What is pharmacogenomics?
- Pharmacogenetics (also known as pharmacology) is the study of how our genetic factor influence our response to medications. The term pharmacogenomics comes from the words pharmacology (the study of how drugs work) and genomics (the study of genes and their functions).
- Pharmacogenomics is part of precision medicine. It is personalized treatment based on genes, environment, and lifestyle. Pharmacogenomics can help your doctor prescribe a medication with fewer side effects or that is more effective for you.
- Currently, doctors use pharmacogenomics only for a limited number of diseases and medications. For example, some medications for HIV, certain cancers, depression, and heart disease. However, this area of medicine is changing and evolving rapidly. Researchers hope that pharmacogenomics may soon help doctors choose more effective medications to treat many common diseases.
How do genes influence how medications work?
Your genes give instructions to the cells in your body. Genes are involved in the manufacture of protein molecules known as enzymes. Enzymes perform countless functions, including breaking down (metabolizing) drugs. People who don’t respond to drugs as expected may have genetic differences that affect the amount of enzyme they produce or how effective it is. If the body breaks down a drug too quickly, too slowly, or not at all, the usual dose won’t be as effective. The drug may reason serious side effects or even be ineffective at treating a condition.
What is a pharmacogenomic test?
A pharmacogenomic test is a hereditary test that analyzes one or more genes to detect specific changes that affect drug absorption. For a pharmacogenomic test, doctors typically use a blood sample or a mouth swab. The doctor sends the sample to a laboratory, where a technician analyzes your DNA for specific changes. The gene or genes selected depend on the test ordered by the doctor, the condition(s) being treated, and the medications being considered.
When might you need pharmacogenomic testing?
Pharmacogenomic testing may be available if you take medications for certain medical conditions. Below are some examples (but not all) of reasons why your healthcare provider might recommend pharmacogenomic testing:
High cholesterol
Variants in the SLCO1B1 gene can cause muscle pain and weakness when taking certain statins to treat high cholesterol. These statins may include:
- Atorvastatin (Lipitor®).
- Fluvastatin (Lescol®).
- Lovastatin (Altoprev®).
- Pitavastatin (Livalo®).
- Pravachol®).
- Rosuvastatin (Crestor®).
- Simvastatin (Zocor®).
- Depression
Variations in the CYP2D6 and CYP2C19 genes can affect how quickly certain antidepressants are broken down in the body.
These include:
Amitriptyline (Elavil®), a tricyclic antidepressant.
Selective serotonin reuptake inhibitors (SSRIs), such as citalopram (Celexa®), escitalopram (Lexapro®), sertraline (Zoloft®), paroxetine (Paxil®), and fluvoxamine (Luvox®).
Venlafaxine (Effexor®), an SSRI.
Cancer
If you take medications for certain types of cancer, you may benefit from pharmacogenomic testing, including:
- Breast cancer: Trastuzumab (Herceptin®) is only effective in people with HER2-positive breast cancer. These tumors have a genetic profile that causes overproduction of a protein called HER2. Acute lymphoblastic leukemia (ALL): Taking mercaptopurine (Purinethol®) at the usual dose in patients with low levels of the enzyme thiopurine methyltransferase (TPMT) can cause thoughtful side effects and increase the risk of infection.
- Colon cancer: Patients with UGT1A1 enzyme deficiency may experience severe diarrhea and an increased risk of infection when taking irinotecan (Camptosar®).
- Taking the chemotherapy drug fluorouracil, 5-FU (Adrucil®), at the usual dose in patients with low levels of the enzyme dihydropyrimidine dehydrogenase (DPD) can source serious side effects. Doctors may recommend this drug for colorectal, breast, stomach, and pancreatic cancer.
Blood clot prevention
- People with certain genetic variants require lower doses of the blood thinner warfarin (Kumidan®).
- Changes in the activity of the CYP2C19 enzyme in the liver can render clopidogrel (Plavix®) ineffective. This is an antiplatelet drug.
HIV
- Alterations in the HLA-B gene can cause a severe skin reaction to abacavir (Ziagen®).
- Alterations in the CYP2B6 gene can increase the risk of side effects from efavirenz (Sustiva®), such as neurological disorders.
Immune System Disorders
- You may benefit from pharmacogenomic testing if you take immunosuppressants:
- Alterations in the TPMT and NUDT15 proteins can suppress bone marrow activity if you take azathioprine (Imuran®) after a kidney transplant and in immune-related diseases, such as multiple sclerosis.
