Pharmacogenomics: The Future of Pharmacy

By Angela Tao

In a world where people with health issues, like depression or epilepsy, don’t need to wait months to find the best medication, the branch of pharmacology has expanded. Pharmacogenomics is a new area of medicine that focuses on tailoring medications to each patient [5]. It merges pharmacology with genomics, which is an area of science concerned with how genes interact with each other and the environment, to create the study of how genes affect people’s responses to drugs [5]. While aspects like diet, environment, and general health also impact reactions to medical treatments, genetics is the best predictor of how one’s body will process medication [6].

Predicting who’ll respond positively to medication, who’ll respond negatively, and who’ll not respond at all is difficult, which is why patients often spend months doing trial-and-error to find the right prescription for them. However, with pharmacogenomics, people are able to improve their treatment to save time and maintain their health. A specific liver enzyme called CYP2D6 accounts for 20-95% of variability in reactions to prescription drugs [1]. With over 160 variants of CYP2D6, a small difference in the gene can significantly affect how helpful the drug is [4]. Normally, people have two copies of the CYP2D6 gene, but some end up with up to thousands of copies of it [4]. As a result of an overabundance of the enzyme, drugs are processed extremely quickly and don’t have enough time to affect the body [4]. Conversely, there are also cases where versions of the gene cause drugs to take a greater effect than intended or be processed too slowly [4].

Through pharmacogenomics testing, doctors will ideally be able to prescribe a perfect dosage of the perfect drug for patients on the first try. But despite the rapid growth of this field in medicine, many drugs can’t be prescribed with pharmacogenomic testing. This is due to the fact that although “there are thousands of scientific articles linking a gene with a drug,... getting to the point where you could actually use that genetic information to make a prescribing decision requires an extremely high level of evidence, replication, validation, and mechanistic studies...” as stated by Mary Relling, the chair of pharmaceutical sciences at St. Jude Children’s Research Hospital [2]. Therefore, translating the significance of a pharmacogenetic study into information that doctors can use to prescribe drugs is a lengthy and difficult process. Presently, pharmacogenomics testing is only used with four drugs [3]. The branch of pharmacogenomics is still in its infancy, but once developed, it will play a large role in not only pharmacy, but also biotechnology.

References:

1. Evans, W., Author AffiliationsFrom St. Jude Children's Research Hospital and the University of Tennessee Colleges of Pharmacy and Medicine, & Goldstein, D. (2003, February 06). Pharmacogenomics - Drug Disposition, Drug Targets, and Side Effects: NEJM. Retrieved October 12, 2020, from https://www.nejm.org/doi/full/10.1056/NEJMra020526

2. Josh P. RobertsSep. 27, 2. (2019, March 29). Pharmacogenomics: Better drugs through better screening. Retrieved October 12, 2020, from https://www.sciencemag.org/features/2018/09/pharmacogenomics-better-drugs-through-better-screening

3. Pharmacogenomics FAQ. (n.d.). Retrieved October 12, 2020, from https://www.genome.gov/FAQ/Pharmacogenomics

4. Pharmacogenomics. (n.d.). Retrieved October 12, 2020, from https://www.nigms.nih.gov/education/fact-sheets/Pages/pharmacogenomics.aspx

5. Pharmacogenomics: What does it mean for your health? (2018, October 29). Retrieved October 12, 2020, from https://www.cdc.gov/genomics/disease/pharma.htm

6. What is pharmacogenomics?: MedlinePlus Genetics. (2020, September 22). Retrieved October 12, 2020, from https://medlineplus.gov/genetics/understanding/genomicresearch/pharmacogenomics/