Lack of awareness of community-acquired adverse drug reactions upon hospital admission : dimensions and consequences of a dilemma

Therapeutic Drug Monitoring and Pharmacogenetic Tests as Tools in Pharmacovigilance

Therapeutic drug monitoring (TDM) and pharmacogenetic tests play a major role in minimising adverse drug reactions and enhancing optimal therapeutic response. The response to medication varies greatly between individuals, according to genetic constitution, age, sex, co-morbidities, environmental factors including diet and lifestyle (e.g. smoking and alcohol intake), and drug-related factors such as pharmacokinetic or pharmacodynamic drug-drug interactions. Most adverse drug reactions are type A reactions, i.e. plasma-level dependent, and represent one of the major causes of hospitalisation, in some cases leading to death. However, they may be avoidable to some extent if pharmacokinetic and pharmacogenetic factors are taken into consideration. This article provides a review of the literature and describes how to apply and interpret TDM and certain pharmacogenetic tests and is illustrated by case reports. An algorithm on the use of TDM and pharmacogenetic tests to help characterise adverse drug reactions is also presented. Although, in the scientific community, differences in drug response are increasingly recognised, there is an urgent need to translate this knowledge into clinical recommendations. Databases on drug-drug interactions and the impact of pharmacogenetic polymorphisms and adverse drug reaction information systems will be helpful to guide clinicians in individualised treatment choices.

How important is the role of the physician in the correct use of a drug? An observational cohort study in general practice

The correct use of a drug is determined by several important factors. The most significant of these is a correct diagnosis for the choice of the appropriate therapeutic approach, followed by the physician's awareness of each drug's product characteristics--such as indications, contraindications and warnings--and by a careful evaluation of the patient in order to consider possible risk factors, concomitant pathologies and treatments. An adequate knowledge of pharmacological therapy and of the patient's history and disease states could in fact prevent most of the adverse drug reactions attributable to an inappropriate prescription. It is clear that the physician's role in the correct use of a drug is extremely important. Observational studies and surveys evaluating doctors' prescribing habits could be a very useful instrument in identifying medication prescribing errors and the consequent occurrence of adverse events. An open-label, multicentre, observational cohort study, recently performed in Ireland and involving more than 9000 patients, investigated the use of non-steroidal anti-inflammatory drugs (NSAIDs) in general practice, and in particular the use of diclofenac, nimesulide and ibuprofen. These three drugs were shown to be the NSAIDs most frequently prescribed (80% of total prescriptions) by general practitioners in Ireland. The study was designed and powered to detect differences in the general safety profile of the three NSAIDs and to test prescribing physicians' compliance with each drug's Summary of Product Characteristics (SmPC). The study was performed as closely as possible to the normal prescribing habits of the participating physicians. The three drugs were shown to be well tolerated. In the nimesulide group, the percentage of patients who experienced treatment-related adverse events was lower than that of the diclofenac group and similar to that observed with the use of ibuprofen. A more favourable gastrointestinal safety profile was evident for nimesulide in comparison to diclofenac. The data showed that the study physicians prescribed the drugs with a good degree of compliance (84% of prescriptions) with the information reported in each of the SmPCs. This supported the fact that the adverse events were markedly limited.

Epidemiology of hypersensitivity drug reactions

PURPOSE OF REVIEW

Hypersensitivity drug reactions are but one of the many different types of adverse drug reactions. They may be potentially life-threatening, prolong hospitalization, affect drug prescribing patterns of physicians and result in socioeconomic costs. This review summarizes current knowledge on the incidence, prevalence, mortality and risk factors for these reactions in different populations.

RECENT FINDINGS

Hypersensitivity reactions represent about one third of all adverse drug reactions. Adverse drug reactions affect 10-20% of hospitalized patients and more than 7% of the general population. Severe reactions including anaphylaxis, drug hypersensitivity syndromes, Stevens Johnson syndrome and toxic epidermal necrolysis are also associated with significant morbidity and mortality. Although several risk factors have been identified, their clinical importance has not been fully understood. Future progress in immunogenetics and pharmacogenetics may help identify populations at risk for specific types of reactions.

SUMMARY

Well designed epidemiological studies on hypersensitivity drug reactions are lacking as most studies have been on adverse drug reactions. Such studies will be helpful in identifying patients at risk of developing such reactions, in particular severe reactions, and implementing early preventive measures.

