Signal Detection in EUROmediCAT: Identification and Evaluation of Medication-Congenital Anomaly Associations and Use of VigiBase as a Complementary Source of Reference.

INTRODUCTION: Knowledge on the safety of medication use during pregnancy is often sparse. Pregnant women are generally excluded from clinical trials, and there is a dependence on post-marketing surveillance to identify teratogenic medications. AIMS: This study aimed to identify signals of potentially teratogenic medications using EUROmediCAT registry data on medication exposure in pregnancies with a congenital anomaly, and to investigate the use of VigiBase reports of adverse events of medications in the evaluation of these signals. METHODS: Signals of medication-congenital anomaly associations were identified in EUROmediCAT (21,636 congenital anomaly cases with 32,619 medication exposures), then investigated in a subset of VigiBase (45,749 cases and 165,121 exposures), by reviewing statistical reporting patterns and VigiBase case reports. Evidence from the literature and quantitative and qualitative aspects of both datasets were considered before recommending signals as warranting further independent investigation. RESULTS: EUROmediCAT analysis identified 49 signals of medication-congenital anomaly associations. Incorporating investigation in VigiBase and the literature, these were categorised as follows: four non-specific medications; 11 likely due to maternal disease; 11 well-established teratogens; two reviewed in previous EUROmediCAT studies with limited additional evidence; and 13 with insufficient basis for recommending follow-up. Independent investigations are recommended for eight signals: pregnen (4) derivatives with limb reduction; nitrofuran derivatives with cleft palate and patent ductus arteriosus; salicylic acid and derivatives with atresia or stenosis of other parts of the small intestine and tetralogy of Fallot; carbamazepine with atrioventricular septal defect and severe congenital heart defect; and selective beta-2-adrenoreceptor agonists with posterior urethral valve and/or prune belly. CONCLUSION: EUROmediCAT data should continue to be used for signal detection, accompanied by information from VigiBase and review of the existing literature to prioritise signals for further independent evaluation.

Studying the Evolving Knowledge of Adverse Drug Reactions in Order to Facilitate the Rational Use of Medicines in Paediatric Patients.

Pharmacovigilance, which is the science and activities relating to the detection, assessment, understanding and prevention of adverse effects or any other possible drug-related problems, generates knowledge to facilitate the rational use of medicines. When a medicine is first marketed, there is limited information on adverse drug reactions (ADRs), especially in paediatrics, where medicines are less likely to have been extensively studied. Knowledge in drug safety is built up over time when more (in number, and more heterogeneous) patients are treated than were studied in the randomised controlled trials preceding the marketing of a medicine. Previously not recognised ADRs are often initially described in case reports and case series. Prospective cohort studies are useful in determining the incidence and risk factors of common ADRs. Case series and pharmacovigilance reporting systems have been useful in identifying previously unknown uncommon ADRs and risk factors for specific ADRs. This brief review provides examples that illustrate how various study designs and data sources contribute to the evolving knowledge of ADRs that is essential to help develop guidelines and improve the rational use of medicines.

Paediatric safety signals identified in VigiBase: Methods and results from Uppsala Monitoring Centre.

PURPOSE: The purpose of this study is to uncover previously unrecognised risks of medicines in paediatric pharmacovigilance reports and thereby advance a safer use of medicines in paediatrics. METHODS: Individual case safety reports (ICSRs) with ages less than 18 years were retrieved from VigiBase, the World Health Organization (WHO) global database of ICSRs, in September 2014. The reports were grouped according to the following age spans: 0 to 27 days; 28 days to 23 months; 2 to 11 years; and 12 to 17 years. vigiRank, a data-driven predictive model for emerging safety signals, was used to prioritise the list of drug events by age groups. The list was manually assessed, and potential signals were identified to undergo in-depth assessment to determine whether a signal should be communicated. RESULTS: A total of 472 drug-event pairs by paediatric age groups were the subject of an initial manual assessment. Twenty-seven drug events from the two older age groups were classified as potential signals. An in-depth assessment resulted in eight signals, of which one concerned harm in connection with off-label use of dextromethorphan and another with accidental overdose of olanzapine by young children, and the remaining signals referred to potentially new causal associations for atomoxetine (two signals), temozolamide, deferasirox, levetiracetam, and desloratadine that could be relevant also for adults. CONCLUSIONS: Clinically relevant signals were uncovered in VigiBase by using vigiRank applied to paediatric age groups. Further refinement of the methodology is needed to identify signals in reports with ages under 2 years and to capture signals specific to the paediatric population as a risk group.

