634. Implementation of Pharmacogenetics in Psychiatry across the world: the European Continent

Abstract

Abstract Background Pharmacogenetics (PGx) is a discipline that investigates heritable genetic variation that impacts drug absorption, metabolization and transport of drugs thereby affecting therapy outcome (van Westrhenen et al. Frontiers in Pharmacology 2021). PGx paves the way for more personalised medication prescription, especially for those patients experiencing side effects or lack of desired clinical effect (van Westrhenen et al. 2021,2025). Since 2017 a non-commercial outpatient clinic, Pharmacogenetics was set-up in Amsterdam, where psychiatric patients receive personalised medication advise. This is drafted using a comprehensive assessment including diagnosis, treatment and medication history, comorbid conditions and individual PGx profiles for patients who experienced inadequate treatment response or pronounced side effects from psychotropic medications. Aims & Objectives To educate the audience on Pharmacogenetics in Psychiatry and it’s potential and limitations To discuss guidelines to familiarize clinicians with clinical application of pharmacogenetics To discuss how to best implement in clinical psychiatry Method In most countries pharmacogenetic testing is only available commercially, or for scientific projects, but is not offered as part of routine clinical care by psychiatrists. In The Netherlands there is a non-commercial outpatient clinic that delivers personalised medication advise, partly based on pharmacogenetics. There are more and more initiatives to start up outpatient clinics in other EU countries. Essential elements to be taken into account will be discussed. Results Although the scientific evidence for the CYP2C19 and CYP2D6 genes seems strong enough to recommend clinical application, larger international and non-industry-funded implementation studies demonstrating feasibility and cost-effectiveness in real-world settings are lacking. Real-world settings include people that use more than one drug, for instance, which is something that the current guidelines do not yet cover. Possible obstacles in terms of feasibility include the availability of an efficient system to generate, deliver and implement genotyping in the clinical prescription of psychiatric medication. At this time, despite gene-dosing advice for antidepressants (SSRIs, SNRIs and TCAs) as well as for many antipsychotics, these are all prescribed to patients with almost no genotyping during treatment, not even when side effects occur or a psychopharmacotherapy is inefficacious. It is therefore recommended to consider genotyping when there is an indication (side effects or inefficacy of CYP2D6 and CYP2C19. Preemptive genotyping is therefore not recommended yet for psychotropic drugs. Discussion & Conclusions Integrating genetic data into medication management, especially for frequently involved enzymes like CYP2C19 and CYP2D6 can help optimise drug efficacy and tolerability. However, it is crucial that psychiatrists and other doctors familiarize themselve with this and are able to evaluate results themselves and incorporate them into clinical care. Simply taking over medication advise supplied by commercial companies that make use of non-disclosed algorithms is not recommended. References 1. U. Heilbronner, M. Rietschel, TG Schulze, R van Westrhenen, FS Goes, SN Deshpande. World Psychiatry 2025;24(3):455-456. 2. R. van Westrhenen, AH. Young AH, U. Heilbronner, JM., M. Ingelman-Sundberg, M. Jukic, J Kaprio, MJH Kas, R. Moldovan, MM. Nöthen, A. Philipsen, N. Shomron, E. Van der Eycken, E. Vieta. World Psychiatry 2025;24(1):141-142. 3. R. van Westrhenen, R., van Schaik, T. van Gelder, et. al. Frontiers in Pharmacology 2021, 12. https://doi.org/10.3389/fphar.2021.640032