Estimating the potential impact of implementing pre‐emptive pharmacogenetic testing in primary care across the UK

• Published in: British journal of clinical pharmacology Vol. 87; no. 7; pp. 2907 - 2925
• Main Authors: Youssef, Essra, Kirkdale, Charlotte L., Wright, David J., Guchelaar, Henk‐Jan, Thornley, Tracey
• Format: Journal Article
• Language: English
• Published: England 01.07.2021
• Subjects: community pharmacy; medicines optimisation; pharmacogenetics; pharmacogenomics; community pharmacy; pharmacogenomics; medicines optimisation; pharmacogenetics
• ISSN: 0306-5251; 1365-2125
• DOI: 10.1111/bcp.14704

Aims Pharmacogenetics (PGx) in the UK is currently implemented in secondary care for a small group of high‐risk medicines. However, most prescribing takes place in primary care, with a large group of medicines influenced by commonly occurring genetic variations. The goal of this study is to quantitatively estimate the volumes of medicines impacted by implementation of a population‐level, pre‐emptive pharmacogenetic screening programme for nine genes related to medicines frequently dispensed in primary care in 2019. Methods A large community pharmacy database was analysed to estimate the national incidence of first prescriptions for 56 PGx drugs used in the UK for the period 1 January–31 December 2019. These estimated prescription volumes were combined with phenotype frequency data to estimate the occurrence of actionable drug–gene interactions (DGI) in daily practice in community pharmacies. Results In between 19.1 and 21.1% (n = 5 233 353–5 780 595) of all new prescriptions for 56 drugs (n = 27 411 288 new prescriptions/year), an actionable drug–gene interaction (DGI) was present according to the guidelines of the Dutch Pharmacogenetics Working Group and/or the Clinical Pharmacogenetics Implementation Consortium. In these cases, the DGI would result in either increased monitoring, guarding against a maximum ceiling dose or an optional or immediate drug/dose change. An immediate dose adjustment or change in drug regimen accounted for 8.6–9.1% (n = 2 354 058–2 500 283) of these prescriptions. Conclusions Actionable drug–gene interactions frequently occur in UK primary care, with a large opportunity to optimise prescribing.