Adverse drug reactions

Age-related differences in susceptibility to cisplatin-induced renal toxicity

Limited experimental models exist to assess drug toxicity in pediatric populations. We recently reported how a multi-age rat model could be used for pre-clinical studies of comparative drug toxicity in pediatric populations. The objective of this study was to expand the utility of this animal model, which previously demonstrated an age-dependent sensitivity to the classic nephrotoxic compound, gentamicin, to another nephrotoxicant, namely cisplatin (Cis). Sprague-Dawley rats (10, 25, 40 and 80 days old) were injected with a single dose of Cis (0, 1, 3 or 6 mg kg(-1) i.p.). Urine samples were collected prior and up to 72 h after treatment in animals that were >or= 25 days old. Several serum, urinary and 'omic' injury biomarkers as well as renal histopathology lesions were evaluated. Statistically significant changes were noted with different injury biomarkers in different age groups. The order of age-related Cis-induced nephrotoxicity was different than our previous study with gentamicin: 80 > 40 > 10 > 25 day-old vs 10 >or= 80 > 40 > 25-day-old rats, respectively. The increased levels of kidney injury molecule-1 (Kim-1: urinary protein/tissue mRNA) provided evidence of early Cis-induced nephrotoxicity in the most sensitive age group (80 days old). Levels of Kim-1 tissue mRNA and urinary protein were significantly correlated to each other and to the severity of renal histopathology lesions. These data indicate that the multi-age rat model can be used to demonstrate different age-related sensitivities to renal injury using mechanistically distinct nephrotoxicants, which is reflected in measurements of a variety of metabolite, gene transcript and protein biomarkers.

Adverse drug reaction reporting in Australian hospitals

Objective

To determine the status of adverse drug reaction (ADR) reporting in Australian hospitals. Method Postal questionnaire to all 299 directors of pharmacy in Australian hospitals.

Key findings

The response rate was 49.5%. Hospitals of different size were well represented: <100 beds (23%), 100–199 beds (35%) and 200–499 beds (30%). ADR policies were reported by 67% of pharmacy departments. In most hospitals, doctors or pharmacists were responsible for ADR submissions to the Australian ADR Advisory Committee (ADRAC). Follow-up action included reports to Drug and Therapeutics Committees (57%) and drug bulletins (37%). Advice on ADRs was forwarded to the patient, the general practitioner (GP) and the community pharmacist by 96%, 89% and 11% of hospitals. Methods of informing patients were verbal (91%), card (17%) or letter (13%). Methods used to notify GPs included discharge summary (70%), letter (26%) or via the patient (15%). Data from ADRAC indicated a median 2.5 (range 0–362) reports from participating hospitals in 2000. The median ADR reporting rate was 0.02% (range 0–1.09) of patient admissions. There was no association between ADR reporting rates and the existence of an ADR policy or a centralised ADR reporting system. There was an association between hospital ADR reporting rates and provision of feedback or a reward for ADR reporting (P<0.001).

Conclusions

Procedures or policies for ADR reporting are available in most Australian hospitals but this has no direct effect on ADR reporting rates. These findings suggest a gap between policy and implementation of ADR reporting. Strategies to improve ADR reporting could include improved feedback and electronic submissions to ADRAC from a centralised service.

Data mining on electronic health record databases for signal detection in pharmacovigilance: which events to monitor?

PURPOSE

Data mining on electronic health records (EHRs) has emerged as a promising complementary method for post-marketing drug safety surveillance. The EU-ADR project, funded by the European Commission, is developing techniques that allow mining of EHRs for adverse drug events across different countries in Europe. Since mining on all possible events was considered to unduly increase the number of spurious signals, we wanted to create a ranked list of high-priority events.

METHODS

Scientific literature, medical textbooks, and websites of regulatory agencies were reviewed to create a preliminary list of events that are deemed important in pharmacovigilance. Two teams of pharmacovigilance experts independently rated each event on five criteria: 'trigger for drug withdrawal', 'trigger for black box warning', 'leading to emergency department visit or hospital admission', 'probability of event to be drug-related', and 'likelihood of death'. In case of disagreement, a consensus score was obtained. Ordinal scales between 0 and 3 were used for rating the criteria, and an overall score was computed to rank the events.

RESULTS

An initial list comprising 23 adverse events was identified. After rating all the events and calculation of overall scores, a ranked list was established. The top-ranking events were: cutaneous bullous eruptions, acute renal failure, anaphylactic shock, acute myocardial infarction, and rhabdomyolysis.

CONCLUSIONS

A ranked list of 23 adverse drug events judged as important in pharmacovigilance was created to permit focused data mining. The list will need to be updated periodically as knowledge on drug safety evolves and new issues in drug safety arise.

Pharmacogenetics of idiosyncratic adverse drug reactions

Idiosyncratic adverse drug reactions are unpredictable and thought to have an underlying genetic etiology. With the completion of the human genome and HapMap projects, together with the rapid advances in genotyping technologies, we have unprecedented capabilities in identifying genetic predisposing factors for these relatively rare, but serious, reactions. The main roadblock to this is the lack of sufficient numbers of well-characterized samples from patients with such reactions. This is now beginning to be solved through the formation of international consortia, including developing novel ways of identifying and recruiting patients affected by these reactions, both prospectively and retrospectively. This has been led by the research on abacavir hypersensitivity - its association with HLA-B*5701 forms the gold standard of how we need to identify associations and implement them in clinical practice. Strong genetic predisposing factors have also been identified for hypersensitivity reactions such as are associated with carbamazepine, allopurinol, flucloxacillin, and statin-induced myopathy. However, for most other idiosyncratic adverse drug reactions, the genetic effect sizes have been low to moderate, although this may partly be due to the fact that only small numbers have been investigated and limited genotyping strategies have been utilized. It may also indicate that genetic predisposition will be dependent on multiple genes, with complex interactions with environmental factors. Irrespective of the strength of the genetic associations identified with individual idiosyncratic adverse drug reactions, it is important to undertake functional investigations to provide insights into the mechanism(s) of how the drug interacts with the gene variant to lead to a phenotype, which can take a multitude of clinical forms with variable severity. Such investigations will be essential in preventing the burden caused by idiosyncratic reactions, both in healthcare and in industry.

