Showing papers in "Drug Safety in 2006"

Under-reporting of adverse drug reactions : a systematic review.

Abstract: The purpose of this review was to estimate the extent of under-reporting of adverse drug reactions (ADRs) to spontaneous reporting systems and to investigate whether there are differences between different types of ADRs. A systematic literature search was carried out to identify studies providing a numerical estimate of under-reporting. Studies were included regardless of the methodology used or the setting, e.g. hospital versus general practice. Estimates of under-reporting were either extracted directly from the published study or calculated from the study data. These were expressed as the percentage of ADRs detected from intensive data collection that were not reported to the relevant local, regional or national spontaneous reporting systems. The median under-reporting rate was calculated across all studies and within subcategories of studies using different methods or settings. In total, 37 studies using a wide variety of surveillance methods were identified from 12 countries. These generated 43 numerical estimates of under-reporting. The median under-reporting rate across the 37 studies was 94% (interquartile range 82-98%). There was no significant difference in the median under-reporting rates calculated for general practice and hospital-based studies. Five of the ten general practice studies provided evidence of a higher median under-reporting rate for all ADRs compared with more serious or severe ADRs (95% and 80%, respectively). In comparison, for five of the eight hospital-based studies the median under-reporting rate for more serious or severe ADRs remained high (95%). The median under-reporting rate was lower for 19 studies investigating specific serious/severe ADR-drug combinations but was still high at 85%. This systematic review provides evidence of significant and widespread under-reporting of ADRs to spontaneous reporting systems including serious or severe ADRs. Further work is required to assess the impact of under-reporting on public health decisions and the effects of initiatives to improve reporting such as internet reporting, pharmacist/nurse reporting and direct patient reporting as well as improved education and training of healthcare professionals.

Clarification of terminology in medication errors: definitions and classification.

Abstract: We have previously described and analysed some terms that are used in drug safety and have proposed definitions. Here we discuss and define terms that are used in the field of medication errors, particularly terms that are sometimes misunderstood or misused. We also discuss the classification of medication errors. A medication error is a failure in the treatment process that leads to, or has the potential to lead to, harm to the patient. Errors can be classified according to whether they are mistakes, slips, or lapses. Mistakes are errors in the planning of an action. They can be knowledge based or rule based. Slips and lapses are errors in carrying out an action - a slip through an erroneous performance and a lapse through an erroneous memory. Classification of medication errors is important because the probabilities of errors of different classes are different, as are the potential remedies.

Adverse drug reaction-related hospitalisations: a nationwide study in The Netherlands.

Abstract: Background: The incidence of adverse drug reaction (ADR)-related hospitalisations has usually been assessed within hospitals. Because of the variability in results and methodology, it is difficult to extrapolate these results to a national level.

Pharmacokinetic drug interaction profiles of proton pump inhibitors.

Abstract: Proton pump inhibitors are used extensively for the treatment of gastric acid-related disorders because they produce a greater degree and longer duration of gastric acid suppression and, thus, better healing rates, than histamine H2 receptor antagonists. The need for long-term treatment of these disorders raises the potential for clinically significant drug interactions in patients receiving proton pump inhibitors and other medications. Therefore, it is important to understand the mechanisms for drug interactions in this setting. Proton pump inhibitors can modify the intragastric release of other drugs from their dosage forms by elevating pH (e.g. reducing the antifungal activity of ketoconazole). Proton pump inhibitors also influence drug absorption and metabolism by interacting with adenosine triphosphate-dependent P-glycoprotein (e.g. inhibiting digoxin efflux) or with the cytochrome P450 (CYP) enzyme system (e.g. decreasing simvastatin metabolism), thereby affecting both intestinal first-pass metabolism and hepatic clearance. Although interactions based on the change of gastric pH are a group-specific effect and thus may occur with all proton pump inhibitors, individual proton pump inhibitors differ in their propensities to interact with other drugs and the extent to which their interaction profiles have been defined. The interaction profiles of omeprazole and pantoprazole have been studied most extensively. A number of studies have shown that omeprazole carries a considerable potential for drug interactions, since it has a high affinity for CYP2C19 and a somewhat lower affinity for CYP3A4. In contrast, pantoprazole appears to have lower potential for interactions with other medications. Although the interaction profiles of esomeprazole, lansoprazole and rabeprazole have been less extensively investigated, evidence suggests that lansoprazole and rabeprazole seem to have a weaker potential for interactions than omeprazole. Although only a few drug interactions involving proton pump inhibitors have been shown to be of clinical significance, the potential for drug interactions should be taken into account when choosing a therapy for gastric acid-related disorders, especially for elderly patients in whom polypharmacy is common, or in those receiving a concomitant medication with a narrow therapeutic index.

