With the growing popularity of Pharmacogenetics, the field which is concerned with the impact of genetic variations on the response to drugs and their effectiveness, and the shift to personalized approach to health care, the debates concerning the advantages and disadvantages of individual genotyping for the treatment of cardiovascular diseases intensified. The individual genotyping can be effective for identifying the drug effectiveness in Cardiology and should become a part of the treatment decision making but should not be overestimated because it cannot be used in isolation from traditional methods.
The role of genetic analysis in identifying the arrhythmogenic diseases is debated though in particular cases when the underlying genetic defect may influence the outcome of the clinical management of patients significantly, the individual genetic testing is valuable and should be introduced into the clinical practice. After the discovery of causative genes of such diseases as the long-QT syndrome (LQTS) and hypertrophic cardiomyopathy (HCM), it was concluded that the individual genotyping is advantageous for the establishment of presymptomatic diagnosis and reproductive counseling (Priori & Napolitano, 2006, p. 1130). A number of studies on Pharmacogenetics have shown that the genetically determined variables can influence patients’ drug metabolism and blood concentration. Wilkins, Roses, & Clifford (2000) noted that “polymorphism in genes encoding P450 enzymes, N-acetyltransferase, and other key enzymes of drug metabolism are responsible for major inter-individual differences in blood concentrations of certain drugs” (p. 353). Thus, the individual genotyping can aid health care practitioners who develop the intervention strategies for the patients with cardiovascular diseases in determining the appropriate doses or even excluding some drugs for the purpose of preventing the risks of occurrence of adverse responds. By the present moment, several dozen drug-metabolizing enzymes have been identified by researchers (Swynghedauw, 2001, p. 205). Along with the regulation of the prescription measures, individual genotyping can be helpful for detecting the consequences of the intake of some drugs, such as the silent mutations in genes, for example (Swynghedauw, 2001, p. 208). These discoveries generate practitioners’ interest in transiting the method of individual genotyping for enhancing the drug effectiveness from bench to the bedside.
The key issues which are relevant to the sustainability of developing individual genotyping for drug effectiveness include the interest of pharmaceutical industry in the extension of the application of the achievements of pharmacogenetics in practice, along with the practical, technological and biological issues. The enthusiasm of the drug developers can be explained with the benefits of choosing appropriate patients for testing the new drugs for accelerating the processes of drug development and reducing the costs (Wilkins, Roses, & Clifford, 2000, p. 354). It is possible that the researchers will develop drugs for a specific group of patient population as well as identify the patients responding to medicine or have adverse events after the intake. Aimed at making the technology of individual genotyping operational, the pharmacogenetics specialists need to handle the issues of processing and storing the genotyping profiles. More research is needed for making the genetic analysis more reliable and helpful for the clinical practice. Despite all the benefits of the implementation pharmacogenomics as a powerful tool for identifying the interindividual variability of drug effectiveness, the optimization of the personalized medicine requires further advancements in the sphere of medical informatics and systematic approach to the processing of data and incorporating it into the intervention plans (Sadee & Dai, 2005, p. 214).
The recent researches in the sphere of pharmacogenetics and personalized medicine provide a profound literature support for the validity and sustainability of implementing the individual genotyping for identifying and regulating the drug effectiveness in Cardiology. Showing the validity of the adaptation of drugs to genotyping profiles as well as the future perspectives for the penetration of the method into the health care practice, Wilkins, Roses & Clifford (2000) covered the issues of human enzymes which are responsible for drug metabolism, particular genetic polymorphisms which are related to responses to particular drugs and the futuristic idea of attaching the genetic profile chip to drugs and patients’ case reports (p. 354). Acknowledging the benefits of individual genotyping and evaluating the sustainability of the approach critically, Swynghedauw (2001) admitted that “therapeutic prescription could better be adapted to a given patient by knowing a few selected polymorphisms directly or indirectly associated to drug-metabolizing enzymes or drug-targets” (p. 209). Sadee & Dai (2005) pointed at the critical role of pharmacogenomics data in the progress of understanding the drug effectiveness and responses, emphasizing the gradual character of the process (p. 214). Priori & Napolitano (2006) supported the importance of genetic analysis for the management of cardiovascular patients, admitting that the value of genetic testing depends upon the peculiarities of specific diseases (p. 1135).
The main aspects of the downside of the individual genotyping include economical, practical and ethical issues. The lack of reimbursements in the sphere causes the problems with conducting further investigation and providing more support for the effectiveness of the individual genotyping for evaluating the effectiveness of drugs and incorporating the data into the cardiology practice. At the same time, the role of the genetic analysis remains debatable because it has been proven that along with the genetic polymorphisms, there are a number of factors and processes which contribute to drug responses and require further complex research. The ethical issues of the susceptibility of genetics is another concern giving rise to the development of the debates which surround the theoretical problems of using genetic analysis for identifying drug effectiveness and incorporating it into the health care practice. Thus, the downside of the individual genotyping for evaluating drug effectiveness in Cardiology is not limited to practical, economical and technological problems but is also concerned with the processes in the society. Wilkins, Roses & Clifford (2000) noted that “not all drug responses are determined by inheritance and not all genetically determined responses will be easy to measure” (p. 354). It means that the individual genotyping cannot be used in isolation and the results of the genetic testing should be complemented with the data of traditional tests and used in conjunction with the established medical and ethical norms.
The recent advances in the sphere of pharmacogenetics have proven the value of individual genotyping for evaluating the drug effectiveness in Cardiology and other spheres of the treatment decision making processes. On the one hand, the benefits of the penetration of pharmacogenetics into the health care practice and the drug development process are undeniable. On the other hand, a number of studies have demonstrated the impact of additional factors along with the hereditary information on the interindividual responses to particular drugs. After further research of the issue, genetic analysis should become an integral element of the treatment decision making process, however, without underestimating the importance of traditional procedures.
Priori, S. & Napolitano, C. (2006). Role of genetic analyses in Cardiology. American Heart Association, 113: 1130 – 1135.
Sadee, W. & Dai, Z. (2005). Pharmacogenetics/genomics and personalized medicine. Human Molecular Genetics, 14 (2): 207 – 214.
Swynghedauw, B. (2001). Cardiovascular Pharmacogenetics and Pharmacogenomics. J Clin Basic Cardiol, 2: 205 – 210.
Wilkins, M., Roses, A., & Clifford, C. (2000). Pharmacogenetics and the treatment of cardiovascular disease. Heart, 84 (4): 353 – 354.