PGx: Genetic Testing to Predict Drug Metabolism

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Pharmacogenetic (PGx) testing looks at how your genes affect the way your body responds to medications. Everyone processes drugs a little differently, and this test helps identify which medications are likely to work best for you—and which ones may cause side effects or be less effective.

Whether you’re dealing with ongoing health issues or about to start a new prescription, PGx testing can give you and your healthcare provider more clarity and confidence in choosing the right treatment.

You can order a PGx test online through our secure system without needing to visit a clinic.

You can order a pharmacogenetic test online through our secure platform—no clinic visit required.

Test Description

The PGx (Pharmacogenomic) Test analyzes specific genes involved in drug metabolism to identify genetic variations that can influence how your body responds to a wide range of medications. These variations can affect how quickly or slowly your body breaks down drugs, how well a medication works for you, and whether you’re at higher risk for side effects or adverse reactions.

Some people metabolize certain drugs too quickly, leading to reduced effectiveness. Others process them too slowly, which can cause medications to build up in the body and increase the risk of side effects. PGx testing helps uncover these patterns by examining genes such as CYP2D6, CYP2C19, and others that are key to drug metabolism.

With this information, your healthcare provider can make more informed decisions about which medications to prescribe and at what dose—helping tailor treatment to your genetic profile. This is especially useful for medications used in mental health, pain management, cardiovascular care, and gastrointestinal conditions.

The PGx test is done with a simple cheek swab or saliva sample and only needs to be done once in your lifetime, since your genetic profile does not change.

Markers

• 12q15: This region may affect how the immune system responds to certain medications and has been studied in relation to autoimmune and inflammatory conditions.
• 4q25: Variants in this area are linked to heart rhythm disorders, such as atrial fibrillation, which can influence decisions about certain heart medications.
• ADH1B: Affects how the body breaks down alcohol. Some people with this variant metabolize alcohol faster, which can lead to unpleasant reactions like flushing.
• ADRA2A: This gene influences how the nervous system responds to stress and certain medications for ADHD, blood pressure, and mood.
• ALDH2: Plays a major role in how the body processes alcohol. Some people with this variant experience flushing, nausea, or rapid heartbeat after drinking.
• ANKK1: Often studied with the dopamine system, this marker may influence response to medications affecting motivation, mood, or addiction.
• APOE: Associated with how the brain handles cholesterol and inflammation. Certain variants may affect memory, cognitive decline, or response to brain-active drugs.
• ATM: Involved in DNA repair. Variations may affect how the body tolerates radiation or certain chemotherapy drugs.
• BDNF gene: Supports brain cell growth and communication. Variants may influence mood, memory, and how well some psychiatric medications work.
• CACNA1C: This gene affects how calcium moves in and out of brain cells. It has been linked to mood regulation and response to psychiatric medications.
• COMT: Helps break down dopamine and other brain chemicals. Variants can influence stress response, mood, and how people react to stimulants or pain medications.
• CYP1A2: Impacts how the liver breaks down caffeine and some medications. People with certain variants may be slow or fast metabolizers.
• CYP2B6: Affects how certain antidepressants, antiretrovirals, and anesthetics are processed in the body.
• CYP2C19: Plays a role in breaking down medications like proton pump inhibitors, antidepressants, and the blood thinner clopidogrel.
• CYP2C9: Influences how the body processes medications like warfarin, NSAIDs, and some diabetes drugs.
• CYP2D6: One of the most important enzymes in drug metabolism. Affects how many antidepressants, opioids, and beta blockers are processed.
• CYP3A4: A major enzyme that helps metabolize many common medications. Differences can affect drug clearance and dosing.
• CYP3A5: Works alongside CYP3A4 but varies more widely between people. It can influence how medications like tacrolimus are handled.
• CYP4F2: Plays a role in vitamin K metabolism and may influence dosing for the blood thinner warfarin.
• F13A1: Related to blood clot stability. Variants may slightly influence clotting risk or response to clot-related medications.
• FKBP5: Regulates stress hormones. Variations may affect how people respond to antidepressants or recover from trauma.
• G6PD gene: Involved in red blood cell protection. People with certain variants may have a risk for anemia when exposed to specific drugs or foods.
• GRIK1: This gene influences how certain brain receptors respond to mood medications, including those used for alcohol dependence.
• GRIK4: Related to glutamate signaling in the brain. Variants may influence response to antidepressants.
• GRIN2B: Affects brain cell signaling through NMDA receptors. Studied in relation to cognition, mood, and neurodevelopment.
• HLA-A: Certain variants may raise the risk of severe allergic reactions to specific drugs, such as some HIV medications.
• HLA-B: A well-known marker for hypersensitivity reactions to drugs like abacavir or carbamazepine.
• HTR2A: Influences serotonin activity in the brain. Variants may affect response to SSRIs and other mood-related medications.
• HTR2C: Also part of the serotonin system. Has been linked to weight gain risk from some psychiatric medications.
• IFNL3: Involved in immune response. May influence how people respond to treatments for viral infections like hepatitis C.
• IL6: A marker of inflammation. Certain variants may affect how the body reacts to stress, infection, or chronic inflammatory conditions.
• ITGB3: Involved in blood clotting. Variants may influence how the body responds to certain antiplatelet drugs like aspirin.
• MTHFR: Helps process folate and maintain healthy homocysteine levels. Variants may affect cardiovascular risk and response to folate-containing supplements or medications.
• NUDT15: Affects breakdown of some chemotherapy drugs, such as mercaptopurine. Variants can raise risk for serious side effects.
• OPRD1: Involved in how the brain responds to opioids. Variants may influence pain tolerance and risk of opioid dependence.
• OPRK1: Affects kappa opioid receptors, which are involved in pain perception and emotional regulation.
• OPRM1: Key gene for opioid receptors. Variants may affect how people respond to pain medications like morphine or codeine.
• SLCO1B1: Influences how statins (cholesterol-lowering drugs) are transported in the liver. Certain variants may increase the risk of muscle side effects.
• TPMT: Helps process thiopurine drugs used in autoimmune and cancer treatment. Variants can lead to serious toxicity if standard doses are used.
• VKORC1: Plays a role in vitamin K recycling. Variants help determine sensitivity to warfarin and guide dosing to reduce bleeding risk.