Second-generation antipsychotics: is there evidence for sex differences in pharmacokinetic and adverse effect profiles?

Abstract: Six second-generation antipsychotics (SGAs), aripiprazole, clozapine, olanzapine, quetiapine, risperidone and ziprasidone, are currently US FDA approved. The aim of this review is to investigate whether sex differences exist for efficacy and adverse effects of these drugs.

Influence of pharmacists' attitudes on adverse drug reaction reporting : a case-control study in Portugal.

Abstract: Introduction: Pharmacists can play a fundamental role in adverse drug reaction (ADR) reporting, although the factors that affect underreporting among these professionals are unknown. The objectives of this study were to identify (i) professional or demographic characteristics; and (ii) attitudes associated with pharmacists’ ADR reporting in northern Portugal.

Prevalence of the diabetes, metabolic syndrome and metabolic abnormalities in schizophrenia over the course of the illness: a cross-sectional study

Abstract: BACKGROUND Patients with schizophrenia are at high risk of developing metabolic abnormalities. METHOD A prospective study focusing on metabolic disturbances in patients with schizophrenia, including an oral glucose tolerance test, is currently ongoing at our University Hospital and affiliate services. The prevalence of metabolic abnormalities at baseline was assessed in a cohort of 415 patients with schizophrenia. The sample was divided into 4 groups according to duration of illness: first-episode patients (<1.5 years), recent-onset patients (between 1.5 and 10 years), subchronic patients (between 10 and 20 years) and chronic patients (>20 years). RESULTS Metabolic abnormalities were already present in first-episode patients, and considerably increased with increasing duration of illness. When compared to the general population matched for age and gender, much higher rates of the metabolic syndrome (MetS) and diabetes were observed for patients with schizophrenia. For MetS, the increase over time was similar to that of the general population. In contrast, the difference in the prevalence of diabetes in patients with schizophrenia and the general population dramatically and linearly increased from 1.6% in the 15-25 age-band to 19.2% in the 55-65 age-band. CONCLUSION Thus, the current data suggest that on the one hand metabolic abnormalities are an inherent part of schizophrenic illness, as they are already present in first-episode patients. On the other hand, however, our results suggest a direct effect of the illness and/or antipsychotic medication on their occurrence. The data underscore the need for screening for metabolic abnormalities in patients diagnosed with schizophrenia, already starting from the onset of the illness.

Safety of Drug Therapies Used for Weight Loss and Treatment of Obesity

Abstract: Some of the medications used for weight loss in the management of obesity have been associated with unacceptable morbidity and mortality. Safety concerns have led to the withdrawal of aminorex, followed by the fenfluramines in 1997, and phenylpropanolamine (norephedrine) in 2000. Aminorex was associated with an increased prevalence of primary pulmonary hypertension (PPH), fenfluramines with an increased prevalence of PPH and valvulopathy, and phenylpropanolamine with an increased risk of haemorrhagic stroke. Several studies have investigated the safety of the fenfluramines, yet the benefit-risk profile has not been conclusively quantified. This is due to several deficiencies in the published studies, including a lack of data on the baseline prevalences of comorbid conditions in obese subjects, and potential confounders and biases in the study designs. Although several studies and systematic reviews support an increased risk of PPH and valvulopathy in patients who have taken fenfluramines, without knowledge of the background prevalence it is not possible to determine if the exposure preceded the outcome. The population at higher risk of these adverse effects includes those taking higher doses or with a longer duration of exposure to fenfluramines and those with pre-existing cardiac disease or a genetic predisposition. Patients exposed to fenfluramines continue to be monitored, with some follow-up studies indicating no overall worsening in valvulopathy over time. There are limited efficacy and safety data for amfepramone (diethylpropion) and phentermine and their approval for the management of obesity is limited to short-term use. Orlistat and sibutramine are the only currently approved medications for long-term management of obesity. Although the benefit-risk profiles of sibutramine and orlistat appear positive, sibutramine continues to be monitored because of long-term safety concerns. The safety and efficacy of currently approved drug therapies have not been evaluated in children and elderly patient populations and there is limited information in adolescents, whilst the long-term safety of current and potential new drug therapies in adults will require several years of postmarketing surveillance to fully elucidate their adverse effect profiles.