Role of reactive metabolites in drug-induced hepatotoxicity

Drugs are generally converted to biologically inactive forms and eliminated from the body, principally by hepatic metabolism. However, certain drugs undergo biotransformation to metabolites that can interfere with cellular functions through their intrinsic chemical reactivity towards glutathione, leading to thiol depletion, and functionally critical macromolecules, resulting in reversible modification, irreversible adduct formation, and irreversible loss of activity. There is now a great deal of evidence which shows that reactive metabolites are formed from drugs known to cause hepatotoxicity, such as acetaminophen, tamoxifen, isoniazid, and amodiaquine. The main theme of this article is to review the evidence for chemically reactive metabolites being initiating factors for the multiple downstream biological events culminating in toxicity. The major objectives are to understand those idiosyncratic hepatotoxicities thought to be caused by chemically reactive metabolites and to define the role of toxic metabolites.

Partial progress: governing the pharmaceutical industry and the NHS, 1948-2008

Coinciding with sixty years of the U.K. National Health Service (NHS), this article reviews the neglected area of the governance of the pharmaceutical industry and the NHS. It traces the relationships between the pharmaceutical industry, the state, and the NHS from the creation of the health service to the present, as they have grappled with the overlapping challenges of pharmaceutical safety, efficacy, cost-effectiveness, pricing, promotion, and advertising. The article draws on the concepts of "corporate bias" and "regulatory capture" from political theory, and "counter-vailing powers" and "clinical autonomy" in medical sociology, while also introducing the new concepts of "assimilated allies" and "pharmaceuticalization" in order to synthesize a theoretical framework capable of longitudinal empirical analysis of pharmaceutical governance. The analysis identifies areas in which the governance of pharmaceuticals and the NHS has contributed to progress in health care since 1948. However, it is argued that that progress has been slow, restricted, and vulnerable to misdirection due to the enormous and unrivaled influence afforded to the pharmaceutical industry in policy developments. Countervailing influences against such corporate bias have often been limited and subject to destabilization by the industry's assimilated allies either within the state or in the embrace of pharmaceuticalization and consumerism.

Drug interactions and adverse events associated with antimycotic drugs used for invasive aspergillosis in hematopoietic SCT

The aim of this study was to assess the frequency of potential drug-drug interactions (pDDIs) and adverse drug events (ADEs) associated with antimycotics in hospitalized patients with hematopoietic SCT (HSCT). Of the 120 HSCT recipients evaluated, 36 received antimycotics. A total of 124 ADEs were recorded in 32 of the 36 patients treated, with 54 ADEs being possibly and 9 probably related to antimycotics. Of the treatments with amphotericin B, 93% were associated with one or more possible and 36% with probable ADEs. The corresponding figures for lipid-based amphotericin B were 100% and 7%, for voriconazole 68% and 11% and for caspofungin 70% and 0%. A total of 57 potentially severe DDIs associated with antimycotics were detected in 31 of the 36 patients. Of these, 14 DDIs were a possible cause of an ADE and 5 (4 times a combination of voriconazole with CYA and once a combination of CYA with conventional amphotericin B) were probably related. Although the prevalence of pDDIs and ADEs is high in HSCT patients, ADEs related with a high probability to treatment with antimycotics are rare. Regarding the high prevalence of pDDIs, our findings underscore the importance of close monitoring of laboratory and clinical parameters, as well as dose adjustment for critical drugs, in patients with HSCT.

Pharmacovigilance and new essential drugs in Africa: Zambia draws lessons from its own experiences and beyond

Jolted into action by the thalidomide tragedy, developed Western countries began to establish national systems for identifying and responding to adverse drug reactions and events (or pharmacovigilance systems) about 40 years ago. These systems focus on side effects, adverse reactions, and drug interactions. In developing countries, especially in Africa, the scope for pharmacovigilance needs to be broader (despite the additional challenges this brings) because of growing problems with substandard and counterfeit drugs and the need to have an early warning signal system for the development of antimicrobial resistance to the 'new essential drugs' that are barely beyond the clinical trial stage in Africa, e.g. artemisinin-combination therapy (ACT) for malaria and antiretrovirals (ARV) for HIV/AIDS. Zambia learned important lessons from its own initial experiences in attempting to use ACT as a pathfinder for pharmacovigilance, as well as its experience with other drug information systems. In preparing its own renewed plans, it also drew lessons from international experience, including the weaknesses of the Food and Drug Administration's approach to pharmacovigilance in the USA, the UK's 'yellow card scheme', Brazil's fledgling pharmacovigilance systems for AIDS treatment, and the guidance provided by the World Health Organization and the Uppsala Monitoring Centre. These lessons are relevant for other African countries and even for developed countries seeking to improve pharmacovigilance systems.

Current trends in screening across ethnicities for hypersensitivity to abacavir

Abacavir is a potent nucleoside analog reverse transcriptase inhibitor approved for the treatment of HIV infection. Approximately 5-8% of Caucasian patients receiving abacavir develop a hypersensitivity reaction, characterized by rash, fever and, occasionally, multisystemic involvement. Rechallenge with the drug can be fatal. The discovery of the mechanisms involved in this hypersensitivity reaction and the identification of tools for its prediction are the subject of this review. The most relevant finding is the recognition of a strong association between one specific haplotype at the HLA complex type I, HLA-B*5701, and the abacavir hypersensitivity reaction. The heterogeneity in the prevalence of HLA-B*5701 across distinct ethnicities accounts for differences in the risk of abacavir hypersensitivity reactions in distinct populations.