Who Should Consider This Test?

• People taking multiple medications: PGx testing can help identify drug interactions and guide safer prescribing for those on complex medication regimens.
• People who have had unusual side effects or poor response to medications: Genetic differences may explain why standard doses of certain drugs do not work well or cause unexpected reactions.
• People starting antidepressants, antipsychotics, or mood stabilizers: PGx testing can guide medication choice and dosing based on how the body metabolizes psychiatric drugs.
• People being treated for chronic pain: Genes like CYP2D6 and OPRM1 influence how pain medications such as opioids are processed, which may affect pain control and risk of dependence.
• People prescribed blood thinners: Variants in genes like CYP2C9 and VKORC1 can affect warfarin sensitivity, requiring dose adjustments to avoid bleeding or clotting risks.
• People with a history of medication allergies or serious reactions: Markers like HLA-B can predict life-threatening drug hypersensitivity, allowing providers to avoid risky prescriptions.
• People with a family history of medication-related complications: Shared genetic traits may influence drug metabolism and response across related individuals.
• People undergoing cancer treatment with chemotherapy or targeted therapies: Some genes, such as TPMT and NUDT15, influence how well certain cancer drugs are tolerated.
• People with liver enzyme differences identified in past lab testing: PGx can help explain unusual liver metabolism patterns and guide future drug choices.

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The information provided in this article is for educational purposes only and is not intended to diagnose, treat, cure, or prevent any disease. Functional medical tests and nutrition-related labs should be used as tools to support health and wellness under the guidance of a qualified healthcare provider. Results from these tests should not replace professional medical advice or be interpreted without consulting a licensed practitioner familiar with your health history and needs. Always consult your doctor or dietitian before making changes to your diet, supplements, or health management plan.