Camptothecin and podophyllotoxin derivatives : Inhibitors of topoisomerase I and II - mechanisms of action, pharmacokinetics and toxicity profile

Abstract: Camptothecins represent an established class of effective agents that selectively target topoisomerase I by trapping the catalytic intermediate of the topoisomerase I-DNA reaction, the cleavage complex. The water-soluble salt camptothecin-sodium - introduced in early trials in the 1960s - was highly toxic in animals, whereas the semisynthetic derivatives irinotecan and topotecan did not cause haemorrhagic cystitis because of their higher physicochemical stability and solubility at lower pH values. Myelosuppression, neutropenia and, to a lesser extent, thrombocytopenia are dose-limiting toxic effects of topotecan. In contrast to the structurally-related topotecan, irinotecan is a prodrug which has to be converted to SN-38, its active form. SN-38 is inactivated by conjugation, thus patients with Gilbert's syndrome and other forms of genetic glucuronidation deficiency are at an increased risk of irinotecan-induced adverse effects, such as neutropenia and diarrhoea. The cytotoxic mechanism of podophyllotoxin is the inhibition of topoisomerase II. Common adverse effects of etoposide include dose-limiting myelosuppression. Hypersensitivity reactions are more common with etoposide and teniposide than with etoposide phosphate because the formulations of the former contain sensitising solubilisers. Leukopenia and thrombocytopenia occur in 65% and 80%, respectively, of patients after administration of conventional doses of teniposide. Anorexia, vomiting and diarrhoea are generally of mild severity after administration of conventional doses of topoisomerase II inhibitors. Clinical pharmacokinetic studies have revealed substantial interindividual variabilities regarding the area under the concentration-time curve values and steady-state concentrations for all drugs reviewed in this article. Irinotecan, etoposide and teniposide are degraded via complex metabolic pathways. In contrast, topotecan primarily undergoes renal excretion. Regarding etoposide and teniposide, the extent of catechol formation over time during drug metabolism may be associated with a higher risk for secondary malignancies.

NSAID-associated adverse effects and acid control aids to prevent them: a review of current treatment options.

Abstract: NSAIDs are central to the clinical management of a wide range of conditions. However, NSAIDs in combination with gastric acid, which has been shown to play a central role in upper gastrointestinal (GI) events, can damage the gastroduodenal mucosa and result in dyspeptic symptoms and peptic lesions such as ulceration.

Evidence of tendinitis provoked by fluoroquinolone treatment: a case-control study.

Abstract: Objective: To investigate the association between the use of fluoroquinolone agents and the risk of tendinitis in a large population-based case-control study. Methods: The study was performed by linking automated health databases from the Region of Lombardia, Italy. Cases were patients aged ≥18 years who had a hospital discharge diagnosis of non-traumatic tendinitis in 2002–3. For each case, up to five controls were randomly selected among those eligible for inclusion in the study. A conditional logistic regression model was used to estimate the odds ratio of tendinitis associated with the current, recent and past use of fluoroquinolones. Odds ratios were adjusted for exposure to other antibacterials and other drugs. Results: 22 194 cases and 104 906 controls met the inclusion criteria. Current use of fluoroquinolones significantly increased the risk of tendon disorders as a whole (odds ratio [OR] = 1.7; 95% CI 1.4, 2.0), tendon rupture (OR = 1.3; 95% CI 1.0, 1.8) and rupture of the Achilles’ tendon (OR = 4.1; 95% CI 1.8, 9.6). Concomitant use of corticosteroids and fluoroquinolones increased the risk of both tendon rupture (OR = 3.1; 95% CI 1.5, 6.3) and rupture of the Achilles’ tendon (OR = 43.2; 95% CI 5.5, 341.1). Discussion: Evidence that exposure to fluoroquinolones is associated with the sudden occurrence of tendinitis is supported by this large population-based study. We can estimate that a single case of rupture of the Achilles’ tendon would occur for every 5958 persons treated with fluoroquinolones (95% CI 2148, 23 085). The corresponding number needed to harm is 979 (95% CI 122, 9172) for patients who concomitantly use corticosteroids and 1638 (95% CI 351, 8843) for those aged >60 years. Conclusion: Clinicians should be aware of this adverse effect, and the increased risk for fluoroquinolone-associated tendinitis in elderly patients with corticosteroid use must be considered when these agents are prescribed.

Heart Failure Induced by Non-Cardiac Drugs

Abstract: Although heart failure is predominantly caused by cardiovascular conditions such as hypertension, coronary heart disease and valvular heart disease, it can also be an adverse reaction induced by drug therapy. In addition, some drugs have the propensity to adversely affect haemodynamic mechanisms in patients with an already existing heart condition. In this article, non-cardiac drugs known to be associated with the development or worsening of heart failure are reviewed. Moreover, drugs that may adversely affect the heart as a pump without causing symptoms or signs of heart failure are also included.

Long-term treatment with atypical antipsychotics and the risk of weight gain : a literature analysis.

