A team of researchers in Ireland have conducted a prospective observational pilot study to assess the prevalence, severity and preventability of adverse drug reactions (ADRs), ADRs causing or contributing to hospitalisation (cADRs) and preventable ADRs (pADRs) in middle-aged adults aged 45-64 years. 23 ADRs were identified in 21 of the 100 patients included in the study, with the prevalence of cADRs and pADRs being 14% and 11%, respectively. 14 ADRs required hospitalisation for urgent medical review, while potentially inappropriate prescribing was linked with the occurrence of any ADR (adjusted odds ratio 3.49; 95% confidence interval 1.22–9.93). Excessive polypharmacy (ten or more medicines) was linked to occurrence of any ADR (χ2 = 5.73, p = 0.02), but polypharmacy (five or more medicines) was not. The researchers conclude that one in five patients in the study experienced an ADR, preventable in 11 cases. These findings demonstrate the susceptibility of middle-aged patients to medicine-related harm, although additional research is required to comprehensively describe the prevalence, severity and preventability of ADRs in this population. The full study can be viewed here