From the lab to the prescription pad: genetics, CYP450 analysis, and medication response

Utility of pharmacogenetic testing to optimise antidepressant pharmacotherapy in youth: a narrative literature review

Pharmacogenetics (PGx) is the study and application of how interindividual differences in our genomes can influence drug responses. By evaluating individuals' genetic variability in genes related to drug metabolism, PGx testing has the capabilities to individualise primary care and build a safer drug prescription model than the current "one-size-fits-all" approach. In particular, the use of PGx testing in psychiatry has shown promising evidence in improving drug efficacy as well as reducing toxicity and adverse drug reactions. Despite randomised controlled trials demonstrating an evidence base for its use, there are still numerous barriers impeding its implementation. This review paper will discuss the management of mental health conditions with PGx-guided treatment with a strong focus on youth mental illness. PGx testing in clinical practice, the concerns for its implementation in youth psychiatry, and some of the barriers inhibiting its integration in clinical healthcare will also be discussed. Overall, this paper provides a comprehensive review of the current state of knowledge and application for PGx in psychiatry and summarises the capabilities of genetic information to personalising medicine for the treatment of mental ill-health in youth.

Identification of biomarkers to diagnose diseases and find adverse drug reactions by metabolomics

Metabolomics has been widely used for investigating the biological functions of disease expression and has the potential to discover biomarkers in circulating biofluids or tissue extracts that reflect in phenotypic changes. Metabolic profiling has advantages because of the use of unbiased techniques, including multivariate analysis, and has been applied in pharmacological studies to predict therapeutic and adverse reactions of drugs, which is called pharmacometabolomics (PMx). Nuclear magnetic resonance (NMR)- and mass spectrometry (MS)-based metabolomics has contributed to the discovery of recent disease biomarkers; however, the optimal strategy for the study purpose must be selected from many established protocols, methodologies and analytical platforms. Additionally, information on molecular localization in tissue is essential for further functional analyses related to therapeutic and adverse effects of drugs in the process of drug development. MS imaging (MSI) is a promising technology that can visualize molecules on tissue surfaces without labeling and thus provide localized information. This review summarizes recent uses of MS-based global and wide-targeted metabolomics technologies and the advantages of the MSI approach for PMx and highlights the PMx technique for the biomarker discovery of adverse drug effects.

Pharmacogenetic Testing: Why Is It So Disappointing?

Pharmacogenetic testing to aid in making decisions about prescribing medications was approved by the U.S. Food and Drug Administration in 2005 and gradually became a common practice. However, an innovation that was thought to help individualize prescribing psychotropic medications with fewer trials and errors soon became a disappointment to clinicians. Current pharmacogenetic testing assesses how the liver metabolizes drugs through the cytochrome p 450 system; however, much of the variability in how a drug affects an individual also relies on the pharmacodynamics of the drug (i.e., the specific ways the drug changes the body). The current article discusses the advantages and disadvantages of pharmacogenetic testing to aid in prescribing psychotropic medications. [Journal of Psychosocial Nursing and Mental Health Services, 57(4), 9-12.].

Pharmacogenomics and Psychiatric Nursing

The treatment of mental illness is often done on a trial-and-error basis and achieving therapeutic benefits from a medication is not always guaranteed. Pharmacogenomics explores the role of gene-gene interactions and interindividual responses to a drug and may be promising in the guidance of pharmacotherapeutic options. In the present study, the impact of pharmacogenomic testing in management of mental health medication was investigated. Participants were identified at a local outpatient mental health facility through convenience sampling. Retrospective chart review included medication history, adverse drug reactions, pharmacogenomic history, and demographic data including insurance coverage. Chart review focused on six months pre- and post-pharmacogenomic for a comparison with the patient serving as their own control. Results indicate a high incidence of alterations in two specific cytochrome enzymes, CYP2D6 and CYP2C19. In total, 82% of the sample had variations with CYP2D6, while 64% of individuals had variations with CYP2C19. In total, 91% of patients tested received Medicaid or Medicare. Post-pharmacogenomic testing, all patient drug regimens were modified, and all reported less adverse side effects. Moreover, advanced practice nurse providers educated patients about the availability of genetic testing, initiated testing and provided care based on findings. These results demonstrate the utility of genetic testing in the realm of mental health. Future directions involve further exploring the benefits of pharmacogenomic testing in this vulnerable population.

