Trial lecture - time and place
05.06.2026, 10.15, Helga Engs hus, Auditorium 1
The role of pharmacogenetics in modern psychiatry
Conferral summary
Dosering av antidepressive legemidler bygger ofte på konseptet om at én standarddose passer for alle, til tross for betydelig interindividuell variasjon i legemiddeleksponering mellom pasienter. Dette doktorgradsarbeidet bidrar med viktig kunnskap om hvordan farmakogenetikk og aldring påvirker metabolismen av et av de mest brukte antidepressive legemiddelene i Norge, escitalopram. Økt forståelse av hvordan metabolismen av escitalopram påvirkes av farmakogenetikk og aldring, kan muliggjøre presisjonsdosering tilpasset den enkelte pasient og dermed øke sjansen for et vellykket behandlingsutfall.
Main research findings
Escitalopram is one of the most prescribed antidepressants in Norway. The drug is mainly metabolized by the cytochrome P450 enzyme, CYP2C19, and to a lesser extent by CYP2D6 and CYP3A4. The CYP2C19 genotype is a strong determinant of escitalopram metabolism. In this thesis, three studies were conducted to further investigate how pharmacogenetics and ageing impact escitalopram metabolism. Understanding these effects can enhance dosing precision and tailoring of escitalopram treatment, thereby increasing the chance of successful outcomes.
First, CYP2D6 genotype and ageing were shown to significantly add to the CYP2C19 genotype in explaining the individual variation in escitalopram exposure. The combined CYP2C19 and CYP2D6 genotype can therefore increase precision of estimating escitalopram dose requirements for each patient in a clinical setting. Second, the metabolic ratio of the main metabolite, N-desmethyl escitalopram, to escitalopram ratio was significantly lower in individuals with absent or reduced CYP2C19 activity. The ratio may indicate the need for genotyping or even replace it when genotyping is not available. Finally, proarrhythmic changes in the human cardiac action potential were observed at therapeutic concentrations of escitalopram. The proportion of patients above threshold for arrhythmia risk was higher in patients ≥65 years than in patients <65 years, suggesting that elderly patients may have a higher risk of reaching cardiotoxic concentrations.