Knowledge, attitudes, and perceptions of pharmacists to adverse drug reaction reporting in Iran

OBJECTIVE

Adverse Drug Reactions (ADRs) are a major cause of patient morbidity and mortality. Spontaneous reporting of ADRs remains the cornerstone of pharmacovigilance and is important in maintaining patient safety. In order to determine whether our pharmacovigilance system could be improved, and identify reasons for under-reporting, a study to investigate the role of pharmacists in ADR reporting was performed in Shiraz.

SETTING

The pharmacies in Shiraz, capital of Fars province in Iran.

METHODS

A questionnaire was prepared to investigate knowledge and attitude of pharmacists regarding ADR reporting. The questionnaire was given to 200 pharmacists who participated in a pharmacist association meeting.

MAIN OUTCOMES MEASURED

The knowledge of pharmacovigilance practice, reasons for not reporting ADR, and perceptions of the Iranian pharmacists on pharmacovigilance practice were evaluated.

RESULTS

The response rate was 55% (n = 110). 29% of the respondents were not aware of the Iranian Pharmacovigilance Center. More than half of those responding felt that ADR reporting should be voluntary, while 26% felt it was a professional obligation. As for the purposes of ADR reporting scheme, 60% of the pharmacists falsely believed that monitoring ADR spontaneous reports aims at measuring the incidence of ADR. 42% of the pharmacists indicated that they have suspected an ADR without reporting it. Doubt about causality was the major reason for not reporting an ADR. Although our ADR center states that all suspected reactions to any drug on the market must be reported, only 17% of the respondents seemed to be aware of this responsibility.

CONCLUSION

Our pharmacists have little knowledge regarding the operation, purposes, and usefulness of ADR spontaneous reporting system. However, education and training will be important in maintaining and increasing ADR reports from pharmacists.

Adverse drug reactions in patients with cardiovascular disease

Adverse drug reactions (ADRs) occur frequently in modern medical practice, increasing morbidity and mortality and inflating the cost of care. Patients with cardiovascular disease are particularly vulnerable to ADRs due to their advanced age, polypharmacy, and the influence of heart disease on drug metabolism. The ADR potential for a particular cardiovascular drug varies with the individual, the disease being treated, and the extent of exposure to other drugs. Knowledge of this complex interplay between patient, drug, and disease is a critical component of safe and effective cardiovascular disease management. The majority of significant ADRs involving cardiovascular drugs are predictable and therefore preventable. Better patient education, avoidance of polypharmacy, and clear communication between physicians, pharmacists, and patients, particularly during the transition between the inpatient to outpatient settings, can substantially reduce ADR risk.

Improving the reporting of adverse drug reactions: a cluster-randomized trial among pharmacists in Portugal

BACKGROUND

Adverse drug reaction (ADR) reporting systems are the basic component for comprehensive postmarketing surveillance of the risk of drug-induced adverse effects. The aim of this study was to evaluate the effectiveness of educational outreach visits aimed at improving ADR reporting by pharmacists.

METHODS

The study population comprised all pharmacists working in a catchment area covered by Portugal's Northern Regional Health Authority. Using unequal randomization, four spatial-clusters were assigned to the intervention group (n = 342) and eleven to the control group (n = 1091). The intervention took the form of 1-hour long educational outreach visits tailored to training needs detected in a previous study, with a 13- to 16-month follow-up period (March-June 2004 through June 2005). This study is registered as an international standard randomized controlled trial, number ISRCTN45894687.

RESULTS

At baseline, ADR reporting rates (per 1000 pharmacist-years) did not differ significantly between the intervention and control groups (32.28 vs 29.16). The adjusted increase in ADR reporting attributable to the intervention was 275.63 per 1000 pharmacist-years (95% CI 162.15, 389.12; relative risk [RR] = 5.87, 95% CI 1.98, 17.39). The intervention succeeded in multiplying the reporting rate of: serious ADRs, 10-fold (RR = 9.79; 95% CI 2.24, 42.66); unexpected ADRs, 4-fold (RR = 4.41; 95% CI 1.11, 17.53); high-causality ADRs, 9-fold (RR = 8.67; 95% CI 2.12, 35.42); and new drug-related ADRs, 9-fold (RR = 9.33; 95% CI 2.53, 34.40). While the greatest effect was registered during the first 4 months post-intervention, differences remained statistically significant for 8 months.

CONCLUSIONS

Educational outreach visits improve ADR reporting by pharmacists in terms of quantity and relevance.

The Nrf2-Keap1 defence pathway: role in protection against drug-induced toxicity

The metabolic biotransformation of xenobiotics to chemically reactive metabolites can, in some instances, underlie the pathogenesis of certain adverse drug reactions, due to the development of chemical or oxidative stress. In order to guard against such stresses, mammalian cells have evolved multi-faceted, highly-regulated defence systems, one of the most important being that which is regulated by the transcription factor Nrf2. Through regulating the expression of numerous cytoprotective genes, Nrf2 serves as a critical determinant of a cell's capacity to survive, or succumb, to a toxic insult. The aim of this review is to summarise our current understanding of the biochemistry that underlies the Nrf2 defence pathway, and highlight the important role of this transcription factor in the protection against drug-induced toxicity, primarily through the examination of recent investigations that have demonstrated an increased vulnerability to various toxins in animals lacking Nrf2.

Drug-induced yawning: a review of the French pharmacovigilance database

OBJECTIVE

To review the reports with 'yawning' as an adverse drug reaction (ADR) reported into the French Pharmacovigilance Database.

METHODS

All the observations with 'yawning' reported in the French Pharmacovigilance Database until December 2004 were reviewed. We recorded drug(s) involved, characteristics of patients (age, sex and underlying disease) and of ADR (seriousness, delay in occurrence, evolution, imputability).

RESULTS

Twenty-eight reports were recorded between 1985 and December 2004. The sex ratio of the patients included in these reports was 1.5 and the mean age was 46.2 (2-78) years. Thirty-eight drugs were involved, mainly serotoninergic agents (serotonin reuptake inhibitors [12]), dopaminergic agents (levodopa [3], dopamine agonists [3], monoamine oxidase B inhibitor [1]), opioids (morphine [1], methadone [1], buprenorphine [1], dextromethorphan [1]), benzodiazepines (4) and sodium channel inhibitors (lidocaine [2], flecainide [1]). Four ADRs were rated 'serious' (leading to hospitalisation). Patient outcome was usually favourable after drug withdrawal.

