Estimating environmental exposure to analgesic drugs: A cross-sectional study of drug utilization patterns in the area surrounding Sweden's largest drinking water source

•Drug utilization studies can estimate environmental impact of pharmaceuticals.•The three most-sold analgesics around Lake Mälaren were low-hazard compounds.•The majority of the sold analgesics originated from dispensed prescriptions.•The use of diclofenac is still high despite measures taken by Swedish stakeholders.•Mitigation measures should target urban areas and over-the-counter diclofenac use. Use of pharmaceuticals is continuously increasing globally and their residues are recognized as a risk for the environment. The aim of this study was to investigate drug utilization patterns of analgesics in relation to environmental hazard in the region surrounding Sweden's largest drinking water source, Lake Mälaren. This was examined using sales data on pharmaceuticals from the Swedish E-health Agency. The total sales of analgesics (non-steroidal anti-inflammatory drugs, paracetamol, other non-opioid analgesics, and opioids) for both human and veterinary use in the region were analyzed for the years 2016 to 2020, in relation to the inherent environmental hazard for each active pharmaceutical ingredient (API). We found that a total of 454 tons of analgesics were sold in the region during these 5 years. Classifications of environmental hazard were available for 16 out of the 45 studied APIs, accounting for 98.8% of the total mass in kilograms. Paracetamol, ibuprofen, and acetylsalicylic acid, which are all classified as low-hazard compounds, were the most commonly sold APIs. Diclofenac, the only pharmaceutical classified as high-hazard, was the fifth most commonly sold API, with a total sold mass of 2321 kg. The majority of the total sold mass of analgesics originated from dispensed prescriptions for human use in urban areas. Visualization of drug sales for humans and animals in different settings can be used to identify the environmental burden of pharmaceuticals. Based on our study, we suggest that additional measures to reduce the impacts of pharmaceuticals on the environment should primarily be directed to prescribing physicians in urban areas and campaigns targeted at the high over-the-counter sales of diclofenac. Moreover, it is important to address the fact that many pharmaceuticals currently have limited data on environmental hazard.