Adverse drug reactions are a relevant cause of emergency department visits, accounting for 6.5% of the total visits in this study, and often lead to hospital admission. The ADRED (Adverse Drug Reactions in Emergency Departments) study, which is now being conducted, is intended to shed further light on their causes, patient risk factors, and potential avoidability.

No abstract

IntroductionDrug–drug interactions (DDIs) are an important risk factor for adverse drug reactions. Older, polymedicated patients are particularly affected. Although antithrombotics have been detected as high-risk drugs for DDIs, data on older patients exposed to them are scarce.MethodsBaseline data of 365 IDrug study outpatients (≥ 60 years, use of an antithrombotic and one or more additional long-term drug) were analyzed regarding potential drug–drug interactions (pDDIs) with a clinical decision support system. Data included prescription and self-medication drugs.ResultsThe prevalence of having one or more pDDI was 85.2%. The median number of alerts per patient was three (range 0–17). For 58.4% of the patients, potential severe/contraindicated interactions were detected. Antiplatelets and non-steroidal anti-inflammatory drugs (NSAIDs) showed the highest number of average pDDI alert involvements per use (2.9 and 2.2, respectively). For NSAIDs, also the highest average number of severe/contraindicated alert involvements per use (1.2) was observed. 91.8% of all pDDI involvements concerned the 25 most frequently used drug classes. 97.5% of the severe/contraindicated pDDIs were attributed to only nine different potential clinical manifestations. The most common management recommendation for severe/contraindicated pDDIs was to intensify monitoring. Number of drugs was the only detected factor significantly associated with increased number of pDDIs (p < 0.001).ConclusionThe findings indicate a high risk for pDDIs in older, polymedicated patients on antithrombotics. As a consequence of patients’ frequently similar drug regimens, the variety of potential clinical manifestations was small. Awareness of these pDDI symptoms and the triggering drugs as well as patients’ self-medication use may contribute to increased patient safety.

Older patients in particular suffer from adverse drug reactions (ADR) when presenting in the emergency department. We aimed to characterise the phenotype of those ADRs, to be able to recognise an ADR in older patients. Methods: Cases of ADRs in emergency departments collected within the multicentre prospective observational study (ADRED) were analysed (n = 2215). We analysed ADR-associated diagnoses, symptoms and their risk profiles. We present frequencies and odds ratios (OR) with 95% confidence intervals for adults (18-64 years) compared to older adults (≥65 years; young-old 65-79, old-old ≥80 years) and regression coefficients (B) for each year of age. Results: Most prominent differences were seen for drug-associated confusion, dehydration, and bradycardia (OR 6.70 [1.59-28.27], B .054; OR 6.02 [2.41-15.03], B .081, and 4.82 [2.21-10.54], B .040), more likely seen in older adults. Bleedings were reported in all age groups, but gastrointestinal bleedings occurred with more than doubled chance in older adults (OR 2.46 [1.77-3.41], B .030), likewise did other bleedings such as haemorrhage from respiratory passages (OR 2.89 [1.37-6.11], B.036). Falls were more likely in older adults (OR 2.84 [1.77-4.53], B .030), while dizziness was frequent in both age groups. Conclusion: Our data point to differences in symptoms of ADRs between adults and older individuals, with dangerous drug-associated phenomena in the older adult such as bleedings or falls. Physicians should consider drug-associated origins of symptoms in older adults with an increased risk for serious health problems.