- Alterations in the CYP3A5 enzyme may increase the risk of organ transplant rejection if you take tacrolimus (Prograf®) after an organ transplant.
- What are the potential benefits of pharmacogenomic testing? By continuing to study and use pharmacogenomics, researchers and healthcare professionals can gain numerous benefits, including:
- Increased safety: Healthcare professionals can avoid prescribing medications that cause dangerous side effects or overdoses in some people. Increased efficiency and reduced healthcare costs: Knowing which medications are likely to be effective or not allows healthcare specialists to prescribe the most effective ones first.
- Targeted drug development: Some conditions are caused by specific changes (variants) in a gene. Pharmacogenomics can help researchers find new drugs that directly target these genetic changes.
What are the potential limitations of pharmacogenomics?
- While your genetic makeup is important in determining the best treatment for many conditions, it doesn’t fully explain how your body processes medications.
- Healthcare professionals must consider other factors when choosing the right drug therapy, such as:
- Other medications: Your current medications may affect the breakdown of other medications.
- Other medical conditions: Some medical conditions may affect the breakdown of medications in your body.
- Lifestyle: Your lifestyle, including your diet, the amount of exercise you get, and your tobacco and alcohol use, can affect the breakdown of medications.
- Other challenges in the expansion and use of pharmacogenomics include:
- Cost: The cost of pharmacogenomic taxing is decreasing, but the costs or actual costs for each person often vary depending on health insurance coverage.
- Access: Your access to certain genetic tests may be limited depending on where you live or the type of healthcare professionals providing care.
Pharmacogenomics Overview
Pharmacogenomics is a revolutionary approach to healthcare that links an individual’s genetic makeup with their response to medications. This field improves the safety, efficacy, and personalization of drug therapy, minimizing adverse reactions and improving treatment outcomes. As our sympathetic of genetics and biotechnology advances, pharmacogenomics is flagging the way for precision medicine, where treatments are tailored to apiece patient’s unique genetic profile. To achieve its full potential, continued investment in research, healthcare education, and integration into clinical practice is essential. As barriers such as cost, accessibility, and ethical considerations are eliminated, pharmacogenomics will become an integral part of modern medicine, leading to more effective and personalized healthcare for all.
Frequently Asked Questions
1. What is pharmacogenomics?
Pharmacogenomics is the study of how a person’s genes influence their response to drugs. It combines pharmacology (the science of drugs) and genomics (the study of genes) to develop safer and more effective drugs tailored to individual genetic profiles.
2. How does pharmacogenomics work?
Pharmacogenomics analyzes specific genes involved in drug metabolism, transport, and targets. Based on genetic variations, it predicts a person’s response to a drug: whether it will be effective, ineffective, or cause side effects.
3. Why is pharmacogenomics important?
It helps to:
- Reduce adverse drug reactions
- Increase treatment effectiveness
- Personalize dosage and drug selection
- Avoid trial and error in prescribing
- Improve overall patient safety and treatment outcomes
4. Which drugs are affected by pharmacogenomics?
Many medications are affected by genetics, including:
- Anticoagulants (e.g., warfarin, clopidogrel)
- Antidepressants (e.g., SSRIs)
- Pain relievers (e.g., codeine)
- Anticancer drugs (e.g., tamoxifen, targeted therapy)
- Immunosuppressants (e.g., azathioprine)
5. How is a pharmacogenomic test performed?
The test usually involves a simple blood test or a cheek swab. DNA is analyzed to look for specific genetic variants that affect how the patient metabolizes and responds to the medication.
6. Who should consider pharmacogenomic testing? It may be recommended for:
- Patients with adverse drug reactions
- People starting long-term or high-risk treatment
- People with a family history of drug sensitivity
- Cancer patients before starting targeted therapy
7. Does health insurance cover pharmacogenomic testing?
Coverage varies by country, healthcare provider, and health plan. In some cases, pharmacogenomic testing is covered if it is medically necessary or related to specific medications.
8. What is the difference between pharmacogenomics and pharmacogenetics?
Pharmacogenetics studies the effects of individual genes on drug response.
Pharmacogenetics studies the entire genome and how multiple genes interact to affect drug response.
9. Are pharmacogenomic test results permanent?
Yes. Since genes don’t change over time, pharmacogenomic testing is typically performed once in a lifetime and can guide medication choices throughout life.
10. Can pharmacogenomics replace the need for medical care?
No. While pharmacogenomics provides valuable information, it is only one part of a comprehensive medical evaluation. Doctors also consider other factors, such as age, weight, liver and kidney function, lifestyle, and medications.