Pharmacovigilance in pediatrics.

The characteristics of pharmacology and drug evaluation in the pediatric age group highlight the necessity for the pharmacovigilance community to adjust to the specific features of children. At the time of marketing a medicinal product intended for children, the product's safety profile is sometimes less well known than for adults due to fewer or small sample clinical trials. Furthermore, the frequent off-labeled drug use, the use of unsuitable dosage forms and the need for continuous dose adjustments increase the risk of medication errors and thus lead to avoidable adverse drug reactions (ADRs). The occurrence of child-specific ADRs (such as growth disorders) or ADRs more commonly occurring in children than in adults make it necessary to monitor the safety of child-specific drugs. Pediatric pharmacovigilance includes also the consequences of in utero exposure, whether manifestations are present from birth or occur in early childhood (such as neurodevelopmental disorders). The incidence of ADRs varies with age, setting of medical care (in- or out-patients, pediatric specialties) and by country in which the study was carried out. The drugs most frequently reported with ADRs are those most commonly used in the pediatric age group, i.e. antibiotics and vaccines. The ADRs most often reported are skin, neurological and general disorders. As in adults, spontaneous notification is essential to generate alerts and child-specific pharmacoepidemiological studies are necessary and should be developed.

Safety Concerns Reported by Patients Identified in a Collaborative Signal Detection Workshop using VigiBase: Results and Reflections from Lareb and Uppsala Monitoring Centre.

INTRODUCTION: Patient reporting in pharmacovigilance is important and contributes to signal detection. However, descriptions of methodologies for using patient reports in signal detection are scarce, and published experiences of how patient reports are used in pharmacovigilance are limited to a few individual countries. OBJECTIVE: Our objective was to explore the contribution of patient reports to global signal detection in VigiBase. METHODS: Data were retrieved from VigiBase in September 2016. Drug-event-combination series were restricted to those with >50% patient reports, defined as reporter type "Consumer/non-health professional" per E2B reporting standard. vigiRank was applied to patient reports to prioritize combinations for assessment. Product information for healthcare professionals (HCPs) as well as patient information leaflets (PILs) were used as reference for information on adverse drug reactions (ADRs). Staff from the Uppsala Monitoring Centre and the Netherlands Pharmacovigilance Centre Lareb categorized the combinations. Potential signals proceeded to a more in-depth clinical review to determine whether the safety concern should be communicated as a "signal." RESULTS: Of the 212 combinations assessed, 20 (9%) resulted in eight signals communicated within the World Health Organization (WHO) programme for international drug monitoring. Review of PILs revealed insufficient ADR descriptions for patients and examples of poor consistency with product information for HCPs. Patient narratives provided details regarding the experience and impact of ADRs and evidence that patients make causality and personal risk assessments. CONCLUSIONS: Safety concerns described in patient reports can be identified in a global database including previously unknown ADRs as well as new aspects of known ADRs. Patient reports provide unique information valuable in signal assessment and should be included in signal detection. Novel approaches to highlighting patient reports in statistical signal detection can further improve the contribution of patient reports to pharmacovigilance.

A method for data-driven exploration to pinpoint key features in medical data and facilitate expert review.

