A Surveillance of Paracetamol and Nonsteroidal Anti-Inflammatory Drug Consumption in Cluj-Napoca, Romania, Using Wastewater-Based Epidemiology

Paracetamol and nonsteroidal anti-inflammatory drugs are the most popular first-line analgesics, being freely available without any medical prescription. For this reason, it is difficult to estimate their actual consumption among the population. One tool for surveillance of pharmaceutical use is wastewater-based epidemiology, a useful approach for monitoring public health by analyzing specific biomarkers in wastewater. Background/Objectives: In this study, the consumption of paracetamol and four nonsteroidal anti-inflammatory drugs (ibuprofen, naproxen, ketoprofen, and diclofenac) was evaluated by analyzing their residues as specific biomarkers in wastewater and the fraction excreted as drug metabolites in urine. Methods: For this purpose, composite wastewater samples were collected from the influent of the wastewater treatment plant in Cluj-Napoca, Romania, in four sampling campaigns (September 2021, February 2022, February 2024, and October 2024), and the target biomarkers were analyzed by liquid chromatography–tandem mass spectrometry. Results: The results of consumption expressed in g/day/1000 inhabitants showed variations for the five studied pharmaceuticals in the following ranges: 6.65–185.57 for paracetamol, 0.32–2.44 for ibuprofen, 0.29–0.82 for naproxen, 0.21–2.65 for ketoprofen, and 0.23–1.11 for diclofenac, depending on the sampling period. This variation can be explained either by the different behaviors regarding the consumption of the pharmaceutical products studied by the population during the sampling periods or by an inappropriate estimate of the number of inhabitants connected to the sewage system. Conclusions: Future studies need to establish a more comprehensive model that considers many other variables that may influence the results obtained through WBE.