OBJECTIVES: Metformin is widely used medicine for several indications. The aim of this research was to analyse metformin consumption in Republic of Serbia and Croatia 2006 - 2020, and additionally in Montenegro 2016 - 2020 (data available for this period), since new publications showed its presence in wastewater world-wide.

METHODS: Screening of publicly available sources of respective Health Authotities, in Serbia and Croatia agencies for medicines and medical devices (ALIMS, HALMED), and in Montenegro Institute for medicines and medical devices (CInMED), with cut-off date June 15th, 2022. Based on available data, using World Health Organization DDD per 1000 inhabitants per day methodology, database was created and analyzed.

RESULTS: Consumption of metformin in Serbia has increased 3.97 times from 2006 until 2020, with DDD per 1000 inhabitants per day value 10.71 vs 42.45. In Croatia, for the same period, consumption increased 2.7 times (9.02 vs 24.35). In Montenegro, increase in consumption in 5 year period is also noticed, from 21.70 in 2016, to 28.54 in 2020 (1.32 times growth). Comparison between countries showed that in 2006, consumption in Serbia and Croatia was comparable, in 2010 in Serbia consumption was 1.39 times higher (19.08 vs 13.72), and this trend continued in 2015 with 1.6 times higher consumption (33.30 vs 20.86), and also in 2020 where consumption in Serbia was 1.75 times higher compared to Croatia. In 2016, consumption in Croatia and Montenegro was comparable (22.08 vs 21.70) while in Serbia it was higher (34.77). In all three countries metformin was in top 15 consumed medicines (INN) since 2016.

CONCLUSIONS: Metformin consumption in three selected countries showed continuous growth, with highest consumption in Serbia in all 15 years. Further research is needed which would show what are the causes of this increase in metformin consumption in these European countries.