Trends in Fentanyl Dispensing in Spain: The Case of Galicia (2019-2025)

In recent years, numerous countries have recorded a steady increase in opioid use. Although prescribing practices vary considerably among them, fentanyl is among the most frequently prescribed strong opioids in several European countries and in Spain. In this study, we analyzed the evolution of outpatient fentanyl dispensing in Galicia, Spain, between January 2019 and December 2025, using the Anatomical Therapeutic Chemical Classification/Defined Daily Dose (ATC/DDD) system. We paid particular attention to differences between provinces and explored temporal trends broken down by route of administration (buccal, nasal, sublingual and transdermal). Dispensing data were obtained from the General Sub-directorate of Pharmacy of the Galician Health Service (SERGAS) from the monthly billing database of official prescriptions dispensed in Galician pharmacies and were expressed as defined daily dose per 1000 inhabitants per day (DID). Dispensing rates between provinces were compared using the non-parametric Kruskal-Wallis test, considering a p-value less than 0.05 as statistically significant. We observed an increase in fentanyl use between 2019 and 2021, followed by a systematic decrease during the 2022-2025 period. Significant differences (p < 0.001) were found in the defined daily dose per 1000 inhabitants per day (DID) among the four Galician provinces, and demographic and socioeconomic factors partially explain the observed disparities. Regarding pharmaceutical presentations, transdermal patches were the most frequently used form during the study period. While some limitations should be noted, the results suggest that the observed decrease in fentanyl dispensing in Galicia could be associated with the implementation of the Ministry of Health's 2021 optimization plan, with a sustained reduction in its dispensing from 2022 onwards. However, it is necessary to maintain pharmacovigilance at the provincial level.