensing of cisapride and contraindicated drugs

Tegaserod: What's Old Is New Again

Irritable bowel syndrome with constipation (IBS-C) and chronic idiopathic constipation (CIC) are common gastrointestinal disorders imposing considerable impact on the quality of life and well-being of affected individuals. A paucity of evidence-based treatment options exist for CIC and IBS-C sufferers. Tegaserod, a 5-HT₄ agonist, has a substantial body of preclinical and clinical study evidence to support its beneficial role in modulating sensorimotor function of the luminal gastrointestinal tract. Tegaserod was first approved for use by the U.S. Food and Drug Administration for the management of IBS-C and CIC in 2002 and 2004, respectively. Tegaserod enjoyed a successful uptake in the management of these disorders during its first several years of availability in the United States, but was later withdrawn from the market in 2007 over concerns related to adverse cardiovascular events. Since then, additional safety data has been generated, and following a resubmission and review by the Food and Drug Administration, in April 2019, tegaserod was once again approved for use in IBS-C under a more restricted labeling, confining use to women under 65 years of age without heart disease or additional cardiovascular risk factors. This review summarizes the regulatory journey of tegaserod and details the existing pharmacokinetic, physiologic, clinical, and safety data of tegaserod generated over the last 2 decades. The discussion also examines the future of tegaserod in the treatment of these constipation disorders, as well as its potential role in other related disorders of brain-gut interaction.

The Use of Real-World Data to Assess the Impact of Safety-Related Regulatory Interventions

The regulation of medicines seeks to ensure the efficacy, safety, and quality of prescription and non-prescription medicines. Given that the conditions under which a medicine's benefits outweigh its risks are complex, it is essential that communications about the safe and effective use of medicines be clear and actionable. Assessing the impact of interventions to improve the safe and effective use of medicines is a developing area, and one in which real-world data are playing an increasingly important role. Although real-world data are commonly used to assess the impact of regulatory interventions, there are several areas where their use could be improved. Specific areas for improvement include assessing regulatory interventions across a wider range of medicines, rather than concentrating on a relatively few therapeutic areas; assessing more clinically relevant outcomes rather than relying on measures such as changes in the number of prescriptions, which may not always correlate with the desired impact; assessing the potential unintended or negative consequences of regulatory interventions; applying methods to address potential confounders; assessing long-term, rather than just short-term, impacts of an intervention; increasing the use of comparator groups, when feasible; and evaluating the impact of regulatory interventions from multiple dimensions, rather than from a single dimension. Expanded use of real-world data could inform some of these efforts, although data sources beyond administrative claims data will likely be necessary to achieve all these goals.

Cardiovascular safety of prokinetic agents: A focus on drug-induced arrhythmias

BACKGROUND

Gastrointestinal sensorimotor dysfunction underlies a wide range of esophageal, gastric, and intestinal motility and functional disorders that collectively constitute nearly half of all referrals to gastroenterologists. As a result, substantial effort has been dedicated toward the development of prokinetic agents intended to augment or restore normal gastrointestinal motility. However, the use of several clinically efficacious gastroprokinetic agents, such as cisapride, domperidone, erythromycin, and tegaserod, is associated with unfavorable cardiovascular safety profiles, leading to restrictions in their use.

PURPOSE

The purpose of this review is to detail the cellular and molecular mechanisms that lead commonly to drug-induced cardiac arrhythmias, specifically drug-induced long QT syndrome, torsades de pointes, and ventricular fibrillation, to examine the cardiovascular safety profiles of several classes of prokinetic agents currently in clinical use, and to explore potential strategies by which the risk of drug-induced cardiac arrhythmia associated with prokinetic agents and other QT interval prolonging medications can be mitigated successfully.

Prescribing pattern of anti-Parkinson drugs in Japan: a trend analysis from 2005 to 2010

Objective

Therapeutic options for Parkinson's disease mainly consist of L-dopa and dopamine agonists. However, in Japan, the product labeling of the ergot dopamine agonists, cabergoline and pergolide, was revised in April 2007 due to the risk of developing cardiac valvulopathy. Here, we describe the prescribing trends of anti-Parkinson drugs from 2005 through 2010 in Japan, and examined whether these trends changed after the drug safety measures in 2007.

Methods and Patients

We used medical claim data from January 2005 to December 2010 for Parkinson's disease patients older than 30 years who were prescribed anti-Parkinson drugs. We calculated the proportion of patients prescribed each drug for each year, and compared the proportions of first-line drugs prescribed before and after April 2007. We also examined the prescription variations of cabergoline/pergolide users one year before or after April 2007.

Results

L-dopa was the most frequently prescribed drug for Parkinson's disease (2005, 58%; 2010, 51%). The proportion of patients prescribed ergot dopamine agonists markedly decreased and non-ergot dopamine agonists increased after 2007. Among first-line drugs, the proportion of non-ergot agents increased after April 2007. Among 54 cabergoline/pergolide users, 24 (44%) discontinued these drugs, nine of whom switched to non-ergot agents.

Conclusion

L-dopa was the mainstay of Parkinson's disease treatment between 2005 and 2010 in Japan. There was a decrease in ergot agents and an increase in non-ergot agents prescribed after the regulatory actions in 2007.

Methodological gaps in the assessment of risk minimization interventions: a systematic review

INTRODUCTION

Since the introduction of therapeutic risk management regulatory guidance, an increase in the number of risk minimization interventions (RMIs) published in the literature has been observed. Methods used to evaluate their effectiveness remain, however, poorly examined.