Abstract: The aim of this review is to analyse and summarise the literature data about the incidence of weight gain in patients exposed to atypical antipsychotics during long-term (≥1 year) treatment regimens. Despite the clinical relevance of the topic, the vast majority of reviewed studies showed methodological limitations. Some trials had retrospective analysis, and concomitant medications also associated with an increased risk of weight gain, such as antidepressants and mood stabilisers, were often prescribed. Results were obtained from clinical trials conducted using flexible dosages; thus, the relationship between dosage and weight change was not explored adequately. Also, in a large number of studies, the average antipsychotic daily dose was lower than the usual dosage in clinical practice. Moreover, weight gain was evaluated by different measures, such as mean weight gain in the enrolled population, percentage of patients who gained >7% of basal weight or body mass index (BMI) variations from baseline.

Safety of inhalation of a 50% nitrous oxide/oxygen premix: a prospective survey of 35 828 administrations.

Abstract: Background: A 50% nitrous oxide/oxygen (N2O/O2) premix is widely used to alleviate pain or anxiety during brief care procedures in various medical domains. In some countries, recent changes in regulation status for medical gases state that they should be considered as drugs. Consequently, more valuable data gained from exhaustive clinical surveys are needed. This prospective study, conducted in the same conditions imposed for testing a drug, aims to analyse the factors that affect tolerance of the 50% N2O/O2 premix in a wide range of clinical indications.

Therapeutic Drug Monitoring and Pharmacogenetic Tests as Tools in Pharmacovigilance

Abstract: 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.

Temporal relationship between use of NSAIDs, including selective COX-2 inhibitors, and cardiovascular risk.

Abstract: Background and Objective: The search for NSAIDs with less gastrointestinal toxicity led to the introduction of the selective cyclo-oxygenase-2 (COX-2) inhibitors. However, following their introduction into the market, concerns have developed regarding their safety, particularly their cardiovascular safety. The purpose of this study was to assess the cardiovascular risk (events included were myocardial infarction, stroke and myocardial infarction-related deaths) associated with long-term (>180 days of exposure) and short-term (≤180 days of exposure) use of non-selective NSAIDs, including ‘preferential COX-2 inhibitors’ (i.e. etodolac, nabumetone and salsalate), and selective COX-2 inhibitors.

Comparative performance of two quantitative safety signalling methods: implications for use in a pharmacovigilance department.

Abstract: Background and objectives: There is increasing interest in using disproportionality-based signal detection methods to support postmarketing safety surveillance activities. Two commonly used methods, empirical Bayes multi-item gamma Poisson shrinker (MGPS) and proportional reporting ratio (PRR), perform differently with respect to the number and types of signals detected. The goal of this study was to compare and analyse the performance characteristics of these two methods, to understand why they differ and to consider the practical implications of these differences for a large, industry-based pharmacovigilance department. Methods: We compared the numbers and types of signals of disproportionate reporting (SDRs) obtained with MGPS and PRR using two postmarketing safety databases and a simulated database. We recorded signal counts and performed a qualitative comparison of the drug-event combinations signalled by the two methods as well as a sensitivity analysis to better understand how the thresholds commonly used for these methods impact their performance. Results: PRR detected more SDRs than MGPS. We observed that MGPS is less subject to confounding by demographic factors because it employs stratification and is more stable than PRR when report counts are low. Simulation experiments performed using published empirical thresholds demonstrated that PRR detected false-positive signals at a rate of 1.1%, while MGPS did not detect any statistical false positives. In an attempt to separate the effect of choice of signal threshold from more fundamental methodological differences, we performed a series of experiments in which we modified the conventional threshold values for each method so that each method detected the same number of SDRs for the example drugs studied. This analysis, which provided quantitative examples of the relationship between the published thresholds for the two methods, demonstrates that the signalling criterion published for PRR has a higher signalling frequency than that published for MGPS. Discussion and conclusion: The performance differences between the PRR and MGPS methods are related to (i) greater confounding by demographic factors with PRR; (ii) a higher tendency of PRR to detect false-positive signals when the number of reports is small; and (iii) the conventional thresholds that have been adapted for each method. PRR tends to be more ‘sensitive’ and less ‘specific’ than MGPS. A high-specificity disproportionality method, when used in conjunction with medical triage and investigation of critical medical events, may provide an efficient and robust approach to applying quantitative methods in routine postmarketing pharmacovigilance.

Effect of ezetimibe and/or simvastatin on coenzyme Q10 levels in plasma : A randomised trial

Abstract: Background: HMG-CoA reductase inhibitors (‘statins’) have been associated with a decrease in ubidecarenone (ubiquinone) levels, a lipophilic enzyme also known as coenzyme Q10 (CoQ10), due to inhibition of mevalonate synthesis. There is speculation that a decrease in CoQ10 levels may be associated with statin-induced myopathy. The cholesterol absorption inhibitor ezetimibe increases endogenous cholesterol synthesis. The purpose of this study was to examine (i) the effects of ezetimibe and simvastatin on plasma CoQ10 levels and (ii) whether ezetimibe coadministered with simvastatin abrogates the suggested statin-induced decrease in the CoQ10 plasma levels.