PURPOSE: To develop a method for data-driven exploration in pharmacovigilance and illustrate its use by identifying the key features of individual case safety reports related to medication errors. METHODS: We propose vigiPoint, a method that contrasts the relative frequency of covariate values in a data subset of interest to those within one or more comparators, utilizing odds ratios with adaptive statistical shrinkage. Nested analyses identify higher order patterns, and permutation analysis is employed to protect against chance findings. For illustration, a total of 164 000 adverse event reports related to medication errors were characterized and contrasted to the other 7 833 000 reports in VigiBase, the WHO global database of individual case safety reports, as of May 2013. The initial scope included 2000 features, such as patient age groups, reporter qualifications, and countries of origin. RESULTS: vigiPoint highlighted 109 key features of medication error reports. The most prominent were that the vast majority of medication error reports were from the United States (89% compared with 49% for other reports in VigiBase); that the majority of reports were sent by consumers (53% vs 17% for other reports); that pharmacists (12% vs 5.3%) and lawyers (2.9% vs 1.5%) were overrepresented; and that there were more medication error reports than expected for patients aged 2-11 years (10% vs 5.7%), particularly in Germany (16%). CONCLUSIONS: vigiPoint effectively identified key features of medication error reports in VigiBase. More generally, it reduces lead times for analysis and ensures reproducibility and transparency. An important next step is to evaluate its use in other data.

Retrospective review of paediatric case reports of Stevens-Johnson syndrome and toxic epidermal necrolysis with lamotrigine from an international pharmacovigilance database.

OBJECTIVES: This study aims to characterise paediatric reports with lamotrigine (LTG) and Stevens-Johnson syndrome or toxic epidermal necrolysis (SJS/TEN), and to explore whether potential risk factors can be identified. DESIGN: This is a retrospective review of suspected adverse drug reaction (ADR) reports. Reported time from LTG start to SJS/TEN onset, indication for use and dose was explored. To identify potential risk groups, report features (eg, ages, patient sex, co-reported drugs) for LTG and SJS/TEN were contrasted with two reference groups in the same database, using shrinkage logOR. SETTING: Reports were retrieved from VigiBase, the WHO global database of individual case safety reports, in January 2015. PATIENTS: Data for patients aged ≤17 years old were extracted. RESULTS: There were 486 reports of SJS/TEN in LTG-treated paediatric patients. Ninety-seven per cent of the cases with complete information on time to onset of SJS/TEN occurred within 8 weeks of initiation of LTG therapy. The median time to onset was 15 days (IQR: 10-22 days). The proportion of SJS/TEN with LTG and valproic acid (VPA) co-reporting was significantly more than non-cutaneous ADRs (43% vs 19%, (logOR: 1.60 (99% CI: 1.33 to 1.84)). CONCLUSIONS: The results suggest that VPA co-medication with LTG therapy is a risk factor for SJS/TEN in the paediatric population. Although this relationship has been identified from individual case reports, this is the first supportive study from a large compilation of cases. SJS/TEN risk is highest in first 8 weeks of treatment with LTG in children and clinicians should be aware of this risk during this period.

Adverse drug reactions in Nigerian children: a retrospective review of reports submitted to the Nigerian Pharmacovigilance Centre from 2005 to 2012.

