Introduction: The pharmacogenetic data have been studied extensively due to their clinical importance in the appropriate drug prescription. Aim: to determine allele frequencies of 27 most important ADME polymorphisms (20 of them 1A, 1B or 2A clinical annotation levels of evidence) in the Croatian population and to compare them with the European population. Materials and Methods: The 27 loci from 20 ADME genes were genotyped in the Croatian study sample consisted of 429 participants. Allele frequencies were combined with published data on the Croatian population (weighted frequencies according to sample sizes). The Croatian allele frequencies were compared with the European population average data taken from the gnomAD database (selection criteria: control cases only and non-Finnish). Results: Results showed higher variant allele frequencies in the Croatian population at six loci (rs1045642, rs2279343, rs1799853, rs1057910, rs28371725, rs9923231) and lower at two loci (rs1695, rs1801272). The most significant differences were: 0.4608 vs 0.4880 in ABCB1, 0.0932 vs 0.2430 in CYP2B6*4, 0.1228 vs 0.1470 in CYP2C9*2, 0.3325 vs 0.2980 in GSTP1 and 0.3488 vs 0.4030 in VKORC1 genes, in Europeans and Croatians respectively. Conclusions: Croatian population shows higher variant allele frequencies in several genes responsible for metabolism of anticoagulation drugs (warfarin, acenocumarol and phenprocoumon). This finding indicates higher bleeding and over- anticoagulation risk in Croatians, demanding lower drugs` prescription doses. Also, lower doses of phenytoin and celecoxib, while higher doses of digoxin, fentanyl, bupoprion and efavirenz are more frequently required in Croatians compared with European average. Acknowledgement: Croatian Science Foundation (HRZZ IP-01-2018-2497 and HRZZ-IP-2014-09- 4454).