Interventions of hospital pharmacists in improving drug therapy in children: a systematic literature review.

Abstract: Medicines' management or pharmaceutical care in paediatric patients is particularly demanding, mainly because the majority of available drugs have been developed for use in adults. As a result, in children, drugs are often unlicensed or used off-label, suitable formulations or appropriate strengths are lacking, and drugs have to be extemporaneously prepared, liquids and injections diluted, and tablets split. These factors increase the likelihood of medication errors and may lead to a reduction in drug effect. Age-specific changes in pharmacokinetics and pharmacodynamics further complicate drug therapy in children. All these challenges provide unique opportunities for pharmacists to improve the quality of care for paediatric patients. We conducted a systematic literature review examining whether the interventions of hospital pharmacists improve drug therapy in children. Several medical and pharmaceutical databases were searched systematically to identify articles investigating hospital pharmacists' interventions that were intended to improve drug therapy in children. Inclusion criteria were English language, primary research papers and studies in which clinical pharmacists contributed directly to patient care. Exclusion criteria were reviews, editorials, questionnaire studies, modelling studies, letters and studies only available in abstract form. This systematic search identified 18 articles documenting the role of a clinical hospital pharmacist in paediatric care. These articles were divided into the following groups based on study type: (i) studies documenting interventions made by pharmacists and their role in inpatients; (ii) articles presenting the outcomes of a satellite pharmacy; and (iii) articles examining pharmacist involvement in paediatric outpatient clinics. No randomised study comparing pharmacist interventions with standard care was found. In conclusion, although it was difficult to compare the various studies identified because of the different settings, design, duration, size, methodology and definition, all these studies highlighted the importance of hospital pharmacists to medicines' management in paediatric patients. On the basis of this review, we can conclude that pharmacist reviewing of medication charts is very important in identifying medication errors; hence, it is likely to be the most effective method of improving drug therapy in children.

Neuropsychiatric complications of antiretroviral therapy.

Abstract: Neuropsychiatric adverse effects related to potent antiretroviral therapy are among the complications that can lead to poor adherence, treatment interruptions, or change of antiretroviral therapy regimens. For a historical perspective, we review early literature and case reports with CNS adverse effects attributed to antiretrovirals. The variability of the cerebrospinal fluid penetration of individual antiretrovirals may contribute to their potential for behavioural and psychiatric manifestations. The majority of neuropsychiatric complications related to potent antiretroviral therapy have been associated with the use of the efavirenz. Updates on the risk of neuropsychiatric manifestations with efavirenz use in patients with a history of psychiatric disorders or substance abuse are reviewed. We include a critical review of recently published data on the long-term CNS adverse effects with efavirenz. Special attention is given to the results of recent investigations on the relationship between the pharmacogenomics of genes responsible for efavirenz metabolism and the plasma concentration of efavirenz. It is important to note that there is no established direct correlation of efavirenz concentrations and symptoms. It is not recommended for practitioners to adjust efavirenz doses in order to prevent or alleviate CNS adverse effects. Patients may be placed at risk for virological failure and resistance if they receive suboptimal doses of efavirenz. The aim of this article is to give a concise review and an update on recent literature concerning neuropsychiatric effects of antiretroviral use in HIV-infected patients. Our intent is to present practitioners with data that can be used in a practical way to both educate and improve outcomes in the HIV-infected patient population.

Adverse-event profile of Crataegus spp.: a systematic review.

