Pharmacogenomic markers of metoprolol and α-OH-metoprolol concentrations: a genome-wide association study.

Few genome-wide association studies (GWASs) have been conducted to identify predictors of drug concentrations. The authors therefore sought to discover the pharmacogenomic markers involved in metoprolol pharmacokinetics. The authors performed a GWAS of a cross-sectional study of 993 patients from the Montreal Heart Institute Biobank taking metoprolol. A total of 391 and 444 SNPs reached the significance threshold of 5 × 10 for metoprolol and α-OH-metoprolol concentrations, respectively. All were located on chromosome 22 at or near the gene, encoding CYP450 2D6, metoprolol's main metabolizing enzyme. The results reinforce previous findings of the importance of the locus for metoprolol concentrations and confirm that large biobanks can be used to identify genetic determinants of drug pharmacokinetics at a GWAS significance level.