CONCLUSION

Despite its necessary methodological drawbacks (mainly under-reporting), this study reveals that several drugs may induce yawning in humans. Our work also indicates that stimulation of central dopamine or serotonin receptors elicits yawning in humans. This study underlines the role of several drugs in yawning and shows that this ADR is not systematically listed in the summary product characteristic even when it can be explained by the pharmacodynamic properties of the drugs.

The utility of a rodent model in detecting pediatric drug-induced nephrotoxicity

A multi-age rat model was used to identify potential age-related differences in renal injury following exposure to gentamicin (GM). In this study, 10-, 25-, 40-, and 80-day-old Sprague-Dawley rats were dosed with GM at 0, 50, or 100 mg kg(-1) body weight per day (mkd) sc for 6 or 14 days. Urine samples were collected up to 72 h after initial dosing. The maximum tolerated dose was lower in 10-day-old rats than for other ages (none survived 11 days of treatment). Eighty-day-old rats given the highest dose showed a diminished rate of growth and an increase in serum creatinine, blood urea nitrogen (BUN), urinary kidney injury molecule-1 (Kim-1), and renal pathology. Ten- and 40-day-old rats given 100 mkd of GM for 6- or 14 days also had increased levels of serum BUN and Cr and renal pathology, whereas only mild renal alterations were found in 25-day-old rats. After 6 days of treatment with 100 mkd GM, significant increases in Havcr-1 (Kim-1) gene expression were detected only in 10- and 80-day-old rats. In urine samples, nuclear magnetic resonance and ultra performance liquid chromatography/mass spectrometry analysis detected changes related to GM efficacy (e.g., hippurate) and increases in metabolites related to antioxidant activity, which was greatest in the 80-day-old rats. The magnitude of the genomic, metabonomic, and serum chemistry changes appeared to correlate with the degree of nephropathy. These findings indicate that an experimental animal model that includes several developmental stages can detect age-related differences in drug-induced organ toxicities and may be a useful predictor of pediatric drug safety in preclinical studies.

Pharmacists' attitudes towards the reporting of suspected adverse drug reactions in Norway

BACKGROUND

In Scandinavian countries, pharmacists have not reported adverse drug reactions (ADRs), either due to legislative restrictions or because of lack of tradition. From 1 January 2005, Norwegian pharmacists have been encouraged by the Norwegian Medicines Agency to take a larger role in the reporting of ADRs.

OBJECTIVE

To explore pharmacists' attitudes towards pharmacovigilance and their experiences with ADR reporting, to evaluate the effect of an educational programme and to compare these findings to the attitudes in a control group.

METHODS

From September 2004, pharmacies in two of Norway's five health regions were invited to attend a 3-month ADR reporting study, and 39 pharmacies were recruited. One pharmacist from each pharmacy participated in a 1 day pre-study educational programme and a 1 day post-study evaluation meeting. Pharmacists involved in the study answered a questionnaire (A) regarding their attitudes to ADR reporting (active group). A control group answered the same questionnaire. One reminder was sent. The active group evaluated the study by answering questionnaire A once more and an evaluation questionnaire (B). Qualitative aspects of ADR reporting were discussed with the active group post-study.

RESULTS

The response rate for questionnaire A was 97% (n = 158) in the active group, 74% (n = 184) in the control group and the response rate for questionnaire A and B post-study was 68% (n = 105) in the active group. Pharmacists in the active group had more positive attitudes to ADR reporting after taking part in the study than the control group (p < 0.001). Lack of time, confidence and knowledge of reporting rules could potentially prevent them from reporting ADRs.

CONCLUSIONS

The pharmacists had positive attitudes towards pharmacovigilance, but very little experience with reporting. The educational programme clarified their role and increased their knowledge about the reporting requirements.

Idiosyncratic adverse reactions to antiepileptic drugs

Idiosyncratic drug reactions may be defined as adverse effects that cannot be explained by the known mechanisms of action of the offending agent, do not occur at any dose in most patients, and develop mostly unpredictably in susceptible individuals only. These reactions are generally thought to account for up to 10% of all adverse drug reactions, but their frequency may be higher depending on the definition adopted. Idiosyncratic reactions are a major source of concern because they encompass most life-threatening effects of antiepileptic drugs (AEDs), as well as many other reactions requiring discontinuation of treatment. Based on the underlying mechanisms, idiosyncratic reactions can be differentiated into (1) immune-mediated hypersensitivity reactions, which may range from benign skin rashes to serious conditions such as drug-related rash with eosinophilia and systemic symptoms; (2) reactions involving unusual nonimmune-mediated individual susceptibility, often related to abnormal production or defective detoxification of reactive cytotoxic metabolites (as in valproate-induced liver toxicity); and (3) off-target pharmacology, whereby a drug interacts directly with a system other than that for which it is intended, an example being some types of AED-induced dyskinesias. Although no AED is free from the potential of inducing idiosyncratic reactions, the magnitude of risk and the most common manifestations vary from one drug to another, a consideration that impacts on treatment choices. Serious consequences of idiosyncratic reactions can be minimized by knowledge of risk factors, avoidance of specific AEDs in subpopulations at risk, cautious dose titration, and careful monitoring of clinical response.