Abstract: Crataegus spp. (hawthorn) monopreparations are predominantly used for treating congestive heart failure. The effectiveness of hawthorn preparations (flowers with leaves; berries) is documented in a number of clinical studies, reviews and meta-analyses. The aim of this article is to assess the safety data of all available human studies on hawthorn monopreparations. Systematic searches were conducted on MEDLINE, EMBASE, AMED, The Cochrane Library, the UK National Research Register and the US ClinicalTrials.gov (up to January 2005). Data were requested from the spontaneous reporting scheme of the WHO. Hand searches were also conducted in a sample of relevant medical journals, conference proceedings, reference lists of identified articles and our own files. Eight manufacturers of hawthorn-containing preparations were contacted and asked to supply any information on adverse events or drug interactions. Data from all clinical studies and reports were assessed. Only human studies on monopreparations were included. Data from hawthorn-containing combination preparations and homeopathic preparations were excluded. All studies were read and evaluated by one reviewer and independently verified by at least one additional reviewer. Twenty-nine clinical studies were identified, of which 24 met our inclusion criteria. A total of 7311 patients were enrolled, and data from 5577 patients were available for analysis. The daily dose and duration of treatment with hawthorn monopreparations ranged from 160 to 1800mg and from 3 to 24 weeks, respectively. The extracts most used in the clinical trials were WS 1442 (extract of hawthorn standardised to 18.75% oligomeric procyanidins) and LI 132 (extract of hawthorn standardised to 2.25% flavonoids). Overall, 166 adverse events were reported. Most of these adverse events were, in general, mild to moderate; eight severe adverse events have been reported with the LI 132 extract. The most frequent adverse events were dizziness/vertigo (n = 15), gastrointestinal complaints (n = 24), headache (n = 9), migraine (n = 8) and palpitation (n = 11). The WHO spontaneous reporting scheme received 18 case reports. In the identified trials, the most frequent adverse events were dizziness (n = 6), nausea (n = 5), fall (n = 2), gastrointestinal haemorrhage (n = 2), circulation failure (n = 2) and erythematous rash (n = 2). There were no reports of drug interactions. In conclusion, all data reviewed in this article seem to indicate that hawthorn is well tolerated even if some severe adverse events were reported; this suggests that further studies are needed to better assess the safety of hawthorn-containing preparations. Moreover, the unsupervised use of this drug can be associated with problems, especially if given with concomitant medications.

The prevalence of potential drug-drug interactions in patients with heart failure at hospital discharge.

Abstract: Background/objective: Pharmacotherapy for heart failure is complex and, due to polypharmacy, is associated with a large risk of potential drug-drug interactions (DDIs). The objective of the present study was to assess the prevalence of potential DDIs in the medication of hospitalised heart failure patients and to evaluate their clinical relevance.

Interactions between antiepileptic and antipsychotic drugs.

Abstract: Antiepileptic and antipsychotic drugs are often prescribed together. Interactions between the drugs may affect both efficacy and toxicity. This is a review of human clinical data on the interactions between the antiepileptic drugs carbamazepine, valproic acid (sodium valproate), vigabatrin, lamotrigine, gabapentin, topiramate, tiagabine, oxcarbazepine, levetiracetam, pregabalin, felbamate, zonisamide, phenobarbital and phenytoin with the antipsychotic drugs risperidone, olanzapine, quetiapine, clozapine, amisulpride, sulpiride, ziprasidone, aripiprazole, haloperidol and chlorpromazine; the limited information on interactions between antiepileptic drugs and zuclopenthixol, periciazine, fluphenazine, flupenthixol and pimozide is also presented. Many of the interactions depend on the induction or inhibition of the cytochrome P450 isoenzymes, but other important mechanisms involve the uridine diphosphate glucuronosyltransferase isoenzymes and protein binding. There is some evidence for the following effects. Carbamazepine decreases the plasma concentrations of both risperidone and its active metabolite. It also decreases concentrations of olanzapine, clozapine, ziprasidone, haloperidol, zuclopenthixol, flupenthixol and probably chlorpromazine and fluphenazine. Quetiapine increases the ratio of carbamazepine epoxide to carbamazepine and this may lead to toxicity. The data on valproic acid are conflicting; it may either increase or decrease clozapine concentrations, and it appears to decrease aripiprazole concentrations. Chlorpromazine possibly increases valproic acid concentrations. Lamotrigine possibly increases clozapine concentrations. Phenobarbital decreases clozapine, haloperidol and chlorpromazine concentrations. Phenytoin decreases quetiapine, clozapine, haloperidol and possibly chlorpromazine concentrations. There are major gaps in the data. In many cases there are no published clinical data on interactions that would be predicted on theoretical grounds.

Reye's syndrome: the case for a causal link with aspirin.

Abstract: Reye's syndrome is a serious, acute encephalopathy that has been linked with aspirin (acetylsalicylic acid) use in children and teenagers <18 years of age. Although others may disagree, it is my belief that any objective analysis of published material in the last 20 years must conclude that there is a close link between the devastating encephalopathy Reye's syndrome and ingestion of aspirin during the febrile prodrome. The drug appears to act as a co-factor in susceptible individuals. Although some of the epidemiological data indicate an association between the two, the burden of evidence suggests actual causality and is both consistent and specific as well as strong and time related. Some of the evidence points to illness severity being dose related although it seems that in the presence of a viral infection, no dose of aspirin can be considered safe. No published work, using methodology that can be critically evaluated, has shown evidence to contradict these conclusions and they have been widely accepted. Since government health warnings were appended to aspirin-containing formulations, the decline in case numbers on both sides of the Atlantic has been nothing short of remarkable. Recent in vitro findings have pinpointed the site of action of the drug on the long chain hydroxyacyl-CoA dehydrogenase enzyme (a component of the mitochondrial trifunctional enzyme) and, even at therapeutic concentrations, oxidation is impaired in cultured fibroblasts from patients who have recovered from the disorder. This is quite unlike that seen in cells from normal controls. Even when major influenza outbreaks occur in the future, Reye's syndrome is preventable provided government health warnings are heeded and the cogent evidence set forth here is acted upon by the parents of feverish children and self-medicating teenagers.