OBJECTIVE

This paper aimed to conduct a literature review on the methods of evaluation of effectiveness of RMIs and to identify methodological gaps.

METHODS

The search was conducted using MEDLINE and Embase between 1 January 2000 and 31 December 2010, and updated on 1 April 2013. The following characteristics were extracted from each study: target population for the RMI, target population for the assessment of effectiveness, study design, data sources, and effectiveness outcome(s).

RESULTS

A total of 188 unique RMIs were identified in the literature, of which effectiveness was evaluated in only 65 (34.6%) at the time of publication. The largest proportion of studies reviewed (n = 49, 75.4%) attempted to evaluate changes in behavior through prescribing or laboratory test practices. One quarter of studies evaluated the effect of RMIs on the occurrence of adverse events. Only a minority of studies used robust designs, such as randomized controlled trials (n = 6, 9.2%) or a quasi-experimental design with a parallel comparison group (n = 8, 12.3%).

CONCLUSION

Lack of robust methodological design used in published studies on RMI effectiveness evaluation is an important methodological gap in the evaluation of RMI effectiveness. © 2014 The Authors. Pharmacoepidemiology and Drug Safety published by John Wiley & Sons, Ltd.

When direct health-care professional communications have an impact on inappropriate and unsafe use of medicines

Serious safety issues relating to drugs are communicated to health-care professionals via Direct Health-Care Professional Communications (DHPCs). We explored which characteristics determined the impact of DHPCs issued in the Netherlands for ambulatory-care drugs (2001-2008). With multiple linear regression, we examined the impact on the relative change in new drug use post-DHPC of the following: time to DHPC, trend in use, degree of innovation, specialist drug, first/repeated DHPC, DHPC template, and type of safety issue. DHPCs have less impact on use of specialist drugs than nonspecialist drugs (P < 0.05). The DHPCs' impact increased after availability of a template emphasizing the main problem (P < 0.05), and for safety issues with a risk of death and/or disability (both P < 0.05) (adjusted R² = 0.392). Risk communication can be effective, specifically in case of well-structured information, and very serious safety issues. Effectiveness may improve by tailoring DHPCs and adding other communication channels, for example for drugs that are increasingly being used.

Systematic review: cardiovascular safety profile of 5-HT(4) agonists developed for gastrointestinal disorders

BACKGROUND

The nonselective 5-HT(4) receptor agonists, cisapride and tegaserod have been associated with cardiovascular adverse events (AEs).

AIM

To perform a systematic review of the safety profile, particularly cardiovascular, of 5-HT(4) agonists developed for gastrointestinal disorders, and a nonsystematic summary of their pharmacology and clinical efficacy.

METHODS

Articles reporting data on cisapride, clebopride, prucalopride, mosapride, renzapride, tegaserod, TD-5108 (velusetrag) and ATI-7505 (naronapride) were identified through a systematic search of the Cochrane Library, Medline, Embase and Toxfile. Abstracts from UEGW 2006-2008 and DDW 2008-2010 were searched for these drug names, and pharmaceutical companies approached to provide unpublished data.

RESULTS

Retrieved articles on pharmacokinetics, human pharmacodynamics and clinical data with these 5-HT(4) agonists, are reviewed and summarised nonsystematically. Articles relating to cardiac safety and tolerability of these agents, including any relevant case reports, are reported systematically. Two nonselective 5-HT(4) agonists had reports of cardiovascular AEs: cisapride (QT prolongation) and tegaserod (ischaemia). Interactions with, respectively, the hERG cardiac potassium channel and 5-HT(1) receptor subtypes have been suggested to account for these effects. No cardiovascular safety concerns were reported for the newer, selective 5-HT(4) agonists prucalopride, velusetrag, naronapride, or for nonselective 5-HT(4) agonists with no hERG or 5-HT(1) affinity (renzapride, clebopride, mosapride).

CONCLUSIONS

5-HT(4) agonists for GI disorders differ in chemical structure and selectivity for 5-HT(4) receptors. Selectivity for 5-HT(4) over non-5-HT(4) receptors may influence the agent's safety and overall risk-benefit profile. Based on available evidence, highly selective 5-HT(4) agonists may offer improved safety to treat patients with impaired GI motility.

Critical drug-drug interactions for use in electronic health records systems with computerized physician order entry: review of leading approaches

Medications represent the most common intervention in health care, despite their benefits; they also lead to an estimated 1.5 million adverse drug events and tens of thousands of hospital admissions each year. Although some are not preventable given what is known today, many types are, and one key cause which is preventable is drug-drug interactions (DDIs). Most electronic health record systems include programs that can check and prevent these types of interactions as a routine part of medication ordering. Studies suggest that these systems as implemented often do not effectively screen for these DDIs. A major reason for this deficiency is the lack of any national standard for the critical DDIs that should be routinely operationlized in these complex systems. We review the leading critical DDI lists from multiple sources including several leading health systems, a leading commercial content provider, the Leapfrog CPOE Testing Standard, and the new Office of the National Coordinator (ONC) DDI List. Implementation of strong DDI checking is one of the important steps in terms of realizing the benefits of electronic prescribing with respect to safety. Hopefully, the ONC list will make it easier for organizations to ensure they are including the most important interactions, and the Leapfrog List may help these organizations develop an operational DDI list that can be practically implemented. In addition, this review has identified 7 common DDIs that can be the starting point for all organizations in this area of medication safety.

Cisapride: what can we learn from the rise and fall of a prokinetic?