BACKGROUND: Adverse drug reactions (ADRs) in children recorded in national pharmacovigilance databases in high-income countries have been analysed. Nigeria has a population of 31 million children and became a member of the WHO Programme for International Drug Monitoring in 2004 since when it has been submitting reports of suspected ADRs to the WHO Global Individual Case Safety Report database, VigiBase. OBJECTIVE: To gain information on reported ADRs in Nigerian children aged 0-17 years in VigiBase from 2005 to 2012. METHODS: The data were analysed for annual reports, age and sex of patients, type of reporters, suspected drugs and adverse reactions. The most commonly reported ADRs and suspected drugs were ranked, and drugs associated with the fatalities were evaluated. RESULTS: A total of 297 reports of 473 ADRs in 297 children were received from doctors, pharmacists, other health-care professionals and consumers during the period. ADRs were most frequently reported for anti-retrovirals (74, 24%), antibiotics (71, 23%) and anti-malarials (60, 20%). The most frequently reported ADRs were rash (15.2%), fever (10.3%) and pruritus (6.8%). Anti-infective agents were responsible for more than half of the reports. Twenty-one children (7%) died, eight from acute renal failure. Seven of the cases of acute renal failure were associated with contaminated paracetamol/diphenhydramine hydrochloride and herbal medicines used for teething problems. In the majority of cases, the products were contaminated with diethylene glycol. There were 14 cases of Stevens-Johnson syndrome, three of which were fatal. CONCLUSION: Anti-infective agents (antibiotics, anti-malarials and anti-retrovirals) were associated with a majority of the ADRs. Stevens-Johnson syndrome was the most frequent severe ADR. Some of the fatalities were associated with sub-standard and herbal medications.

Adverse drug reaction reports for cardiometabolic drugs from sub-Saharan Africa: a study in VigiBase.

OBJECTIVE: Identifying key features in individual case safety reports (ICSR) of suspected adverse drug reactions (ADRs) with cardiometabolic drugs from sub-Saharan Africa (SSA) compared with reports from the rest of the world (RoW). METHODS: Reports on suspected ADRs of cardiometabolic drugs (ATC: A10[antidiabetic], B01[antithrombotics] and C[cardiovascular]) were extracted from WHO Global database, VigiBase(®) (1992-2013). We used vigiPoint, a logarithmic odds ratios (log2 OR)-based method to study disproportional reporting between SSA and RoW. Case-defining features were considered relevant if the lower limit of the 99% CI > 0.5. RESULTS: In SSA, 3773 (9%) of reported ADRs were for cardiometabolic drugs, in RoW for 18%. Of these, 79% originated from South Africa and 81% were received after 2007. Most reports were for drugs acting on the renin-angiotensin system (36% SSA & 14% RoW). Compared with RoW, reports were more often sent for patients 18-44 years old (log2 OR 0.95 [99 CI 0.80; 1.09]) or with non-fatal outcome (log2 OR 1.16 [99 CI 1.10; 1.22]). Eight ADRs (cough, angioedema, lip swelling, face oedema, swollen tongue, throat irritation, drug ineffective and blood glucose abnormal) and seven drugs (enalapril, rosuvastatin, perindopril, vildagliptin, insulin glulisine, nifedipine and insulin lispro) were disproportionally more reported in SSA than in the RoW. CONCLUSIONS: 'In recent years, the number of adverse drug reactions (ADRs) reported in Sub-Saharan Africa (SSA) has sharply increased. The data showed the well-known population-based differential ADR profile of ACE inhibitors in the SSA population.'

Longitudinal medical records as a complement to routine drug safety signal analysis.

PURPOSE: To explore whether and how longitudinal medical records could be used as a source of reference in the early phases of signal detection and analysis of novel adverse drug reactions (ADRs) in a global pharmacovigilance database. METHODS: Drug and ADR combinations from the routine signal detection process of VigiBase® in 2011 were matched to combinations in The Health Improvement Network (THIN). The number and type of drugs and ADRs from the data sets were investigated. For unlabelled combinations, graphical display of longitudinal event patterns (chronographs) in THIN was inspected to determine if the pattern supported the VigiBase combination. RESULTS: Of 458 combinations in the VigiBase data set, 190 matched to corresponding combinations in THIN (after excluding drugs with less than 100 prescriptions in THIN). Eighteen percent of the VigiBase and 9% of the matched THIN combinations referred to new drugs reported with serious reactions. Of the 112 unlabelled combinations matched to THIN, 52 chronographs were inconclusive mainly because of lack of data; 34 lacked any outstanding pattern around the time of prescription; 24 had an elevation of events in the pre-prescription period, hence weakened the suspicion of a drug relationship; two had an elevated pattern of events exclusively in the post-prescription period that, after review of individual patient histories, did not support an association. CONCLUSIONS: Longitudinal medical records were useful in understanding the clinical context around a drug and suspected ADR combination and the probability of a causal relationship. A drawback was the paucity of data for newly marketed drugs with serious reactions.