Current Understanding of Contrast Media Reactions and Implications for Clinical Management

Abstract: Iodinated contrast media (CM) are an integral part of modern diagnostic medicine. Although these agents are considered to be relatively safe, adverse effects in the form of allergy-like reactions occur in a significant number of exposed patients. These reactions may be divided into immediate and delayed responses. Immediate (within 1 hour of administration) anaphylactic reactions range from urticaria and angioedema to laryngeal oedema, hypotension and even death. Delayed reactions to CM occur from 1 hour to 1 week after administration and usually have mostly cutaneous manifestations. History of prior CM reactions and atopy predispose patients to CM reactions. Despite intense research into the pathogenesis of the immediate anaphylactoid responses, new evidence shows that true IgE type I hypersensitivity mediation occurs only in rare, severe cases. The aetiology appears to be multifactorial in most individuals. There is strong evidence to conclude that type IV hypersensitivity is responsible for the delayed reactions to CM. Although switching to non-ionic agents significantly reduces the incidence of immediate reactions to CM, there is little consensus regarding corticosteroid prophylaxis in high-risk individuals. Skin testing and provocative challenges also provide little security. Therefore, physicians must be better prepared to treat immediate anaphylactoid responses. Preventing delayed CM reactions is best performed with patch and delayed intradermal testing in those with a history of prior reactions, although false-negative results have been reported. Corticosteroids and antihistamines may be required for treatment. Until newer agents are developed that negate these issues, healthcare providers must strive to better understand the risk factors associated with CM reactions, as well as the available prophylactic and treatment options.

Botulinum toxin treatment of adult spasticity : a benefit-risk assessment.

Abstract: Injections of botulinum toxin have revolutionised the treatment of focal spasticity. Before their advent, the medical treatment for focal spasticity involved oral anti-spasticity drugs, which had decidedly non-focal adverse effects, and phenol injections. Phenol injections could be difficult to perform, could cause sensory complications and had effects that were of uncertain duration and magnitude. Furthermore, few neurologists knew how to perform them as they were mostly the province of rehabilitation specialists. Botulinum toxin can produce focal, controllable muscle weakness of predictable duration, without sensory adverse effects. Randomised clinical trials (RCTs) involving patients with spasticity resulting from a variety of diseases (mainly stroke and multiple sclerosis) have clearly shown that botulinum toxin type A (Dysport and Botox) can temporarily (for approximately 3 months) reduce spastic hypertonia in the elbow, wrist and finger flexors of the upper limbs, and the hip adductors and ankle plantar flexors in the lower limbs. The clinical benefits from this reduction of neurological impairment are best shown in the upper limb, with less disability of passive function and reduced caregiver burden. In the lower limbs, there is improved perineal hygiene from hip adductor injections. The benefits of reducing ankle plantar flexor tone are less well established. Pain is also reduced, possibly by mechanisms other than muscle weakness. Improved active function has not yet been clearly demonstrated in RCTs, only in open-label trials. The safety of botulinum toxin-A is impressive, with minimal (mainly local) adverse effects. There are little data on the use of botulinum toxin type B (Myobloc or Neurobloc) in spasticity and the only RCT that has examined this did not show tone reduction; dry mouth appeared to be a very common adverse effect. There are also very little data to allow a benefit-risk comparison of phenol and botulinum toxin injections; each have their clinical and technical advantages and disadvantages, and phenol is much less costly than botulinum toxin.

Herbal medicines used during the first trimester and major congenital malformations: an analysis of data from a pregnancy cohort study.

