Antidepressant drug switching in the Swiss population with a focus on Escitalopram and drugs with pharmacogenetic dosing guidelines: a drug utilization study using claims data

Depression affects around 10% of the Swiss population. While SSRIs are commonly prescribed, only 30-40% of patients achieve remission. Pharmacogenetic (PGx) factors may explain part of this high rate of SSRI treatment failure. This study examined antidepressant (AD) switching among Swiss patients using escitalopram, focusing on whether they switched to ADs with PGx dosing guidelines (PGx AD) or ADs without PGx dosing guidelines (non-PGx ADs). Data from Swiss health insurance records identified 41 275 patients who used escitalopram between July 2020 and June 2022. While 6.4% (n = 2 638) switched to another antidepressant, only 35.4% of these opted for a PGx AD. Men, younger adults showed higher switching rates, whereas patients on antipsychotic medications switched less. Individuals younger than 20 years old and women were more likely to switch to PGx AD whereas the elderly were less likely to switch to PGx AD.