Valproic acid and fatalities in children: a review of individual case safety reports in VigiBase.

INTRODUCTION: Valproic acid is an effective first line drug for the treatment of epilepsy. Hepatotoxicity is a rare and potentially fatal adverse reaction for this medicine. OBJECTIVE: Firstly to characterise valproic acid reports on children with fatal outcome and secondly to determine reporting over time of hepatotoxicity with fatal outcome. METHODS: Individual case safety reports (ICSRs) for children ≤ 17 years with valproic acid and fatal outcome were retrieved from the WHO Global ICSR database, VigiBase, in June 2013. Reports were classified into hepatotoxic reactions or other reactions. Shrinkage observed-to-expected ratios were used to explore the relative reporting trend over time and for patient age. The frequency of polytherapy, i.e. reports with more than one antiepileptic medicine, was investigated. RESULTS: There have been 268 ICSRs with valproic acid and fatal outcome in children, reported from 25 countries since 1977. A total of 156 fatalities were reported with hepatotoxicity, which has been continuously and disproportionally reported over time. There were 31 fatalities with pancreatitis. Other frequently reported events were coma/encephalopathy, seizures, respiratory disorders and coagulopathy. Hepatotoxicity was disproportionally and most commonly reported in children aged 6 years and under (104/156 reports) but affected children of all ages. Polytherapy was significantly more frequently reported for valproic acid with fatal outcome (58%) compared with non-fatal outcome (34%). CONCLUSION: Hepatotoxicity remains a considerable problem. The risk appears to be greatest in young children (6 years and below) but can occur at any age. Polytherapy is commonly reported and seems to be a risk factor for hepatotoxicity, pancreatitis and other serious adverse drug reactions with valproic acid.

Pharmacovigilance for children's sake.

Child age-specific information on efficacy and risk of medicines can be limited for healthcare professionals and patients. It is therefore very important to make the best use of a risk planned approach to the pharmacological treatment of children. This means pharmacovigilance in the broadest sense of gaining the best data from the use of medicines in clinical practice. We consider issues that complicate safe medication use in paediatric care, as well as current progress and provide suggestions for building knowledge within paediatric pharmacovigilance to be used to minimise patient harm. The continuous development in children constitutes a challenge to prescribing and administering age-suitable doses for individual children. Children are not only different from adults but differ vastly within their own age group. Physical growth during childhood is apparent to the eye, but less obvious is the ongoing maturation of organ function important for drug disposition and action. Systematic issues such as medication errors, off-label use and the lack of age-suitable formulations are considerable obstacles for safe medication use in paediatrics. The recognition of emerging adverse drug reactions could be more challenging in developing children. Initiatives to improve the situation have been made by the WHO and regulators in the USA and EU. Age-specific changes in physiology, pharmacology and psychology, as well as systematic issues specific for children need to be considered in the work of assessing spontaneous reports in children. Pharmacovigilance needs to broaden its aims considerably beyond merely capturing new associations between drugs and events, and encompass careful collection on patient characteristics and circumstances around the reported adverse drug reaction to provide essential information that will give clues on how to prevent harm to children.

Outlier removal to uncover patterns in adverse drug reaction surveillance - a simple unmasking strategy.