Cisapride, the prototype serotonergic agent, evolved from a body of research that defined the key roles of serotonergic receptors in gastrointestinal motor and sensory function. Impressed by its in vitro properties and encouraged by clinical trial data, cisapride became the drug of choice for the treatment of a wide range of motility disorders and clinicians appeared impressed by its efficacy and comfortable with its side-effect profile. Once serious cardiac events began to be reported in association with cisapride therapy, dark clouds rapidly gathered and soon enveloped the drug, leading to its widespread withdrawal from markets. What lessons can we learn from the story of cisapride? How can its brief but spectacular rise and equally sensational demise inform the development of new drugs which are so sorely needed in the management of motility and functional gastrointestinal disorders? This review explores the background to the development of cisapride, its history in clinical trials and the experience with adverse events and, in so doing, attempts to identify lessons for the future in the therapeutics of enteric neuromodulatory drugs.

Relevance of a "Dear Doctor letter" to alert healthcare providers to new recommendations for vitamin D administration

PURPOSE

After reports of malaise in infants immediately after the oral administration of two brands of vitamin D solutions, a "Dear Doctor letter" (DDL) containing recommendations for the administration of vitamin D was sent to all French paediatricians and pharmacies and a large number of French general practitioners (GPs) with a predominantly paediatric practice. The DDL and a press release were published on the French Medicines Agency website and distributed via a mailing list. The objective of this study was to assess the effectiveness of such a DDL and to collect the opinions of healthcare professionals on the best way to provide them with information.

METHODS

A questionnaire was sent to a national random sample of 145 paediatricians, 680 GPs and 230 pharmacists.

RESULTS

Only 49% of responding paediatricians, 48% of GPs and 67% of pharmacists were aware of the warning. Among the participating healthcare professionals aware of the warning and who prescribed/dispensed these vitamins, 50% of paediatricians and 68% of GPs stated that they had changed their prescribing behaviour, and 68% of pharmacists stated that they had modified their advice when dispensing. According to the responding healthcare professionals, postal letters remained the best way to issue safety warnings. Some of the respondents suggested that the DDL be more distinctive in terms of being a DDL and that the information be more widely disseminated to other stakeholders involved in the healthcare system.

CONCLUSIONS

This survey of a national random sample of healthcare professionals revealed that many of the respondents paid little attention to the DDL and were therefore unlikely to change their practices. A potential supplementary method for disseminating recommendations for medicine administration could be to apply stickers on medicine boxes, as this approach has the additional advantage of directly informing the concerned population, i.e. the parents.

Echocardiography for the detection of valvulopathy associated with the use of ergot-derived dopamine agonists in patients with Parkinson's disease

OBJECTIVE

The ergot-derived dopamine agonists, cabergoline and pergolide, are associated with valvulopathy risk. In Japan, product labels were revised in April 2007 to recommend periodic echocardiography for patients taking these dopamine agonists, however, the compliance of physicians to follow through with this recommendation is unknown. This study assessed changes in echocardiography evaluation of patients with Parkinson's disease (PD) taking cabergoline or pergolide before and after the label revision and examined the factors related with echocardiography performance.

METHODS AND PATIENTS

Medical claim data from January 2005 to December 2008 were used. Patients were divided into a C-P group (prescribed either cabergoline or pergolide) or reference group (prescribed other anti-PD drugs), and further classified based on whether they were prescribed these drugs "pre-revision" or "post-revision." The Cochran-Armitage trend test was used to compare the proportion of echocardiograms obtained amongst these groups before and after the revision. The frequencies of echocardiograms performed among the treatment groups for each period were compared by Fisher's exact test.

RESULTS

A total of 222 subjects (C-P, 73; reference, 149) were assessed. The proportion of C-P patients undergoing echocardiography increased from 4.8% to 27.9% after revision of product labels (p=0.001), which was higher than those in the reference group following label revisions (11.0%) (p=0.014). Prescription duration of C-P after the revision was longer in the patients with echocardiography than without echocardiography (p=0.026).

CONCLUSION

Although echocardiography evaluations increased, more than 70% of PD patients prescribed cabergoline or pergolide did not undergo such assessment despite the product label recommendation. Adherence to drug safety recommendations should be facilitated with more feasible and effective measures.

Deaths involving contraindicated and inappropriate combinations of serotonergic drugs

In the Australian state of Victoria, all fatalities that were recorded from 2002 through to 2008 involving the use of certain serotonin active drugs (tramadol, venlafaxine, fluoxetine, sertraline, citalopram and paroxetine), were reviewed to assess the incidence of contraindicated or ill advised drug combinations. More than 1,000 were identified of which 326 cases formed the basis of this study. These cases involved contraindicated or inappropriate drug combinations that can lead to adverse drug reactions (ADRs) and subsequent fatal toxicity. Of these, 46% were drug-related, 35% were a result of natural disease and 13% were classified as external injury cases. The remaining cases were those where the cause of death (COD) was unascertained. Tramadol was the most common drug, usually detected alongside a serotonergic antidepressant (in 20% of cases). Twenty-five (8%) cases involved contraindicated drug combinations while the remainder (301 cases, 92%) involved drug combinations that are associated with adverse interactions ranging from minor to major severity. Of these 326 cases, the Coroner determined 166 cases (51%) to be acts of intentional self-harm or drug misuse, with the remainder unascertained or attributed to natural disease. Very few post-mortem reports and Coroners' findings made mention of possible ADRs when such combinations were actually present. The majority of cases comprising contraindicated drug combinations involved the combined use of five drugs (24%) at the time of death. A combination of three to five drugs was most common in cases involving inadvisable drug combinations. Combined drug toxicity was the most common COD, with heart disease the most common co-morbidity.