Selection of new chemical entities with decreased potential for adverse drug reactions

Adverse drug reactions, such as hepatotoxicity, blood dyscrasias and hypersensitivity are a major obstacle for the use and the development of new medicines. Many forms of organ-directed toxicity can arise from the bioactivation of drugs to so-called chemically reactive metabolites, which can modify tissue macromolecules. It is well established that the toxicities of model hepatotoxins, such as acetaminophen, furosemide, bromobenzene and methapyrilene can be correlated with the generation of chemically reactive metabolites, which can be detected by measurement of the irreversible binding of radiolabelled material to hepatic protein and/or the detection of stable phase II metabolites such as glutathione conjugates. The basic chemistry of the reaction of such metabolites with model nucleophiles is relatively well understood. A major challenge is to define how certain reactive intermediates may chemically modify critical proteins and how modification of specific amino acids may alter protein function which in turn may affect cell signalling, regulation, defence, function and viability. This in turn will determine whether or not bioactivation will result in a particular form of drug-induced injury. It is now clear that even relatively simple reactive intermediates can react in a discriminative manner with particular cellular proteins and even with specific amino acids within those proteins. Therefore both non-covalent, as well as covalent bonds will be important determinants of the target protein for a particular reactive metabolite. Mammalian cells have evolved numerous defence systems against reactive intermediates. Sensitive redox proteins such as Nrf-2 recognize oxidative stress and electrophilic agents. This is achieved by chemical modification of cysteine groups within keap-1, which normally forms an inactive heterodimer with Nrf-2. Modification of keap-1 releases Nrf-2 that translocates to the nucleus and effects gene transcription of a number of genes involved in the detoxication of chemically reactive metabolites. Diminution of protein function can occur by either covalent modification of nucleophilic amino acids (e.g. cysteine, lysine, histidine etc.) or oxidation of thiols, which can be reversible or irreversible. In the case of acetaminophen, more than 30 target proteins have been identified and for several of them, corresponding alterations in protein function have been defined in the context of tissue necrosis. Alternatively, protein modification may induce signalling systems which initiate cell death, an immune response or to an altered tissue genotype.

The AmpliChip CYP450 genotyping test: Integrating a new clinical tool

The AmpliChip CYP450 Test, which analyzes patient genotypes for cytochrome P450 (CYP) genes CYP2D6 and CYP2C19, is a major step toward introducing personalized prescribing into the clinical environment. Interest in adverse drug reactions (ADRs), the genetic revolution, and pharmacogenetics have converged with the introduction of this tool, which is anticipated to be the first of a new wave of such tools to follow over the next 5-10 years. The AmpliChip CYP450 Test is based on microarray technology, which combines hybridization in precise locations on a glass microarray and a fluorescent labeling system. It classifies individuals into two CYP2C19 phenotypes (extensive metabolizers [EMs] and poor metabolizers [PMs]) by testing three alleles, and into four CYP2D6 phenotypes (ultrarapid metabolizers [UMs], EMs, intermediate metabolizers [IMs], and PMs) by testing 27 alleles, including seven duplications. CYP2D6 is a metabolic enzyme with four activity levels (or phenotypes): UMs with unusually high activity; normal subjects, known as EMs; IMs with low activity; and PMs with no CYP2D6 activity (7% of Caucasians and 1-3% in other ethnic groups). Levels of evidence for the association between CYP2D6 PMs and ADRs are relatively reasonable and include systematic reviews of case-control studies of some typical antipsychotics and tricyclic antidepressants (TCAs). Evidence for other phenotypes is considerably more limited. The CYP2D6 PM phenotype may be associated with risperidone ADRs and discontinuation due to ADRs. Venlafaxine, aripiprazole, duloxetine, and atomoxetine are newer drugs metabolized by CYP2D6 but studies of the clinical relevance of CYP2D6 genotypes are needed. Non-psychiatric drugs metabolized by CYP2D6 include metoprolol, tamoxifen, and codeine-like drugs. CYP2C19 PMs (3-4% of Caucasians and African Americans, and 14-21% of Asians) may require dose adjustment for some TCAs, moclobemide, and citalopram. Other drugs metabolized by CYP2C19 are diazepam and omeprazole. The future of pharmacogenetics depends on the ability to overcome serious obstacles, including the difficulties of conducting and publishing studies in light of resistance from grant agencies, pharmaceutical companies, and some scientific reviewers. Assuming more studies are published, pharmacogenetic clinical applications may be compromised by economic factors and the lack of physician education. The combination of a US FDA-approved test, such as the AmpliChip CYP450 Test, and an FDA definition of CYP2D6 as a 'valid biomarker' makes CYP2D6 genotyping a prime candidate to be the first successful pharmacogenetic test in the clinical environment. One can use microarray technology to test for hundreds of single nucleotide polymorphisms (SNPs) but, taking into account the difficulties for single gene approaches such as CYP2D6, it is unlikely that very complex pharmacogenetic approaches will reach the clinical market in the next 5-10 years.

Antidepressants and violence: problems at the interface of medicine and law

David Healy and colleagues review several sources of data which suggest an association in a small number of cases between antidepressant treatment and aggression and violence.

Validation of a comprehensive classification tool for treatment-related problems

OBJECTIVE

Several drug-related problem classification systems can be found in the literature. However, it is generally agreed that a comprehensive, well constructed and validated instrument is currently lacking. The aim of this study is the development and validation of a comprehensive treatment-related problems assessment and classification tool for use in teaching, practicing and researching pharmaceutical care and to improve identification, resolving and preventing of treatment-related problems.

METHOD

The development and validation involved five steps starting with literature search to define a treatment related problem and also to form a database of treatment-related problems identified in the literature. In the next step, all problems that were identified in the first step and passed the evaluation of the three authors were pooled together and then divided into groups according to their common or shared construct, in the third step a suitable assessment method was developed according to the construct of the different problems, in the next step the developed instrument was validated for content, internal and external validity. Finally the tool was finalized and tested for reproducibility and inter-rater agreement.

RESULTS

The final validated version included six main categories for treatment-related problems (Indication, Effectiveness, Safety, Knowledge, Adherence and Miscellaneous). These categories include a total of nine subcategories and a total of 29 treatment related problems.

CONCLUSION

The treatment-related problems assessment and classification tool introduced in this paper was applied to actual patient cases and proved to be valid. This tool also has several features that are new.

