Background and Importance Pharmacogenetics evaluates how genetic variations influence drug responses. Nowadays, genetic tests have advanced, become more affordable, and its integration are supported by stronger clinical evidence. Guidelines such as those from CPIC and resources like PharmGKB facilitate genotype-based prescribing. Organisations like the FDA promote genetic testing before initiating certain medications. Preventive pharmacogenetic panels seems promising, but further research on biomarkers and diverse populations is needed.

Aim and Objectives This review examines recent evidence on the genotype-drug response relationship and its application in clinical practice.

Material and Methods A systematic search was conducted on PubMed to identify articles investigating the genotype-drug response relationship. The search strategy included terms such as ‘pharmacogenetics,’ ‘personalised treatment,’ ‘precision medicine,’ ‘dose adjustment,’ ‘individualised dosing,’ ‘clinical routine,’ and ‘clinical practice.’ Studies such as clinical trials, observational studies, and meta-analyses were included. The initial search yielded a total of 136 articles published between 2013 and 2023 for analysis.

Results 49 articles were included for the final analysis. The characteristics of the articles are explained in table 1.

A relationship between genetic polymorphisms and drug response or toxicity was found for drugs such as opioids, GLP-1 agonists, tacrolimus, oral anticoagulants, oral antineoplastics, atypical antipsychotics, efavirenz, clopidogrel, lamotrigine, anti-TNFα agents, voriconazole, SSRIs, or statins, among others. However, for drugs like metformin, quetiapine, irinotecan, bisoprolol, and anti-VEGF agents, no statistically significant association between genotype and response was found.

Conclusion and Relevance The studies analysed in this review suggest a strong correlation between genetic variability and individual drug responses, supporting the use of pharmacogenetics for treatment optimisation. However, for certain drugs like metformin, quetiapine, etc., the influence of genotype on their response remains unclear. More studies with larger sample sizes, greater ethnic diversity, and consideration of non-genetic factors are needed. Lack of standardisation in analysis methods and accessibility to genetic testing are significant challenges in this field. In summary, pharmacogenetics shows immense potential in personalised medicine, but further research is required.

Conflict of Interest No conflict of interest.