Let you understand personalized medication and drug metabolism gene testing

In life, we encounter the same disease, use the same medicine and the same dosage, why some people are cured, while others do not improve, some suffer from drug poisoning, and even a very small number of people are threatened with life? This phenomenon is the individual difference in drug response. Have you encountered a similar situation? Let us learn about the knowledge related to personalized medication and drug metabolism gene testing.

1. What is personalized medicine?

A safe, reasonable, effective and economical drug treatment plan is formulated based on the comprehensive consideration of each patient's drug metabolism gene type, gender, age, weight, physiological characteristics, pathological characteristics, other drugs currently being taken, etc. Therefore, the purpose of drug gene testing is to predict drug efficacy and adverse reactions based on individual genetic information, so as to adjust the dosage or change the type of medication to improve drug efficacy and avoid or reduce adverse drug reactions.

2. What is drug metabolism gene testing?

After the drug enters the human body, it goes through four processes of absorption, distribution, metabolism and excretion, and is slowly released and excreted in the body. In this process, metabolic enzyme genes, transporter genes, receptor genes, toxicity-related genes, etc. directly or indirectly affect the drug's target, the rate of drug metabolism, and the concentration of the drug in the body, resulting in different sensitivity and side effects of each person to the drug. By testing the genes of drug-metabolizing enzymes, drug binding targets, and transporters, it is possible to determine the metabolic rate of the drug in the human body, whether it will cause adverse reactions, and the effectiveness of the drug. In layman's terms, drug metabolism gene testing uses special equipment to analyze the information in your DNA molecules through blood samples, understand your genetic information, predict the body's risk of a certain disease or the metabolic transport capacity and sensitivity of the drug's target, so as to achieve the purpose of predicting disease risks and guiding clinical precision medication.

3. Which groups of people are suitable for drug metabolism gene testing?

① People for whom drug treatment is ineffective or ineffective;

② People with a history of adverse drug reactions;

③ People with a family history of adverse drug reactions;

④ People who intend to use drugs that may induce adverse reactions;

⑤ People with chronic diseases who need long-term medication;

⑥ People at risk of diseases that are more affected by genes;

4. Is it necessary to conduct genetic testing during drug use?

There are two requirements for drugs that require personalized treatment through drug genetic testing:

The first is “must”, which refers specifically to some targeted drugs that cannot be used without pharmacogenomic information.

The second is “recommendation”, which refers to other drugs that can usually be used but are not accurate. After using drug gene testing technology, accurate treatment can be achieved.

5. How to use genetic testing reports?

① With the help of genetic testing reports, we can gain insight into our own genetic strengths and weaknesses, estimate potential disease risks, and plan health management strategies accordingly.

②Personalized drug gene testing can help us understand the metabolic pathways and mechanisms of action of drugs in the body, thereby predicting the efficacy and adverse reactions of drugs. Taking clopidogrel as an example, a key test item is the detection of CYP2C19 gene polymorphism. This is because the enzyme encoded by this gene is an indispensable part of clopidogrel metabolism and is directly related to the efficacy of the drug. For the CYP2C19 gene polymorphism test of clopidogrel, the results can be roughly divided into three types: wild type (also known as normal type), heterozygous mutant type and homozygous mutant type. The wild type means that the individual can metabolize clopidogrel normally to ensure that the drug has a good therapeutic effect; the heterozygous mutant type indicates that the individual's ability to metabolize clopidogrel is weakened, or the dosage of the drug needs to be adjusted; and the homozygous mutant type shows that the individual's metabolism of clopidogrel is almost ineffective, and other drugs may need to be considered as alternatives.

③ Ability to gain in-depth insights into one's own uniqueness in the field of nutritional metabolism, and accordingly plan a nutritional supplementation strategy that suits individual needs. For example, for folic acid, common testing items include testing of folic acid metabolism-related genes such as MTHFR and MTRR. Mutations in these genes affect the metabolism and utilization of folic acid, thereby increasing the risk of cardiovascular disease, neural tube defects and other diseases. Based on the test results, doctors can provide patients with personalized nutritional advice and drug treatment plans.

6. How is drug gene testing done? What should the test subject pay attention to during the test?

During the test, only 2-5ml of whole blood specimens are needed to carry out various drug gene tests. Blood sampling does not require fasting, and the same drug gene test only needs to be done once in a lifetime. Currently, many drugs need to determine the individual metabolic type. For example, drugs for the treatment of hypertension, hyperlipidemia, diabetes, depression, asthma, antipsychotics, chemotherapy, etc. involve multiple different genes in their metabolism. Therefore, when formulating an individualized medication plan, genetic testing of patients can be used to select appropriate drugs and dosages, thereby avoiding drug toxicity and side effects and avoiding ineffective medication.

Regarding individualized drug therapy, a multidisciplinary medical diagnosis and treatment model has been initially formed, but there is still a long way to go in terms of how to interpret genetic testing and therapeutic drug concentration results in combination with the patient's clinical indications and determine safe and effective dosages.

References

[1]Magavern EF, Megase M, Thompson J, et al. Pharmacogenetics and adverse drug reports: Insights from a United Kingdom national pharmacovigilance database[J]. PLoS medicine, 2025, 22(3): e1004565

[2] Chen Jing. Individualized drug gene testing opens a "new era of precision medicine"[N]. People's Political Consultative Conference News, 2024-12-04(010).

[3] Wang Chen. Precision medicine: outline of drug therapy[M]. Beijing: People's Medical Publishing House, 2016:10.

[4] Qian Haoying, Li Rong, Hou Xiaoqun, et al. Analysis and application of drug gene detection results[J]. Pharmacy and Clinical Research, 2020, 28(06): 438-442.

[5] Ji Hongyu, Yu Yang, Cai Benzhi. Progress and prospects of clinical drug individualized treatment technology[J]. Progress in Pharmaceutical Sciences, 2020, 44(06): 404-410.

Author: Cao Longbin, Department of Medical Laboratory, The Seventh Affiliated Hospital of Southern Medical University