SANDS: a service-oriented architecture for clinical decision support in a National Health Information Network

In this paper, we describe and evaluate a new distributed architecture for clinical decision support called SANDS (Service-oriented Architecture for NHIN Decision Support), which leverages current health information exchange efforts and is based on the principles of a service-oriented architecture. The architecture allows disparate clinical information systems and clinical decision support systems to be seamlessly integrated over a network according to a set of interfaces and protocols described in this paper. The architecture described is fully defined and developed, and six use cases have been developed and tested using a prototype electronic health record which links to one of the existing prototype National Health Information Networks (NHIN): drug interaction checking, syndromic surveillance, diagnostic decision support, inappropriate prescribing in older adults, information at the point of care and a simple personal health record. Some of these use cases utilize existing decision support systems, which are either commercially or freely available at present, and developed outside of the SANDS project, while other use cases are based on decision support systems developed specifically for the project. Open source code for many of these components is available, and an open source reference parser is also available for comparison and testing of other clinical information systems and clinical decision support systems that wish to implement the SANDS architecture. The SANDS architecture for decision support has several significant advantages over other architectures for clinical decision support. The most salient of these are:

The Prokinetic Cinitapride Has No Clinically Relevant Pharmacokinetic Interaction and Effect on QT during Coadministration with Ketoconazole

The present clinical trial was designed to evaluate the possible pharmacokinetic and electrocardiographic interactions of the gastroenteric prokinetic drug cinitapride with ketoconazole. The safety and tolerability of the study treatments were also evaluated. After a placebo-controlled, double-blind, crossover design, 16 healthy male (n = 8) and female (n = 8) volunteers were randomized into four treatment groups of four subjects (two males and two females): cinitapride (CTP; 1 mg t.i.d.) + ketoconazole (KET; 200 mg b.i.d.), CTP + placebo (PL), PL+KET, and PL+PL. Treatments were given for 7 days with a washout period of 14 days between crossover treatments. Cinitapride is rapidly absorbed after oral administration and is metabolized by the cytochrome P450 CYP3A4 and CYP2C8 isozymes. At steady state, coadministration with ketoconazole, a potent CYP3A4 inhibitor, increased mean C(max,ss) and AUC(tau) by 1.63- and 1.98-fold, respectively. Measurement of mean QTc interval or baseline-corrected QTc intervals on day 7 showed small increases that were due to the effects of ketoconazole alone. Comparing CTP+KET versus PL+KET, the differences between mean increases in the QTc parameters were always less than 2 ms. Finally, no outlier increase of the QTc interval versus baseline >60 ms was identified after any treatment. The study showed that cinitapride, either given alone or after coadministration with ketoconazole 200 mg b.i.d., had no effect on cardiac repolarization as measured by changes in the heart rate-corrected QT interval on the surface electrocardiogram.

Increase in mortality rate following coprescription of cisapride and contraindicated drugs

BACKGROUND

No epidemiologic study, as of this writing, has been published on the use of cisapride with contraindicated drugs and its relation to mortality rates in a population-based setting.

OBJECTIVE

To estimate the prevalence of concomitant use of cisapride with contraindicated drugs and evaluate the association between this and the risk of mortality.

METHODS

Claims data were obtained from the Health Insurance Review Agency of Korea. The study population consisted of patients younger than 85 years who visited clinics or hospitals in the city of Busan as new users of cisapride between November 1, 2000, and April 30, 2002. The coprescription of cisapride was defined as prescribing cisapride with one or more contraindicated drugs with the same prescription. Nationwide mortality data were also used. The prevalence of coprescribing cisapride was estimated and the association between this and the risk of mortality was assessed by rate ratios (RRs). The RRs were estimated using Cox's regression model with time-dependent covariate, adjusted for age, sex, and comorbidities.

RESULTS

A total of 36,865 patients out of 56,012 claims were newly prescribed cisapride; of these, 1175 patients (3.2%) were concomitantly prescribed at least one contraindicated drug, which suggested adjusted mortality RRs of 14.08 (95% CI 7.41 to 26.76) for recent users and 1.33 (95% CI 0.92 to 1.93) for past users of cisapride.

CONCLUSIONS

Despite the discontinuation of the drug's commercial marketing, cisapride was still in use in clinics and hospitals in Busan. In many cases, cisapride was co-prescribed with contraindicated drugs, which is associated with increased mortality rates.

Application of the Bradford Hill Criteria to Assess the Causality of Cisapride-Induced Arrhythmia

INTRODUCTION

The Bradford Hill criteria are a widely used, useful tool for the assessment of biomedical causation. We have examined their application to pharmacovigilance using the example of cisapride-induced QTc interval prolongation/arrhythmia.

METHODS

A literature search was conducted using MEDLINE, EMBASE, Reactions Weekly and regulatory websites to identify evidence for the association between cisapride and QTc interval prolongation/arrhythmia that had been published in the English language. Two hundred and five publications were identified as being potentially suitable for the study. After excluding irrelevant articles, studies on high-risk populations and review articles, 70 publications were assessed using the Bradford Hill criteria. These included 24 case reports, case series or spontaneous report summaries; eight epidemiological studies; 22 clinical studies; and 16 experimental (in vivo and in vitro) publications.

