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Purpose: Spontaneous reporting of adverse drug reactions (ADRs) is a cornerstone in pharmacovigilance. However, information about the underlying consumption of drugs is rarely used when analysing spontaneous reports. The purpose of this study was to combine ADR reports with drug consumption data to demonstrate the additional information this gives in various scenarios, comparing different drugs, gender-stratified sub-populations and changes in reporting over time.Methods: We combined all Norwegian ADR reports in 2004-2013 from the EudraVigilance database (n = 14.028) with dispensing data from the Norwegian Prescription Database (more than 800 million dispensed prescriptions during 2004-2013). This was done in order to calculate drug-specific consumption-adjusted adverse drug reaction reporting rates (CADRRs) by dividing the number of reports for each drug with the number of users of the drug during the same time period.Results: Among the ten drugs with the highest number of ADR reports and the ten drugs with the highest CADRR, only four drugs were in both categories. This indicates that drugs with a high number of reports often also have a high number of users and that CADRR captures drugs with potentially relevant safety issues but a smaller number of users. Comparing reported ADRs in females and males using methylphenidate, we found that the two groups report different ADRs. Finally, we showed that changes in ADR reporting for simvastatin and atorvastatin during 2004-2013 were due to changes in consumption and that atorvastatin had a higher CADRR but fewer reports than simvastatin.Conclusions: CADRR provides additional information compared with number of reports alone in studies using spontaneous reports. It is important for researchers to adjust for consumption whenever possible in pharmacovigilance studies. [ABSTRACT FROM AUTHOR]

Objective: The aim of the study was to analyse non-warfarin-associated bleeding adverse drug events reported to the Norwegian spontaneous reporting system, with characterisation of the bleeding locations, outcome and drug interactions. In addition, concordance in assessments between reporters and evaluators, trend shifts in reporting, and detection of potentially new adverse drug interaction signals were studied. Methods: Data on bleeding events reported between 1 January 2003 and 31 December 2005 were retrieved from the Norwegian spontaneous reporting system database. Results: Of 327 case reports of non-warfarin-associated bleeding events, 270 reports (82.6 %) were characterised as serious and 69 (21.1 %) had a fatal outcome. One hundred and eighty-seven bleeds (57.5 %) were gastrointestinal, 57 (17.4 %) were cerebral, and 81 (24.8 %) were from other bleeding sites. The bleeding sites differed with respect to the patient's age, drug use, diagnoses and outcomes. Of drugs associated with bleeding, nonsteroidal anti-inflammatory drugs (NSAIDs)/COX-2 inhibitors (145 reports) and acetylsalicylic acid (128 reports) were most frequently used. Only fibrinolytics were associated with increased mortality. There was a 67.4 % correlation between reporters and evaluators in assessment of drugs associated with bleeding ( P < 0.001), with considerable variation in concordance between drug groups. Conclusion: Non-warfarin-associated bleeding events are associated with substantial mortality. Old age, cerebral bleeds, number of drugs used, and use of fibrinolytics are all independently associated with increased mortality. The recognition of the bleeding risk of commonly used drugs such as acetylsalicylic acid and heparins may be insufficient among prescribers. [ABSTRACT FROM AUTHOR]