A patient-centred web-based adverse drug reaction reporting system identifies not yet labelled potential safety issues

PURPOSE: Reporting of adverse drug reactions (ADRs) by patients is essential for a comprehensive risk–benefit evaluation of drugs after marketing, but only few data are available regarding patient-centred web-based ADR reporting systems. Hence, we aimed to analyze ADRs reported by patients with a particular emphasis on novel drugs and serious ADRs not yet labelled in the respective summary of product characteristics (SPC). METHODS: All ADR reports received by a web-based, patient-centred platform (www.nebenwirkungen.de) between April 1, 2019, and September 1, 2020, were descriptively analyzed. ADRs and drugs were coded automatically according to MedDRA and ATC classification system. SPC labelling of reported ADRs for novel drugs marketed since 2015 was checked manually. RESULTS: In total, 13,515 patient reports including 29,529 ADRs were received during the study period (serious ADRs [SADRs] n = 1,318; 4.5%). Women were affected in more than two-thirds of ADR reports. The most common patient-reported ADRs were nausea, dizziness and headache, whereas arrhythmia, intestinal obstruction and erectile dysfunction were the most frequent SADRs. Ciprofloxacin, levothyroxine and venlafaxine were the compounds most frequently suspected for causing both ADRs and SADRs. Regarding novel compounds, 289 reports including 739 ADRs were received (mainly fatigue, headache and myalgia). Three hundred thirty-one (44.8%) out of those ADRs were not yet labelled in the respective SPC, whereof twelve were SADRs. CONCLUSION: The majority of patient-reported ADRs were non-serious. However, a relevant number of non-labelled even serious ADRs was reported for novel compounds by patients. Despite well-known limitations of patient-reported ADRs, this web-based ADR reporting system contributes to the identification of new ADRs and thus can help to improve patients’ safety complementing other pharmacovigilance instruments. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00228-021-03134-9.