RESULTS

The most compelling evidence for an association between cisapride use and QTc interval prolongation/arrhythmia came from case/spontaneous reports and biological plausibility. Considering the rare incidence of serious cardiac events, these criteria formed the basis for the strength of the association. The number of reports from different populations showed consistency. Specificity was supported by clinical and cardiographic characterisation of the events. There were temporal relationships between the events and the initiation of cisapride treatment, increases in the dosage and the receipt of interacting medications. The relationships between the adverse events and the latter two factors exhibited biological gradients. Experimental evidence could be found from biological models, as well as reports of positive dechallenge and/or rechallenge found in individual patients. Cisapride was found to bind the human ether-a-go-go-related gene (HERG) potassium channel, which provides a plausible mechanism for QTc interval prolongation/arrhythmia. Other QTc interval-prolonging/arrhythmic drugs that also bind to HERG provided an analogy for cisapride causing QTc interval prolongation/arrhythmia via this mechanism. The evidence provided by clinical studies was inconsistent, and epidemiological studies failed to demonstrate an association. Nevertheless, this did not prevent the assessment of causation.

DISCUSSION

This study showed how different types of evidence found in pharmacovigilance can be evaluated using the Bradford Hill criteria. Further work is required to examine how the criteria can be applied to different types of adverse events and how they may be applied to pharmacovigilance.

Exploring the utility of automated drug alerts in home healthcare

Computerized drug utilization review (DUR) can potentially reduce adverse drug events. We examined automated DUR for home healthcare patients with diabetes or hypertension. Sixty-eight percent of diabetes patients and 50.7% of hypertension patients triggered severe, moderate, or duplicative alerts. Among diabetes patients, 74.3% of duplicative alerts were trivial or inappropriate, compared with 3.9% among hypertension patients. Experts judged that 40.5% of high-risk diabetes patients and 53.6% of hypertension patients had alerts requiring nurse follow-up. Adequate follow-up was significantly lower for the former. The relationship between inappropriate alerts and poorer follow-up reinforces the need for more specific alert systems to focus clinicians' attention on clinically important alerts.

Service scripts: a tool for teaching pharmacy students how to handle common practice situations

OBJECTIVES

This paper describes the use of service scripts to teach pharmacy students how to manage specific practice situations by learning and following scripted behaviors.

DESIGN

Based upon role theory, service scripts require specific behaviors for a broad range of practice problems and communicate consistent messages about the responsibilities of all people involved. Service scripts are developed by (1) identifying scenarios for the script, (2) eliciting the script's structure and content, and (3) documenting the reasoning behind the steps in the script.

ASSESSMENT

Students in a nontraditional doctor of pharmacy program developed scripts for their practice settings. They concluded that scripts were useful for quickly learning new, routine tasks, but expressed concern that scripts could be misused by pharmacists and managers. The process of script development itself was useful in gaining feedback about common practice problems.

CONCLUSION

By mastering managerial, clinical, and communication scripts, students can develop capabilities to provide professional services.

Co-dispensing of contraindicated medications in patients using cisapride in Italy

PURPOSE

To investigate the co-dispensing of contraindicated medications in patients using cisapride in an Italian population.

METHODS

The study included patients who had at least one cisapride prescription dispensed between 1 April 1997 and 30 September 2000. The proportion of cisapride users with concomitant medications, the proportion of prescriptions of cisapride with an overlapping dispensing of a contraindicated medication and the proportion of person-days of cisapride use concomitant with contraindicated medications, were calculated.

RESULTS

In the 4-year study period, 249,740 total cisapride prescriptions, which corresponded to 382,835 packages, were dispensed to 91,204 users (52,442 female, 57.5%). Concomitant use of contraindicated drugs was identified in 4403 cisapride users (4.83%). Throughout the study period, there was an increase in the proportion of cisapride users with contraindicated co-prescriptions: 4.29% in 1997, 4.99% in 1998, 5.15% in 1999, but a decline to 3.34% in 2000. In each year, this figure was higher in males, with the highest proportion reported in 1999 (5.50%). A total of 7215 cisapride prescriptions (2.85%) were concomitant with contraindicated drugs, ranging from 2.27% in September 1998 to 3.55% in January 1999. Cisapride prescriptions were most frequently associated with macrolide antibiotics (1.14%) and class III antiarrhythmics (1.03%).

CONCLUSIONS

In the period 1997-2000, a substantial proportion of cisapride prescriptions were concomitant with contraindicated medications. In Italy in 1998, the National Health Authority issued a bulletin warning about the risk of serious arrhythmias after concomitant use of contraindicated drugs. Despite this warning, there was no reduction in contraindicated drug uses.

Incidence and possible causes of prescribing potentially hazardous/contraindicated drug combinations in general practice

BACKGROUND

Preventing the use of medications where there is the potential for serious drug-drug interactions or drug-disease interactions (contraindications) is essential to ensure patient safety. Previous studies have looked at the incidence of prescribing contraindicated drug combinations, but little is known about the underlying reasons for the co-prescribing events. The objectives of this study were to estimate the incidence of prescribing contraindicated drug combinations in general practice and to explore the clinical context, possible causes and potential systems failures leading to their occurrence.

METHODS

A list of contraindicated drug combinations was compiled according to established references. A search of computerised patient medication records was performed, followed by detailed chart review and assessment. The patient records from four general practices in an area of England were searched for a period of 1 year (1 June 1999-31 May 2000) to identify contraindicated drug combinations. All patients registered with the four participating practices during the study period were included (estimated n = 37 940). Medical records of the cases identified by the computer search were reviewed in detail and relevant information was extracted. Each case was then independently assessed by a pharmacist and a physician who judged whether the co-prescribing was justified and whether it was associated with an adverse drug event. Proximal causes and potential systems failures were suggested for each co-prescribing event.

