Utilisation of drugs with pharmacogenetic recommendations in children in Switzerland

Pharmacogenetics (PGx) is increasingly implemented in the adult population, but its potential in children remains uncertain. The aim of this study was to investigate PGx drug utilization in children in Switzerland, using Helsana claims data between 2017 and 2021. We identified 82 drugs with paediatric guideline annotations associated with variants in 24 genes from the Pharmacogenomics Knowledgebase. Of 159 172 children continuously insured, 66.1% claimed at least one PGx drug during the study period. The three PGx drugs with the highest user numbers were systemically administered ibuprofen (59.1%), ondansetron (8.3%), and locally administered fluorouracil (7.5%). Over 96% of all potential drug-gene interactions were caused by seven genes (CYP2C9, CYP2D6, DPYD, CYP2C19, MT-RNR1, CACNA1S, and RYR1). The high number of children claiming PGx drugs in Switzerland implies that a significant number of children could benefit from PGx testing.