PURPOSE: This study aimed to develop an algorithm for uncovering associations masked by extreme reporting rates, characterize the occurrence of masking by influential outliers in two spontaneous reporting databases and evaluate the impact of outlier removal on disproportionality analysis. METHODS: We propose an algorithm that identifies influential outliers and carries out parallel analysis after their omission. It considers masking of drugs as well as of adverse drug reactions (ADRs), uses a direct measure of the masking effect and makes no assumptions regarding the number of outliers per drug or ADR. The occurrence of masking is characterized in the WHO Global Individual Case Safety Report database, VigiBase and a regional collection of reports from Shanghai, China. RESULTS: For WHO-ART critical terms such as myocardial infarction, rhabdomyolysis and hypoglycaemia outlier removal led to a 25-50% increase in the number of Statistics of Disproportionate Reporting (SDR) and gains in time to detection of 1-2 years, while keeping the rate of spurious SDRs from the parallel analysis at 1%. Twenty-three per cent of VigiBase and 18% of Shanghai SRS reports listed an influential outlier. Twenty-seven per cent of the ADRs and 5% of the drugs in VigiBase, and 2% of the ADRs and 3% of the drugs in Shanghai SRS were involved in an outlier. The overall increase in the number of SDRs for both datasets was 3%. CONCLUSION: Masking by outliers has substantial impact on specific ADRs including, in VigiBase, rhabdomyolysis, myocardial infarction and hypoglycaemia. It is a local phenomenon involving a fair number of reports but yielding a limited number of additional SDRs.

The impact of duration of treatment on reported time-to-onset in spontaneous reporting systems for pharmacovigilance.

Within pharmacovigilance, knowledge of time-to-onset (time from start of drug administration to onset of reaction) is important in causality assessment of drugs and suspected adverse drug reactions (ADRs) and may indicate pharmacological mechanisms involved. It has been suggested that time-to-onset from individual case reports can be used for detection of safety signals. However, some ADRs only occur during treatment, while those that do occur later are less likely to be reported. The aim of this study was to investigate the impact of treatment duration on the reported time-to-onset. Case reports from the WHO Global ICSR database, VigiBase, up until February 5(th) 2010 were the basis of this study. To examine the effect of duration of treatment on reported time-to-onset, angioedema and hepatitis were selected to represent short and long latency ADRs, respectively. The reported time-to-onset for each of these ADRs was contrasted for a set of drugs expected to be used short- or long-term, respectively. The study included 2,980 unique reports for angioedema and 1,159 for hepatitis. Median reported time-to-onset for angioedema in short-term treatments ranged 0-1 days (median 0.5), for angioedema in long-term treatments 0-26 days (median 8), for hepatitis in short-term treatments 4-12 days (median 7.5) and for hepatitis in long term treatments 19-73 days (median 28). Short-term treatments presented significantly shorter reported time-to-onset than long-term treatments. Of note is that reported time-to-onset for angioedema for long-term treatments (median value of medians being 8 days) was very similar to that of hepatitis for short-term treatments (median value of medians equal 7.5 days). The expected duration of treatment needs to be considered in the interpretation of reported time-to-onset and should be accounted for in signal detection method development and case evaluation.

Challenges of safe medication practice in paediatric care--a nursing perspective.

AIM: To explore nurses' experiences of handling medications in paediatric clinical practice, with a focus on factors that hinder and facilitate safe medication practices. METHODS: Twenty nurses (registered nurses) from four paediatric wards at two hospitals in Sweden were interviewed in focus groups. The interviews were analysed using content analysis. RESULTS: Six themes emerged from the analysed interviews: the complexity specific for nurses working on paediatric wards is a hindrance to safe medication practices; nurses' concerns about medication errors cause a considerable psychological burden; the individual nurse works hard for safe medication practices and values support from other nurse colleagues; circumstances out of the ordinary are perceived as critical challenges for maintaining patient safety; nurses value clear instructions, guidelines and routines, but these are often missing, variable or changeable; management, other medical professionals, the pharmacy, the pharmaceutical industry and informatics support need to respond to the requirements of the nurses' working situations to improve safe medication practices. CONCLUSION: Weaknesses were apparent in the long chain of the medication-delivery process. A joint effort by different professions involved in that delivery process, and a nationwide collaboration between hospitals is recommended to increase safe medication practices in paediatric care.