MAIN OUTCOME MEASURES AND RESULTS

Fourteen patients with potential drug-drug interactions and 50 patients with potential drug-disease interactions were identified. Overall, these represent an incidence of 1.9 per 1000 patient-years (95% CI 1.5, 2.3) or 4.3 per 1000 patients being concurrently prescribed > or =2 drugs per year (95% CI 3.2, 5.4). 62 cases involving 63 co-prescribing events were reviewed. Two-thirds of these events involved medications that were initiated by hospital doctors. Awareness of the potential drug-drug or drug-disease interactions was documented in one-third of the events at the time of initial co-prescribing. Within the study period, the co-prescribing was judged to be not justified in 44 events (70%). Potential drug-drug interactions possibly resulted in two adverse drug events. The majority of contraindicated co-prescribing related to drug-disease interactions involved the use of propranolol or timolol eye drops for patients receiving bronchodilators and the use of amiodarone for patients receiving levothyroxine sodium.

CONCLUSION

The prescribing of contraindicated drug combinations was relatively rare in this study. Multiple possible causes and systems failures were identified and could be used to develop strategies for the prevention of prescribing errors involving contraindicated drug combinations in primary care.

Impact of mailed warning to prescribers on the co-prescription of tramadol and antidepressants

PURPOSE

An evaluation was made of the effectiveness in changing prescribing behavior of 'Dear Health Professional (DHP)' letters mailed by the manufacturer to physicians and other health professionals advising them of safety information on co-prescribing of tramadol and antidepressants.

METHODS

A retrospective cohort analysis of prescription claims of all plan members from 12 UnitedHealth Group-affiliated health plans who received a first prescription for tramadol between 1 April 1995 and 31 December 1996. The prevalence of co-prescribing of antidepressants and tramadol relative to the date of the 'DHP' communication was determined.

RESULTS

9218 plan members received an initial prescription for tramadol within the observation period. Prior to the date of the 'DHP' communication 1061/4774 (22.2%) members received a prescription for an antidepressant within 30 days of their first prescription for tramadol. Following the date of the communication 844/4444 (19.0%) of members received an antidepressant within 30 days of their first prescription for tramadol. An overall decreasing linear trend in antidepressant co-prescribing was evident over the observation period, but there was no statistically significant acceleration in the decrease following this communication.

CONCLUSIONS

The mailed 'DHP' advisory letter did not affect the rate of co-prescribing of tramadol with antidepressants.

Deadly drug interactions in emergency medicine

Many life-threatening drug interactions are predictable, avoidable events. Emergency medicine physicians have a responsibility to recognize and prevent drug interactions. Keeping current on the many pharmaceutical therapies,their pharmacology, and potential drug interactions currently represents one of the biggest challenges for emergency medicine practitioners. Using current drug interaction resources and knowing the limited number of medications that are responsible for the most serious drug interactions can ease this seemingly overwhelming burden greatly. Clinicians need to be particularly vigilant when prescribing drugs for patients who are taking medications with potential for drug interactions leading to serious consequences.

Impact of safety warnings on drug utilization: marketplace life span of cisapride and troglitazone

STUDY OBJECTIVE

To evaluate the impact of safety alerts on the volume of cisapride and troglitazone usage.

DESIGN

Retrospective database analysis.

SETTING

University research center.

MATERIAL

Idaho Medicaid claims data from January 1994--July 2000.

MEASUREMENTS AND MAIN RESULTS

Monthly counts of total and new prescriptions filled for cisapride and troglitazone were analyzed graphically over time as a function of all prescriptions. New prescriptions were defined as those filled by patients who had not received the drug within the previous year. A binomial comparison of the 5 months before and after each safety alert was conducted by Poisson distribution. Overall and new cisapride usage increased after the first alert, which occurred in February 1995 (p<0.05). After the second alert, in September 1995, growth in new prescriptions ended but total prescriptions continued to grow (p<0.05). After the third alert, in June 1998, growth in total use ended and the number of new prescriptions declined (p<0.05). The final two alerts (June 1999 and January 2000) were met with significant declines (p<0.05 for both). Troglitazone was the subject of two alerts in October and December 1997. After these, overall usage increased (p<0.05), whereas the number o new prescriptions decreased (p<0.05). The third alert, in July 1998, caused no change as total prescription use continued to grow (p<0.05), whereas the number of new prescriptions decreased (p<0.05). A fourth alert, in June 1999, resulted in a decrease of overall usage and new prescriptions (p<0.05 for both).

CONCLUSION

Numerous safety alerts were required for each drug before drug usage declined. The decline in overall use was slower than the decline in new prescriptions, possibly indicating a need for increased assessment of refilled prescriptions after the release of new safety data.

Communication of medical product risk: how effective is effective enough?