[Strong suspicion of lung toxicity due to riluzole]

Riluzole is a drug used in the treatment of amyotrophic lateral sclerosis. To date, reports of lung toxicity have been exceptional. We present the case of a 74-year-old man diagnosed with amyotrophic lateral sclerosis. Following 3, 5 months of treatment with riluzole (Rilutek), the patient began to present a clinical picture consisting of nonproductive cough, progressive dyspnea (even with slight exertion), weakness, and radiologic progression with the appearance of predominantly peripheral bilateral pulmonary infiltrates that did not respond to treatment with amoxicillin-clavulanic acid. Bacterial tests did not reveal the presence of germs, nor did other examinations suggest an alternative diagnosis. The patient did not resume treatment with the drug or undergo complementary procedures aimed at obtaining histologic samples. Nevertheless, the coincidence in time, lack of response to antibiotic treatment, remission of symptoms following withdrawal of the drug without initiating any other treatment except 40 mg/d of methylprednisolone for 6 days, absence of alternative diagnoses, and suggestive clinical and radiologic findings all together point to toxicity due to riluzole.

Combination exposure to zidovudine plus sulfamethoxazole-trimethoprim diminishes B-lymphocyte immune responses to Pneumocystis murina infection in healthy mice

We have previously shown that zidovudine plus sulfamethoxazole-trimethoprim exposure decreases immune cell populations in the bone marrow of healthy mice by inducing apoptosis. The hypothesis of the current work was that this toxicity would have an adverse impact on the immune response. To determine this, BALB/c mice were treated with zidovudine, sulfamethoxazole-trimethoprim, the combination of both drugs, or vehicle only (control) via oral gavage for 21 days. On day 4 after dosing completion, the mice were infected intratracheally with 1x10(7) Pneumocystis murina organisms. Immune cell populations (in lung digest, bronchoalveolar lavage fluid, tracheobronchial lymph node, and bone marrow samples), the lung Pneumocystis burden, and serum Pneumocystis-specific antibody titers were determined at days 6, 10, and 20 postinfection. While total bone marrow cellularity was recovered by day 6 postinfection in the combination exposure group, B-cell numbers did not recover until 10 days postinfection, primarily due to the persistent depletion of the late pre-B-cell phenotype. The numbers of CD4+ and CD8+ T cells, as well as the numbers of total B cells and activated B cells in tracheobronchial lymph nodes, were decreased at days 10 and 20 as a result of zidovudine plus sulfamethoxazole-trimethoprim exposure compared to the numbers in the control group. No significant differences in lung lavage or lung digest cell populations were observed. There was a trend of a delay in Pneumocystis clearance in the combination treatment group, and Pneumocystis-specific serum immunoglobulin G titers were reduced at day 20 postinfection. Together, these data indicate that the combination of zidovudine and sulfamethoxazole-trimethoprim adversely affects the humoral immune response to Pneumocystis.

Adverse drug reactions: a cohort study in internal medicine units at a university hospital

OBJECTIVES

Adverse drug reactions (ADRs) are important causes of hospitalization, morbidity and mortality in hospitalized patients. In addition to the impact they have on human life, they also significantly influence health costs. This study intended to (1) identify suspected ADRs and establish their frequency of development, (2) establish a causal relationship with the suspected drug(s) and (3) verify if there is an association between the development of an ADR and factors such as age, gender, number of diagnoses and number of prescribed medications.

METHODS

This cohort study considered hospitalized patients at five inpatient internal medicine units in a university hospital located in southern Brazil. Patients were intensively monitored in order to identify suspected ADRs during hospitalization. The types of reactions were classified and a causal relationship was established using an algorithm.

RESULTS

The cohort study followed 333 patients and approximately 43% of them presented at least one suspected ADR. Three hundred and sixty suspected ADRs were identified, with 19.7% manifesting before the patient was admitted and 80.3% during hospitalization. Medications that were most commonly involved in these suspected cases were anti-infectious agents followed by drugs that act on the central nervous system (CNS). The follow-up length and number of medications in use were independent risk factors for the development of an ADR. The same relationship was not observed for age, gender and number of diagnoses.

CONCLUSION

ADRs are a major problem in our setting and measures must be adopted to minimize them.

Mechanisms of drug-induced delayed-type hypersensitivity reactions in the skin

Cutaneous drug reactions (CDRs) are the most commonly reported adverse drug reactions. These reactions can range from mildly discomforting to life threatening. CDRs can arise either from immunological or nonimmunological mechanisms, though the preponderance of evidence suggests an important role for immunological responses. Some cutaneous eruptions appear shortly after drug intake, while others are not manifested until 7 to 10 days after initiation of therapy and are consistent with delayed-type hypersensitivity. This review discusses critical steps in the initiation of delayed-type hypersensitivity reactions in the skin, which include protein haptenation, dendritic cell activation/migration and T-cell propagation. Recently, an alternative mechanism of drug presentation has been postulated that does not require bioactivation of the parent drug or antigen processing to elicit a drug-specific T-cell response. This review also discusses the role of various immune-mediators, such as cytokines, nitric oxide, and reactive oxygen species, in the development of delayed-type drug hypersensitivity reactions in skin. As keratinocytes have been shown to play a crucial role in the initiation and propagation of cutaneous immune responses, we also discuss the means by which these cells may initiate or modulate CDRs.

Detection of autoantibody to aldolase B in sera from patients with troglitazone-induced liver dysfunction

Troglitazone is a thiazolidinedione antidiabetic agent with insulin-sensitizing activities that was withdrawn from the market in 2000 due to its association with idiosyncratic hepatotoxicity. To address the suspected autoantibody production associated with troglitazone, we investigated autoantibodies in sera from patients with type II diabetes mellitus with troglitazone-induced liver dysfunction. Two female patients (47- and 70-year-old) ceased taking troglitazone (400 mg/day) after 23.5 and 16 weeks, respectively, due to increased serum ALT. Using two-dimensional electrophoresis and amino acid sequence analyses, aldolase B was identified as an autoantigen that reacted with antibodies in sera from both patients. The titer of anti-aldolase B remained high for several weeks after stopping troglitazone administration. The mean reactivity of autoantibodies to aldolase B determined by ELISA with sera of patients with chronic hepatitis (n = 40) and liver cirrhosis (n = 40) was significantly higher (p < 0.05 and p < 0.001, respectively) than with sera of healthy subjects (n = 80). These findings suggest that liver injury may cause the appearance of autoantibodies to aldolase B which may then aggravate the hepatitis. In addition, the anti-aldolase B titer might indicate the severity of liver dysfunction.