Rhabdomyolysis reported for children and adolescents treated with antipsychotic medicines: a case series analysis.

OBJECTIVE: Rhabdomyolysis is a rare and potentially serious adverse drug reaction (ADR) to antipsychotic medicines. The aim of this study was to investigate the clinical circumstances surrounding the diagnosis of rhabdomyolysis in children and adolescents treated with antipsychotic medicines. We also critically reviewed individual case safety reports (ICSRs) of suspected ADRs to evaluate how clinically useful they can be in a case series analysis. METHODS: This was a descriptive and an exploratory study. Published case reports and ICSRs from the World Health Organization (WHO) Global ICSR database, VigiBase, reported with rhabdomyolysis and antipsychotic medicines for patients ≤17 years years of age were described. Reporting patterns of ICSRs with rhabdomyolysis and antipsychotic medicines were explored in VigiBase for children and adolescents and for adults. The VigiBase ICSRs were also systematically evaluated regarding the report content. RESULTS: Of the 26 evaluated reports, 6 co-reported neuroleptic malignant syndrome (NMS) and 20 reports concerned rhabdomyolysis in the absence of NMS. The reported suspected antipsychotic medicines for these 20 reports were olanzapine, risperidone, haloperidol, paliperidone, quetiapine, clozapine, cyamemazine, and aripiprazole. In VigiBase, rhabdomyolysis (in the absence of NMS) was reported more frequently with olanzapine relative to all reports for children and adolescents with antipsychotic medicines. In the range of events that preceded rhabdomyolysis, muscle pains and abdominal pain were commonly recorded to have started during the week prior to the diagnosis. Other preceding symptoms were general weakness and dark urine. Onset of rhabdomyolysis for most patients occurred at any time within 2 months of starting antipsychotic treatment, in several cases triggered by changes to the patient's drug therapy or known risk factors of rhabdomyolysis. It was found that ICSRs can contribute with additional information, but that access to free text and narratives were crucial in order to capture clinically useful features of rhabdomyolysis. CONCLUSION: Monitoring of children and adolescents needs to be intensified during dose increases, or when a new, added, or switched antipsychotic medicine is introduced to their drug regimen, and during exposure to known risk factors for rhabdomyolysis. The development of seemingly nonserious events, such as abdominal pain, muscle pain, weakness, and dark urine, should be followed up during antipsychotic use, as they might be precursory events to rhabdomyolysis that eventually could develop into acute renal failure.

Severe muscle symptoms with lipid-lowering agents may be confused with neurogenic claudication associated with spinal canal stenosis.

BACKGROUND: Screening of the WHO global individual case safety report database (VigiBase) has recently identified case reports with HMG CoA reductase inhibitors and muscle symptoms co-reported with spinal stenosis. In some reports spinal stenosis appears to have been listed as a coincidental finding. OBJECTIVE: To assess reports with sufficient information to ascertain if they suggested that there may have been diagnostic confusion between muscle symptoms attributable to HMG CoA reductase inhibitors with or without ezetimibe and symptoms of spinal stenosis. METHOD: Reports were examined for patient demographics, past history, clinical and investigational findings, co-prescribed medicines and outcomes. RESULTS: Three case histories recorded details suggestive of diagnostic confusion between severe and disabling muscle symptoms affecting the lower limbs attributable to an HMG CoA reductase inhibitor with and without ezetimbe and symptoms of neurogenic claudication due to spinal stenosis. The statins were not discontinued promptly leading to prolonged morbidity. Serum creatine kinase levels (CK) were normal in two patients and not recorded for the third. CONCLUSION: The reports include two safety issues, firstly the need to consider HMG CoA reductase inhibitors as a cause of severe lower limb muscle symptoms even in the presence of spinal stenosis and normal CK levels and the second, the need to measure serum creatine kinase when these symptoms occur to detect progression of myopathy and potentially serious outcomes.