Ever-increasing attention is being paid worldwide to the safety of medical products, and the risks associated with their use. The integral role of risk communication in overall risk management is demonstrated by several recent market withdrawals of drugs, in which a perceived incapability of healthcare systems to manage well-characterised, avoidable risks was a significant factor. With advances in clinical pharmacology, pharmacogenomics and pharmacoepidemiology expanding our knowledge of medical products, effective delivery of the latest safety-related information to health professionals and consumers becomes even more imperative. In this regard, it is important to evaluate whether current modes of risk communication lead to desired changes in relevant behaviours such as prescribing or drug monitoring, particularly in context with which achieved level of effectiveness is deemed acceptable. This is crucial, as there have been product-specific risk communication efforts that achieved a fair degree of success, yet were not seen as effective enough to prevent market withdrawal of the medical product in question. In the service of improving public health through enhanced risk communication, it is essential to critically assess current methods, both as to results achieved (or not), and whether each method is applicable to the various types of risks associated with medical product use. Furthermore, just as combining methods may well improve overall risk communication, there are societal and psychological factors that must be considered in attempting to maximise effectiveness. However, in assessing risk communication effectiveness, the particular benefit- risk relationship of any individual medical product must also be part of the evaluative process.

Impact of regulatory labeling for troglitazone and rosiglitazone on hepatic enzyme monitoring compliance: findings from the state of Ohio medicaid program

PURPOSE

Troglitazone, the first drug of the thiazolidinediones class for type II diabetes, was first marketed in March 1997 and was removed from the U.S. market 36 months later after 90 cases of liver failure were reported despite multiple warnings containing liver enzyme monitoring recommendations. Rosiglitazone has been available since June 1999 and is still on the market. The purpose of this study was to evaluate the impact of labeled hepatic enzyme monitoring for troglitazone and rosiglitazone.

METHODS

Drug cohorts were assembled, using population-based fee-for-service Medicaid claims, for patients between 18 and 65 years of age who had received at least one troglitazone (n = 7226) or rosiglitazone (n = 1480) prescription between 1 April, 1997, and 21 March, 2000. The outcome of interest was the percentage of patients, based on their first treatment episode, who had baseline and post-baseline liver enzyme testing.

RESULTS

Overall baseline testing was under 9% before regulatory actions, increased to 14% after the first two 'Dear Doctor' letters issued by the FDA in October and December 1997, and peaked to about 26% afterwards. Coincident with the marketing of rosiglitazone and the fourth 'Dear Doctor' letter issued in June 1999, baseline testing dropped to 18%. Baseline testing increased 2.5-fold (race-sex-age adjusted) after regulatory action. Achieving 50% post-baseline testing took approximately 6 months for both drugs.

CONCLUSION

Regulatory actions had only modest effects on the incidence of liver monitoring. More effective and timely communication strategies, health provider prescribing interventions and modification of health provider behaviors to enhance compliance with recommended risk management measures need to be identified, evaluated and implemented.

Physician and practice characteristics associated with the early utilization of new prescription drugs

BACKGROUND

Prescription of new drugs contributes to substantial increases in annual drug expenditures. A small proportion of physicians appear to be early users of new prescription drugs and little is known about their characteristics.

OBJECTIVE

To estimate the initial utilization rate of new prescription drugs among physicians, and the physician and practice characteristics associated with early use.

DESIGN

Cumulative prospective assessment over a 5 year period (1989-1994) of new drug utilization rates in a randomly selected cohort of Quebec physicians.

PARTICIPANTS

1661 physicians and 669,867 elderly patients.

OUTCOME

Prescribing rate of 20 new drugs, in 6 therapeutic categories, to elderly patients in the first 6 months after inclusion in the Quebec formulary.

RESULTS

The 20 new drugs were prescribed by 1.3-22.3% of physicians, and there was an 8 to 17-fold difference in new drug utilization rates among prescribers. Characteristics associated with higher rates of utilization differed for general practitioners and specialists. Male general practitioners, and physicians graduating from the most recently established medical school in the province, had higher rates of new drug utilization, whereas recent graduation was only associated with higher utilization rates among specialists. Practice volume was associated with higher rates of utilization among GPs. For both GPs and specialists, having a high proportion of elderly in one's practice and a rural or remote practice location was associated with lower utilization rates.

CONCLUSIONS

Physician sex, specialty, medical school, years since graduation, practice location, volume, and relative proportion of elderly in the physician's practice influence the utilization of new drugs.

Impact of cisapride label changes on codispensing of contraindicated medications

OBJECTIVE

To quantify the impact of the first three label changes and 'Dear Doctor' letters as sole interventions, sent to prescribers and pharmacists, on the prescribing and dispensing of cisapride and contraindicated drugs.

METHODS

Using a managed care claims database, a total of 38,757 patients with cisapride prescriptions (July 1993-December 1998) were selected. An interrupted time series analysis and an exponentially weighted moving average analysis (EWMA) were conducted to determine whether there were changes in the proportion of contraindicated codispensing following each intervention.

RESULTS

3.6% of cisapride dispensing overlapped with contraindicated drug dispensing. Beginning in 1994, the overlapped proportions declined slowly from 4.5% ending at 3.2% in 1998. The interrupted time series analysis showed that there was a statistically significant abrupt permanent decrease in the proportion of contraindicated dispensing following the June 1998 label change (coefficient -1.0094, p = 0.045), meaning that the proportion of contraindicated dispensing dropped nearly one percentage point after the third intervention. The 1995 label changes did not have statistically significant effects. The EWMA analysis showed that the proportion of contraindicated dispensing was lower than 3 standard deviations below average during the period after the June 1998 intervention, with no significant effects following the two earlier interventions.

CONCLUSIONS

The June 1998 cisapride label change and accompanying 'Dear Doctor' letter had a downward impact on the proportion of dispensing of contraindicated drugs with cisapride. The other two label changes did not have independent significant impacts.

Labelling and 'Dear Doctor' letters: are they noncommittal?