Pharmacogenomics steps toward personalized medicine

The goal of personalized medicine is to maximize the likelihood of therapeutic efficacy and to minimize the risk of drug toxicity for an individual patient. One of the major contributors to this concept is pharmacogenomics. Marked interindividual genetic variation contributes significantly to both susceptibility to diseases, and response to drugs. Even though pharmacogenomics is not a new science, the translation of pharmacogenomics into clinical practice (i.e., personalized medicine) has not taken place at the same pace as science is delivering new results. It is felt that a large number of recent pharmacogenomic findings allow bold steps to be taken toward personalized medicine. This review collates a variety of examples that have great potential for immediate and effective introduction into clinical practice. In addition, other exploratory examples with a particular focus on drug safety and targeted cancer therapy are summarized.

[Frequency, relevance, causes of and strategies for prevention of medication errors]

Drug therapy has led to major advances in medicine. The beneficial effects of drug therapy are coupled with the inevitable risk of adverse drug reactions especially in elderly patients. Many adverse drug reactions are preventable. The electronic health card that will be introduced in Germany starting in 2006 is designed to support electronic decision support to prevent medication errors. Studies have demonstrated that CPOES can reduce medication errors by 80%. The necessary steps to improve medication safety in Germany are outlined and discussed.

Pharmacogenomics Education: International Society of Pharmacogenomics Recommendations for Medical, Pharmaceutical, and Health Schools Deans of Education

Pharmacogenomics would be instrumental for the realization of personalized medicine in coming decades. Efforts are evident to clarify the potential bioethical, societal, and legal implications of key pharmacogenomics-based technologies projected to be soon introduced into the core practice of medicine. In sharp contrast, a lack of sufficient attention to educational aspects of pharmacogenomics, both for professionals and for society at large, is evident. In order to contribute to this discussion, a 'Pharmacogenomics Education Forum' was held on October 2, 2004 during the 3rd Annual Meeting of the International Society of Pharmacogenomics (ISP) at Santorini, Greece. The participants, members of the ISP Pharmacogenomics Education Forum, after deliberate discussions, proposed a document of 'Background Statement' and 'Recommendations and Call for Action' addressed to Deans of Education at Medical, Pharmaceutical, and Health Schools globally. This document has been considered by the education committee of the International Society of Pharmacogenomics and the result is presented here. We hope that this call would be listened to, and soon followed by beneficial action, ultimately leading to enhanced implementation of personalized medicine into core medical education and practice.

Identification of adverse drug reactions in geriatric inpatients using a computerised drug database

INTRODUCTION AND OBJECTIVE

Geriatric patients with multiple comorbidities are at high risk of experiencing an adverse drug reaction (ADR) during hospitalisation. The aim of the study was to compare the rate of ADRs as predicted by a computerised pharmacological database to the actual rate determined by direct observation in a sample of geriatric patients.

STUDY DESIGN

During a 4-month period, geriatric patients were monitored using prospective observation. Patients were intensively screened for ADRs by a pharmacoepidemiological team (PET), consisting of two pharmacists and a physician. Actual ADRs detected by the PET were compared with those predicted by a computerised drug database. Furthermore, the set of actual ADRs, which resulted from drug-drug interactions (DDIs), were contrasted with potential DDIs signalled by the database. The main outcome measures were the incidence of actual ADRs. For the detection rate of the database we focused on frequent ADRs (>1% according to product information and database) and all DDIs indicated automatically by the database.

RESULTS

163 patients (121 female), mean age 79.8 +/- 7.1 years (range 60-98), were included in the study which was conducted on a geriatric rehabilitation hospital ward. The mean duration of hospitalisation was 24.3 +/- 8.4 days. Elderly patients received an average of 14.0 drugs (range 2-35) during their hospital stay. Of all patients, 60.7% experienced at least one ADR. The PET detected a total of 153 ADRs, with a mean of 0.9 ADRs per patient (range 0-5). The computerised drug database predicted an average of 309 potential ADRs for each patient; however, only 21 ADRs per patient were of high frequency. In 48% of ADR-positive patients (defined by PET) at least one of these frequent ADRs occurred.DDIs were detected by the PET in 14.7% of patients. Our database indicated a mean of 12 potential DDIs per patient. In 14 out of 24 DDI-positive patients, at least one signal indicated a real DDI. The database sensitivity was consequently 58.3%.

CONCLUSION

In geriatric patients the incidence of ADRs is high. Computerised drug databases are a useful tool for detecting and avoiding ADRs. Our software, however, also produced a large number of signals that did not relate to actual ADRs found by the PET. The sheer number of these 'false' signals shows the need for refinement and optimisation of databases for daily clinical use.