Introduction
Pharmacogenomics has been described as the study of differential responses to pharmacological treatment due to heredity, which has drawn attention to personalized medicine [1-5]. The genetically determined inter-individual variability in enzyme activity, receptors, transporters, and various other drug targets has been associated with the efficacy and toxicity of pharmaceutical treatment [6-9]. Polymorphisms, mutations, gene expression differences, and chromosomal abnormalities that cause changes in these targets may be the main reason for variations in the body’s reaction to drug exposure. Variability in drug efficacy and safety is explained by pharmacogenomics besides factors such as age, sex, body mass index, renal and liver functions, other diseases, and lifestyle differences [10-14].
Inter-individual variations in drug responses not only affect drug efficacy but also can lead to adverse drug reactions (ADRs) in patients. ADRs are associated with morbidity and mortality and are a burden to the healthcare system, accounting for a cost of almost 100 billion USD [7]. According to a prospective analysis, up to 6.5% of acute hospital admissions in the United Kingdom are still related to ADRs [16].
ADRs can be minimized by rational prescription and personalization of medicine for each patient, the precision of which can be increased by considering the pharmacogenomic information (PGx) during these processes. The European Commission published a guideline on the summary of product characteristics (SmPCs) in 2009, which emphasized that all available relevant PGx should be included in the SmPCs [17]. In 2015, a review of 517 pharmaceutical products approved for use by the European Medicines Agency (EMA) from 1995 to 2014 showed that the SmPCs of approximately 15% of medications consisted of PGx that directly impacted treatment [18]. Similarly, Frueh et al. performed a review of the labels of the drugs approved by the United States Food and Drug Administration (FDA) and estimated that almost one-fourth of patients in 2006 (approximately 8.8 million) were prescribed one or more drugs for which the label included PGx in the US [19]. We estimate that this number has increased considerably over time.
Providing adequate PGx of the drugs to patients has some ethical implications in terms of providing benefits, avoiding harm, mitigating risks, strengthening the trust in healthcare providers, and empowering patients, as the new-found scientific information in pharmacogenomics increases the moral responsibility to effectively transfer this information to patients. Therefore, the aim of this study was to determine if there are discrepancies among various agency-approved labels for the same active ingredient and where the labels approved by the Turkish Medicines and Medical Devices Agency (TMMDA) stand regarding the inclusion of PGx and discuss the ethical implications of SmPCs with inadequate and outdated information in the context of the principles of medical ethics.