Over the past few years, a number of drugs have been withdrawn for safety reasons, either by drug approval authorities, or by the manufacturer. A recent example is the withdrawal of cerivastatin in connection with rhabdomyolysis. Several other drugs have also been taken off the market as a security measure, not because the nature of the risk involved was unknown but because the risk had proved apparently uncontainable. It seems that the inclusion of a warning or contraindication in the Summary of Product Characteristics (SPC) or sending a 'Dear Doctor' letter is insufficient to ensure compliant prescription behaviour. There appears to be a discrepancy between the careful use of evidence underpinning the SPC content and formal warnings and changes to the SPC and the effect they have on the prescription and dispensing of the drugs involved. This results in undue loss or damage for both the manufacturer and the patient. There are no easy solutions to tackle this problem; the ineffectiveness of labelling and 'Dear Doctor' letters has ramifications for the whole regulatory/ industrial/educational complex. We discuss briefly four possible strategies for improving the current situation, with the emphasis on the place the prescriber has in this process. The first strategy is education-based. Clinicians need to know about the comparative merits of the effectiveness and risk of drugs, as well as how they work pharmacologically, toxicologically, and what interactions they have with each other. The second strategy involves improving the information available for clinicians. Frequently, physicians do not consult the SPC for verification, leaving aside whether they have taken notice of the contents of the official SPC in the first place. It is recommended that the accessibility of SPCs is enhanced for doctors and pharmacists, drawing attention specifically to any changes. There needs to be a single body of information that covers every drug. The third strategy involves communication. There is much to be done in this area both in terms of follow-up and understanding of health professional's behaviour and how to empower best practise. The final strategy involves professional freedom. It goes without saying that doctors who issue off-label prescriptions may need to justify their actions. Deviating from the SPC should always be a considered decision and health professionals need to be aware of the additional responsibilities associated with such a decision. The dispensing pharmacist can play an important role in the implementation of warnings and contraindications.

Improving communication of drug risks to prevent patient injury: proceedings of a workshop

PURPOSE

The Centers for Education & Research on Therapeutics (CERTs) is conducting a series of workshops on managing the risks of therapeutics, with the ultimate goal to develop an agenda for research and education about risk and its management. This paper presents the results of the first workshop in the series, a 2-day meeting focused on communication of drug risks to healthcare professionals and patients.

METHODS

The 50 workshop participants represented the medical-products industry, academia, consumer groups, regulatory bodies and the media. Together, they sought to identify and understand barriers to successful risk communication, to identify tools or methods that could improve risk communication, and to develop research and education agendas that would lead to better risk communication in the future.

RESULTS

Limitations of current methods of risk communication were identified, and research and education agendas were proposed to clarify and resolve these issues.

CONCLUSION

Common themes for potential solutions include enhanced education of healthcare providers, increased motivation of patients and families, use of creative communication technologies, and better organization of and access to medical records and information.

Spontaneous adverse event reports of serious ventricular arrhythmias, QT prolongation, syncope, and sudden death in patients treated with cisapride

CONTEXT

Adverse cardiac events, typically long QT syndrome, have been reported in patients treated with the gastrointestinal prokinetic agent cisapride.

OBJECTIVE

To analyze cases of cisapride-associated long QT syndrome and ascertain the degree of confidence in the diagnosis of long QT syndrome and the presence of risk factors.

DESIGN

Review of all cases reported to the manufacturer, health authorities, or in the medical literature as of October 1999.

METHODS

Before review, specific definitions and a classification scheme were agreed upon. Each case was classified by confidence in the long QT syndrome diagnosis and the presence of recognized risk factors (cofactors) or other medical conditions that were listed as contraindications in the June 1998 United States labeling (labeled conditions).

RESULTS

Of 574 cases reviewed, 391 cases of long QT syndrome or isolated QT prolongation were confirmed. Most of these were classified as long QT syndrome with high (145, 37%) or medium (92, 23.5%) confidence in the diagnosis. Recognized cofactors were present in 262 (67%) cases. The proportion of cases with recognized cofactors rose with confidence in the diagnosis (P < 0.001) from 42.2% in the low-confidence group to 68.5% and 82.1% in the medium- and high-confidence groups, respectively. Conversely, the proportion of cases with other labeled conditions decreased with confidence in the diagnosis, from 33.3% for low confidence to 13% and 8.3% for medium and high confidence, respectively. Analysis of cases and prescribing data showed reporting rates decreased in studied months in 1999 compared with the average study period.

CONCLUSION

In most cases with high or medium confidence in the diagnosis of cisapride-associated long QT syndrome, recognized cofactors for long QT syndrome were present. The risk of cisapride-related long QT syndrome may be minimized by avoiding cofactors.

Decision support and safety of clinical environments

Safety in the clinical environment is based on structures that reduce the probability of harm, on evidence that enhances the likelihood of actions that increase favourable outcomes, and on explicit directions that lead to decisions to implement the actions dictated by this evidence. A clinical decision error rate of only 1% threatens patient safety at a distressing frequency. Explicit computerised decision support tools standardise clinical decision making and lead different clinicians to the same set of diagnostic or therapeutic instructions. They have favourable impacts on patient outcome. Simple computerised algorithms that generate reminders, alerts, or other information, and protocols that incorporate more complex rules reduce the clinical decision error rate. Decision support tools are not new; it is the new attributes of explicit computerised decision support tools that deserve identification. When explicit computerised protocols are driven by patient data, the protocol output (instructions) is patient specific, thus preserving individualized treatment while standardising clinical decisions. The expected decrease in variation and increase in compliance with evidence-based recommendations should decrease the error rate and enhance patient safety.