Pharmacovigilance program to monitor adverse reactions of recombinant streptokinase in acute myocardial infarction

Background

Streptokinase (SK) is an effective fibrinolytic agent for the treatment of acute myocardial infarction (AMI). The objective of the present study was to assess the adverse drug reactions (ADRs) associated with intravenous recombinant SK in patients with AMI in routine clinical practice.

Methods

A national, prospective and spontaneous reporting-based pharmacovigilance program was conducted in Cuba. Patient demographics, suspected ADR description, elements to define causality, and outcomes were documented and analyzed.

Results

A total of 1496 suspected ADRs identified in 792 patients out of the 1660 (47.7 %) prescriptions reported in the program, were received from July 1995 to July 2002. Most of the patients (71.3%) were male, 67.2% were white and mean age was 61.6 ± 13.0 years. The mean time interval between the onset of symptoms and the start of the SK infusion was 4.9 ± 3.7 h. The most frequently reported ADRs were hypotension, arrhythmias, chills, tremors, vomiting, nauseas, allergy, bleeding and fever. ADR severity was 38% mild, 38% moderate, 10% severe, and 4% very severe. Only 3 patients with hemorrhagic stroke were reported. Seventy-two patients died in-hospital mainly because of cardiac causes associated with the patient's underlying clinical condition. Mortality was 3 times more likely in patients suffering arrhythmias than in those without this event (odds ratio 3.1, 95% CI: 1.8 to 5.1). Most of the reported ADRs were classified as possibly or probably associated with the study medication.

Conclusion

Recombinant SK was associated with a similar post-marketing safety profile to those suggested in previous clinical trials.

Immediate-type allergy to drugs and related compounds: evaluation and management

Adverse drug reactions (ADR) constitute a major health issue in outpatient and inpatient clinical settings. An allergic drug reaction is an immunologically mediated adverse drug reaction that exhibits specificity and recurrence on re-exposure to the offending and/or cross-reactive compound(s). Diagnosis of drug allergy is difficult, as a broad spectrum of different drugs can elicit various immune-mediated diseases with distinct (sometimes unclear) pathomechanism, the exact structure (epitope) that causes the reaction is frequently unknown, the presence of an in vitro or in vivo test results might not be predictive of a clinical situation, and the gold standard or reference test for diagnosis, the drug challenge, is a complicated and sometimes dangerous endeavour. Nevertheless, during the past few years serious attempts have been made to standardise and validate in vitro and in vivo techniques for the diagnosis of drug allergy. New techniques, e.g. flow-assisted analysis of in vitro basophil activation, are replacing older ones like histamine release for immediate-type hypersensitivity reactions. However, additional comprehensive studies are required to further validate the technique and allow its entrance in mainstream diagnostic use, particularly for non-IgE-mediated hypersensitivity. This review attempts to summarize the major causes of immediate hypersensitivity reactions to drugs and related compounds. Special attention is paid to the diagnostic and therapeutic management of this common iatrogenic complication.

Paediatric adverse drug reactions reported in Sweden from 1987 to 2001

PURPOSE

To describe frequency, seriousness and recovery of the patient in reported suspected paediatric adverse drug reactions (ADRs) in Sweden using data from a nation-wide ADR reporting system.

METHODS

Data from ADR reports submitted to the Swedish Medical Products Agency (MPA) were collected from the database SWEDIS and analysed for the period from 1987 to 2001. All reports with certain, probable or possible causality assessments referring to paediatric patients < 16 years of age were included.

RESULTS

In 5771 children an ADR report was documented during the whole 15-year period in a paediatric population of about 1.7 million individuals. The annual reporting frequency was about 385 reports per year. The most frequently reported reactions were application site reaction (24%) followed by fever (12%) and exanthema (6.7%). The clearly most frequently reported group of drugs were the vaccines (63.8%) followed by antibiotics for systemic use (10.1%). The proportion of children that suffered from a serious ADR was 13.0% and that for drug related deaths 0.14%. Nine per cent of the children had not recovered at the time of reporting and 1% recovered with sequelae. A male overrepresentation was observed regarding the total number of reports. About two-third of the reports concerned outpatients less than 4 years of age.

CONCLUSIONS

In respect of the limited number of paediatric drug safety studies or availability of record-linkage databases, nation-wide reporting systems of ADRs represent a valuable hypothesis generating tool in evaluating the characteristics of ADRs occurring in the orphan paediatric population.

Improving the decision-making process in structural modification of drug candidates: reducing toxicity

The rule of three, relating to activity-exposure-toxicity, presents the single most difficult challenge in the design and advancement of drug candidates to the development stage. Absorption, distribution, metabolism and excretion (ADME) studies are widely used in drug discovery to optimize this balance of properties necessary to convert lead compounds into drugs that are both safe and effective for human patients. Idiosyncratic drug reactions (IDRs; referred to as type B reactions, which are mainly caused by reactive metabolites) are one type of adverse drug reaction that is important to human health and safety. This review highlights the strategies for the decision-making process involving substructures that, when found in drugs, can form reactive metabolites and are involved in toxicities in humans; the tools used to reduce IDRs are also discussed. Several examples are included to show how toxicity studies have influenced and guided drug design. Investigations of reactive intermediate formation in subcellular fractions with the use of radiolabeled reagents are also discussed.

Esomeprazole-induced central fever with severe myalgia

OBJECTIVE

To report a case of central fever associated with severe myalgia following esomeprazole.

