The Canadian Emergency Team Initiative (CETI) cohort showed that minor injuries like sprained ankles or small fractures trigger a downward spiral of functional decline in 16% of independent seniors up to 6months post-injury. Such seniors frequently receive medications with sedative or anticholinergic properties. The Drug Burden Index (DBI), which summarises the drug burden of these specific medications, has been associated with decreased physical and cognitive functioning in previous research. We aimed to assess the contribution of the DBI to functional decline in the CETI cohort. CETI participants were assessed physically and cognitively at baseline during their consultations at emergency departments (EDs) for their injuries and up to 6months thereafter. The medication data were used to calculate baseline DBI and functional status was measured with the Older Americans Resources and Services (OARS) scale. Multivariate linear regression models assessed the association between baseline DBI and functional status at 6months, adjusting for age, sex, baseline OARS, frailty level, comorbidity count, and mild cognitive impairment. The mean age of the 846 participants was 77years and their mean DBI at baseline was 0.24. Complete follow-up data at 3 or 6months was available for 718 participants among whom a higher DBI at the time of injury contributed to a lower functional status at 6months. Each additional point in the DBI lead to a loss of 0.5 points on the OARS functional scale, p < 0.001. Among those with a DBI ≥ 1, 27.4% were considered 'patients who decline' at 3 or 6months' follow-up, compared with 16.0% of those with a DBI of 0 (p = 0.06). ED visits are considered missed opportunities for optimal care interventions in seniors; Identifying their DBI and adjusting treatment accordingly may help limit functional decline in those at risk after minor injury.