Background/Aim: Adverse drug reactions (ADRs) represent a major concern leading to significant increases in both morbidity and mortality globally. Providing healthcare professionals (HCPs) and patients with real-world data on drug safety is imperative to facilitate informed decisionmaking. The study aimed to determine the feasibility of creating comparative safety charts for medicines by mapping ADR reporting onto prescribing data. Materials and Methods: Data on serious and fatal ADR reports from the Yellow Card database was mapped onto general practice prescription data in England. The rate of serious and fatal ADR reports per million items prescribed was calculated for commonlyprescribed medicines. Results: Quantitative comparative analyses for 137 medicines belonging to 26 therapeutic classes were conducted. Significant differences were observed within most therapeutic classes for the rate of serious and fatal ADR reports per prescribing unit. Conclusion: Despite the limitations of ADR reporting and prescribing databases, the study provides a proof-of-concept for the feasibility of mapping ADR reporting onto prescribing data to create comparative safety charts that could support evidence-based decision-making around formulary choices.All medicines can cause adverse drug reactions (ADRs) leading to increases in both mortality and morbidity and incurring substantial financial costs and a significant burden on healthcare systems worldwide (1-8). The reported prevalence of ADRs in primary care is 8.3%, one fifth of which are preventable (9). Serious ADRs may be life-threatening, resulting in death or hospitalisation and may cause permanent disability or congenital abnormalities (birth defects) (10). These serious ADRs account for up to 30% of all ADRs with many being identified post-marketing (11-13). It has been shown that 30-70% of ADRs resulting in hospitalisation are considered predictable and thereby potentially preventable (11,(14)(15)(16)(17).The detection and quantification of ADRs is a key component of clinical trials prior to approval. While clinical trials are considered the bedrock for assessing drug efficacy, they are less efficient in detecting ADRs, therefore, findings from clinical trials have limited use in extrapolating risks to clinical practice (18-25). Unlike easily-detectable and wellrecognised ADRs that are often identified during pre-marketing in clinical trials, rare and late-onset ADRs remain underdetected until the post-marketing stage, during which medicines are used by a more diverse and larger population than initially intended, and for a longer period in normal clinical practice (26)(27)(28)(29)(30). Such ADRs are often undetected during clinical trials due to the relatively small number of participants studied (30-33) and the exclusion criteria, which do not usually allow for the frailest patients to participate (34). The limited trial duration and the focus on main outcomes can also hamper the detection of unpredictable (35-37) and relatively-infrequent events (38) that are rare...