Adverse drug reactions (ADRs) are a major health concern worldwide. There are multiple causes of ADRs, some of which are preventable. Pharmacogenomics accounts for ≈80% variability in drug efficacy and safety. Over 400 genes are clinically relevant in drug metabolism, and ≈200 pharmagenes are associated with ADRs. The condition of extensive metabolizer in the Caucasian population is lower than 20%, and about 60% of patients are exposed to potential ADRs. Areas covered: Important topics related to pharmacogenomics in drug efficacy and safety are covered, including: (i) major components of the pharmacogenomic machinery; (ii) epigenetic regulation of pharmagene expression; and (iii) pharmacogenomics-related ADRs of different drug categories. Expert opinion: The Regulatory Agencies should make recommendations to the pharmaceutical industry in favor of the introduction of pharmacogenomics in drug development and the inclusion of pharmacogenomic information on drug labels, with specific warnings for the population at risk. Educational programs are fundamental for drug prescribers to become familiar with personalized treatments. Pharmacogenetic testing should be gradually introduced into medical practice. ADRs can be reduced not only by adherence to prescribing guidelines, suitable monitoring and regular medication review, but also by the implementation of pharmacogenomic procedures in the clinical setting.
Keywords: ABCB1; ADRs; CYP2C19; CYP2C9; CYP2D6; epigenetics; metabolic genes; pharmacogenomics; transporter genes; trigenic genotypes.