Prospective use of CYP pharmacogenetics and medication analysis to facilitate improved therapy - a pilot study

An Analysis of Pharmacogenomic-Guided Pathways and Their Effect on Medication Changes and Hospital Admissions: A Systematic Review and Meta-Analysis

Ninety-five percent of the population are estimated to carry at least one genetic variant that is discordant with at least one medication. Pharmacogenomic (PGx) testing has the potential to identify patients with genetic variants that puts them at risk of adverse drug reactions and sub-optimal therapy. Predicting a patient's response to medications could support the safe management of medications and reduce hospitalization. These benefits can only be realized if prescribing clinicians make the medication changes prompted by PGx test results. This review examines the current evidence on the impact PGx testing has on hospital admissions and whether it prompts medication changes. A systematic search was performed in three databases (Medline, CINAHL and EMBASE) to search all the relevant studies published up to the year 2020, comparing hospitalization rates and medication changes amongst PGx tested patients with patients receiving treatment-as-usual (TAU). Data extracted from full texts were narratively synthesized using a process model developed from the included studies, to derive themes associated to a suggested workflow for PGx-guided care and its expected benefit for medications optimization and hospitalization. A meta-analysis was undertaken on all the studies that report the number of PGx tested patients that had medication change(s) and the number of PGx tested patients that were hospitalized, compared to participants that received TAU. The search strategy identified 5 hospitalization themed studies and 5 medication change themed studies for analysis. The meta-analysis showed that medication changes occurred significantly more frequently in the PGx tested arm across 4 of 5 studies. Meta-analysis showed that all-cause hospitalization occurred significantly less frequently in the PGx tested arm than the TAU. The results show proof of concept for the use of PGx in prescribing that produces patient benefit. However, the review also highlights the opportunities and evidence gaps that are important when considering the introduction of PGx into health systems; namely patient involvement in PGx prescribing decisions, thus a better understanding of the perspective of patients and prescribers. We highlight the opportunities and evidence gaps that are important when considering the introduction of PGx into health systems.

Pharmacotherapeutic Follow-up and Pharmacogenetics of CYP2C9 and CYP3A4 in Antihypertensive Therapy: A Pilot Study in a Community Pharmacy

No pharmacogenetic studies have yet been conducted in community pharmacies, despite pharmacogenetics being an emerging discipline. Pharmacotherapeutic follow-up (PFU) was performed for 6 months in 37 patients receiving antihypertensive treatment, and they were genotyped for variant alleles *2 and *3 in the CYP2C9 gene and *1B in CYP3A4. Systolic blood pressure, cardiovascular risk, and adherence improved with PFU. Most of the interactions between drugs were represented by concurrent administration of statins and calcium channel blockers, which both use CYP3A4 for their metabolism. Heterozygotic patients for the CYP2C9*2 allele showed higher mean heart rate values after PFU than homozygous patients (73.4 ± 10.0 pulse/min vs 66.2 ± 10.6 pulse/min, respectively; P = .048). Carriers of CYP2C9*2 showed a tendency to less frequent negative outcomes associated with medication due to inefficacy than homozygous patients (50% vs 78.9%, respectively; P = .072). Pharmacogenetics and PFU can be used in community pharmacies to carry out a more exhaustive study of medication in hypertensive outpatients.