Principles of precision medicine and its application in toxicology

Precision medicine is an approach to developing drugs that focuses on employing biomarkers to stratify patients in clinical trials with the goal of improving efficacy and/or safety outcomes, ultimately increasing the odds of clinical success and drug approval. Precision medicine is an important tool for toxicologists to utilize, because its principles can be used to decide whether to pursue a drug target, to understand interindividual differences in response to drugs in both nonclinical and clinical settings, to aid in selecting doses that optimize efficacy or reduce adverse events, and to facilitate understanding of a drug's mode-of-action. Nonclinical models such as the mouse and non-human primate can be used to understand genetic variation and its potential translation to humans, and are available for toxicologists to employ in advance of drugs moving into clinical development. Understanding interindividual differences in response to drugs and how these differences can influence the drug's risk-benefit profile and lead to the identification of biomarkers that enhance patient efficacy and safety is of critical importance for toxicologists today, and in the future, as the fields of pharmacogenomics and genetics continue to advance.

Emerging applications of metabolomics in drug discovery and precision medicine

Metabolomics is an emerging 'omics' science involving the comprehensive characterization of metabolites and metabolism in biological systems. Recent advances in metabolomics technologies are leading to a growing number of mainstream biomedical applications. In particular, metabolomics is increasingly being used to diagnose disease, understand disease mechanisms, identify novel drug targets, customize drug treatments and monitor therapeutic outcomes. This Review discusses some of the latest technological advances in metabolomics, focusing on the application of metabolomics towards uncovering the underlying causes of complex diseases (such as atherosclerosis, cancer and diabetes), the growing role of metabolomics in drug discovery and its potential effect on precision medicine.

Clinical implications of pharmacogenetic and microarray testing for advanced practice nurses

PURPOSE

The rapidly changing field of pharmacogenetics requires that advanced practice providers have a fundamental foundation in genetics and genetic testing on which new knowledge can be built. Testing for allelic variation in the well-researched Cytochrome P450 pathways and other pathways of drug metabolism is done through microarray testing. Understanding the process microarray testing provides a framework for understanding pharmacogenetic testing.

DATA SOURCES

Genetic, pharmacogenetic, and biotechnical literature is reviewed to explain the genetics and biotechnology behind testing for allelic variation. Clinical examples of applied pharmacogenetic testing in cardiology and psychiatry are provided from the nursing literature.

CONCLUSION

The advent and practical application of inexpensive and available testing aimed to identify genetic variations in individual patient metabolism of common and critical medications, necessitates that advanced practice registered nurses (APRNs) have a deeper understanding of the biotechnology involved in pharmacogenetic and pharmacogenomics testing.

IMPLICATIONS FOR PRACTICE

Providers with a working knowledge of the microarray testing method will have a framework for understanding which patients to test, what tests to order, and how to interpret the results of these genetic tests. APRNs need to increase their reliance on the interdisciplinary databases that maintain the most current and relevant knowledge of pharmacogenetics.

Pharmacogenomics in the nursing literature: an integrative review

BACKGROUND

Pharmacogenomics is a rapidly growing component of personalized health care, and nurses must be competent to deliver genomic-focused nursing care.

METHODS

We conducted an integrative review of pharmacogenomics in the nursing literature. A comprehensive search of the nursing literature was conducted using the key words pharmacogenomics and pharmacogenetics. A total of 47 unique articles were included.

RESULTS

Articles represented mainly narrative reviews, with limited discussions of the implications for nursing practice, education, or research. As such, they provide limited direction for advancing either clinical practice or scientific inquiry.

CONCLUSIONS

This review serves as a call to action for more systematic and empirical publications addressing pharmacogenomics in nursing practice, education, and research. Nurses must be involved in and contribute to interdisciplinary conversations and burgeoning clinical practice initiatives related to pharmacogenomics.