CASE SUMMARY

A 64-year-old man presented with intense cephalalgia; severe, diffuse myalgia; and fever (>40 degrees C) after esomeprazole initiation for treatment of gastritis. Five hours after ingestion of the first esomeprazole pill (40 mg), the patient developed fever associated with cephalalgia and myalgia. This condition lasted about 40 hours and disappeared spontaneously. Symptoms partially responded to acetaminophen. Four days later, the patient received a second dose of esomeprazole 40 mg. Subsequently, 4 hours later, fever (>40 degrees C), headache, and difficulty in the movement of all parts of the body recurred. Neurologic examination was negative except for a minor state of disorientation. All reflexes were normal or slightly decreased. No skin lesions or breathing difficulty was noted. Routine blood tests were normal. Again, symptoms resolved spontaneously about 40 hours later.

DISCUSSION

The temporal connection between esomeprazole intake and the onset of fever suggests a probable causal link, as confirmed by the Naranjo probability scale. However, the pathogenic mechanism remains unclear. Considering that esomeprazole is able to cross the blood-brain barrier, its peak serum concentration is reached 90-180 minutes after oral administration, and its serum half-life is approximately 2 hours, we assume that the appearance of fever with accompanying neurologic and muscular symptoms might result from the drug interference with the hypothalamic regulatory center of body temperature.

CONCLUSIONS

Hyperpyrexia of central origin associated with intense cephalalgia and myalgia may occur as an adverse effect of esomeprazole therapy.

Pharmacogenetics, ethical issues: review of the Nuffield Council on Bioethics Report

In September this year the Nuffield Council on Bioethics held a meeting to disclose and discuss the main findings of their newly published report on the ethical issues associated with developments in pharmacogenetics research. The basics of pharmacogenetics science is briefly outlined, and then the extent to which the report was successful in addressing (or at least highlighting) the attendant social, ethical, and policy implications of pharmacogenetics research is evaluated.

Hospital-based intensive monitoring of antibiotic-induced adverse events in a university hospital

Hospital-based monitoring is one of the methods used to collect data about drug prescriptions and adverse events. The aim of this 20-day observational prospective study was to evaluate the frequency and type of adverse reaction to antibiotics, and predisposing risk factors in inpatients in six departments of a university hospital (ophthalmology, paediatrics, internal medicine, general surgery, infectious diseases, anaesthesiology and intensive care). The data on all inpatients undergoing antibiotic treatment were collected by physicians trained by our team and validated by an expert panel. Data were recorded on pre-formatted confidential cards (MIO-card). In the 171 inpatients evaluated (125 adults: 39.5% male, mean age 61.6 years, range 21-93; and 46 children: 50% male; mean age 4.75 years, range 3 months-12 years), cefazolin (19.9%), chloramphenicol (18.6%), ceftriaxone (15.4%) and netilmicin (12.9%) were the most frequently used antibiotics. Adverse events occurred in four adults and three children: one had leucopenia (trimethoprim/sulfamethoxazole), one nephrotoxicity (netilmicin+teicoplanin) and one nephrotoxicity (cefotaxime), one diarrhoea (ceftriaxone), one neurotoxicity (isoniazid), one angioneurotic oedema (piperacillin) and one skin rashes (ceftriaxone). A number of strategies (educative and persuasive, facilitative and restrictive) have been proposed to improve antibiotic use. Our study suggests that hospital-based monitoring is a good method with which to detect links between drug exposure and adverse drug reactions in children and adults.

Physicians??? Attitudes and Adverse Drug Reaction Reporting

OBJECTIVES

Voluntary adverse drug reaction (ADR) reporting is fundamental to medical drug safety surveillance; however, substantial under-reporting exists and is the main limitation of the system. This study sought to identify the knowledge- and attitude-related factors associated with ADR reporting by physicians in Northern Portugal.

METHODS

Case-control study covering a population of National Health Service medical practitioners. The 88 cases comprised physicians who had reported at least one ADR to the drug surveillance unit from the year 2000 to the date of enrolment in the study. The 771 controls were randomly selected from among the remaining physicians. All interviews were conducted using a self-administered questionnaire. Knowledge and attitudes regarding spontaneous ADR reporting were based on Inman's 'seven deadly sins'. Agreement with the questions included in the questionnaire was measured using a horizontal, continuous visual analogue scale, which was unnumbered. Recorded answers were read in a range from zero (total disagreement) to ten (total agreement). We used logistic regression to determine the ADR reporting adjusted odds ratio (ORadj) for a change in exposure corresponding to the interquartile range for each attitude.

RESULTS

A total of 397 questionnaires were received from 731 eligible practitioners (54.3%). Physicians who worked in primary versus hospital care (ORadj 7.74 [95% CI 1.85, 32.30]) and in general medicine (ORadj 1.05 [95% CI 0.30, 3.69]) versus medical specialities were more likely to report ADRs. In contrast, physicians working in the medical-surgical/surgical fields were significantly less likely to report ADRs compared with medical specialists (ORadj 0.10 [95% CI 0.02, 0.46]). Attitudes to ADRs were strongly associated with reporting probability. Hence, an interquartile decrease in any of the following attitudes increased the probability of reporting by: (i) 87% (p < 0.05) for complacency (the belief that really serious ADRs are well documented by the time a drug is marketed); (ii) 109% (p < 0.01) for insecurity (the belief that it is nearly impossible to determine whether a drug is responsible for a particular adverse reaction); (iii) 143% (p < 0.001) for diffidence (the belief that one would only report an ADR if one were sure that it was related to the use of a particular drug); (iv) 220% (p < 0.001) for indifference (the belief that the one case an individual doctor might see could not contribute to medical knowledge); and (v) 71% (p < 0.05) for ignorance (the belief that it is only necessary to report serious or unexpected ADRs).

CONCLUSION

This study shows that there are attitudes strongly associated with under-reporting. The implementation of purpose-designed educational interventions based on the attitudes identified in this study may serve to improve reporting substantially.