Abstract: Background: Major congenital malformations place a considerable burden on the affected child, the family and society. Any kind of medicine used during pregnancy might have a harmful impact; therefore, such practice has raised concerns. The objective of the current study was to explore the relationship between the use of herbal medicines by pregnant women during the first trimester of pregnancy and the risk of major congenital malformation in their live born infants. Methods: This was a cross-sectional analysis of data from a prospective pregnancy cohort, which was established between 1984 and 1987. To assemble the cohort, pregnant women of ≥26 weeks of gestation who came to the Taipei Municipal Maternal and Child Hospital in Taiwan for prenatal care were enrolled in the study and interviewed using a structured questionnaire. Detailed information, including herbal medicine use during different periods of pregnancy, was obtained during the interview. Past medical history, current obstetric data and details on conventional medicines used during pregnancy were abstracted from medical records. Data on birth weight, gestational duration and characteristics of live born infants were gathered from the Taiwan national birth register. Congenital malformation information was obtained from multiple sources: the newborn examination record (1984–7); the national death register (1984–2003); and Taiwan National Health Insurance data (1996–2000). Multiple logistic regression was used to estimate the odds ratio [OR] of major congenital malformation by herbal medicines used during the first trimester. Results: A total of 14 551 live births were analysed. After adjustment for confounding factors, taking huanglian during the first trimester of pregnancy was found to be associated with increased risk of congenital malformations of the nervous system (adjusted OR 8.62, 95% CI 2.54, 29.24). An-Tai-Yin was associated with an increased risk of congenital malformations of the musculoskeletal and connective tissues (adjusted OR 1.61, 95% CI 1.10, 2.36) and the eye (adjusted OR 7.30, 95% CI 1.47, 36.18). Conclusion: We found evidence for a possible link between the use of specific herbal medicines during the first trimester of pregnancy and increased risks of specific groups of congenital malformations. We could not investigate whether the adverse effects were related to direct toxicity from the herbal medicines, or were from misuse, contamination or uncontrolled confounding. Nonetheless, we would advise caution regarding use of herbal medicines during pregnancy, and we suggest that further investigation of these findings is warranted.

Clinical safety of inhaled corticosteroids for asthma in children: an update of long-term trials.

Abstract: Inhaled corticosteroids are established as the mainstay of maintenance therapy for chronic asthma. However, there remains some debate regarding the safety of long-term use of these agents, particularly in children. This concern mainly stems from the findings of short-term studies assessing the effects of inhaled corticosteroids on lower leg growth rate or the hypothalamic-pituitary-adrenal axis. However, the clinical relevance of these findings to long-term treatment is unknown and significant uncertainty exists regarding the predictive value of changes in cortisol levels and clinically relevant changes in growth or bone mineral density.

Valproic acid in epilepsy : pregnancy-related issues.

Abstract: Valproic acid (sodium valproate) is widely used as a first-line antiepileptic agent. As with many antiepileptic drugs, there are a number of consequences associated with the use of valproic acid in women of child-bearing potential. Most pregnancies have a favourable outcome in women with epilepsy, and these women should not be discouraged from becoming pregnant. Unlike many other antiepileptic drugs, valproic acid has no significant pharmacokinetic interactions with the steroid hormones used in oral contraceptives. During pregnancy, the major risks to mother and child result from loss of seizure control on the one hand, and an elevated risk of major congenital malformations due to antiepileptic drug treatment on the other. In particular, an elevated risk of major congenital malformations associated with valproic acid use has been a consistent finding in studies of patient registries and several large case series. In addition, developmental delay, characterised by low verbal IQ, has also been reported in children exposed to valproic acid in utero, although the relative risk is not precisely known. For these reasons, pregnancies in women being treated with valproic acid need to be planned, and the benefit-risk ratios associated with continuing valproic acid or changing treatment need to be discussed with the patient. When treatment with valproic acid is the most appropriate treatment to achieve optimal seizure control, a number of measures can be implemented to minimise risk to the fetus. These include the use of the lowest possible effective dose of valproic acid in monotherapy (ideally <1000 mg/day), appropriate folic acid supplementation and close antenatal monitoring. Regular counselling is a prerequisite for informed planning of pregnancies and optimisation of the probability of a healthy outcome. Future research on valproic acid and pregnancy should involve risk assessment in large, population-based prospective studies.

Effects Of Maternally Administered Drugs On The Fetal And Neonatal Kidney

Abstract: The number of pregnant women and women of childbearing age who are receiving drugs is increasing. A variety of drugs are prescribed for either complications of pregnancy or maternal diseases that existed prior to the pregnancy. Such drugs cross the placental barrier, enter the fetal circulation and potentially alter fetal development, particularly the development of the kidneys. Increased incidences of intrauterine growth retardation and adverse renal effects have been reported. The fetus and the newborn infant may thus experience renal failure, varying from transient oligohydramnios to severe neonatal renal insufficiency leading to death. Such adverse effects may particularly occur when fetuses are exposed to NSAIDs, ACE inhibitors and specific angiotensin II receptor type 1 antagonists. In addition to functional adverse effects, in utero exposure to drugs may affect renal structure itself and produce renal congenital abnormalities, including cystic dysplasia, tubular dysgenesis, ischaemic damage and a reduced nephron number. Experimental studies raise the question of potential long-term adverse effects, including renal dysfunction and arterial hypertension in adulthood. Although neonatal data for many drugs are reassuring, such findings stress the importance of long-term follow-up of infants exposed in utero to certain drugs that have been administered to the mother.