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Unlike Drug-Drug interactions, where one medication alters another’s effects, detecting Drug-Gene interactions requires pharmacogenomics (PGx) testing. This testing identifies genetic variations that can impact how a patient responds to medications. Without access to this genetic data, doctors may miss these important interactions.
Pharmacogenomics (PGx) testing can identify specific gene variations that affect how drugs interact with the body. This helps doctors detect potential Drug-Gene interactions, ultimately improving treatment outcomes, minimizing side effects or risks of toxicity, and reducing unpredictable drug responses and overall healthcare costs.
Let’s suppose you have high cholesterol and visit your doctor. After evaluating all crucial factors—such as age, sex, body mass index (BMI), pathology tests, lifestyle, medical history, allergies and sensitivities, medication history, and drug-drug interactions [5-12]—your doctor decides to prescribe a statin, such as atorvastatin, simvastatin, rosuvastatin, pravastatin, or lovastatin, to help lower your cholesterol.
While the prescribing decision is based on the important factors mentioned above, your doctor may still be unaware of any Drug-Gene interactions. This means your genes may affect your ability to produce the enzymes needed to metabolize the prescribed statin effectively. Due to genetic variations, you may metabolize the drug partially, rapidly, ultra-rapidly, or not at all. If your body does not metabolize the statin properly, it could lead to reduced effectiveness or an increased risk of side effects.
This is where a PGx test report becomes invaluable. It provides a comprehensive analysis, detecting genetic mutations in 18 specific genes that are analyzed for their impact on 116 medications, including those used in Psychiatry, Hematology, Neurology, Oncology, Pain Management, Cardiology, Gastroenterology, Infectious Diseases, Rheumatology, Organ Transplantation, General Practice, and other specialties. Based on these genetic variations, individuals are categorized into different metabolizer types—normal, poor, ultra-rapid, or intermediates—depending on their ability to process and break down medications in the body using enzymes [1].
Below is a detailed explanation of the different metabolizer types that your PGx report may indicate:
What Happens:
Ultra-rapid metabolizers process medications much faster than normal, which can cause the drug to leave the body before it has a chance to take effect, reducing its therapeutic efficacy. For drugs that rely on active metabolites (e.g., codeine metabolized to morphine), ultra-rapid metabolism may lead to toxic levels of these metabolites in the blood [1, 3]. The CYP2D6 enzyme is responsible for metabolizing codeine into its active form, morphine, which provides its analgesic (pain-relieving) effect [3].
Example:
In the context of Drug-Gene interactions, an example is the CYP2D6 gene and the drug codeine. Ultra-rapid metabolizers, who possess multiple copies of the CYP2D6 gene, convert codeine into its active form, morphine, at an accelerated rate. This rapid conversion can result in dangerously high levels of morphine in the bloodstream, increasing the risk of severe side effects such as respiratory depression, excessive sedation, or even fatal overdose [3].
Side Effects:
What Happens:
Individuals with intermediate metabolism process drugs slower than normal but faster than poor metabolizers. This results in a partial reduction in enzyme activity, leading to a moderate accumulation of the drug in the body. The effects are not as severe as in poor metabolizers but may still lead to an increased risk of side effects [4].
Example:
An example is the interaction between the CYP2C9 gene and the drug warfarin (a blood thinner). Intermediate metabolizers with reduced CYP2C9 enzyme activity process warfarin more slowly than normal, leading to a partial accumulation of the drug. This can result in a higher risk of bleeding, as the drug stays in the system longer than expected, though not as severe as in poor metabolizers [4].
Side Effects:
What Happens:
In rapid metabolizers, enzyme activity is increased, so medications are processed and eliminated from the body at an accelerated pace. This can lead to suboptimal drug levels, reducing the intended effect of the medication. The patient may not experience the full therapeutic benefits because the drug doesn’t remain in the body long enough to be effective [1].
Example:
An example of rapid metabolism occurs with the CYP2C19 gene and the drug omeprazole, a common proton pump inhibitor used to treat acid reflux. People who are rapid metabolizers due to enhanced CYP2C19 enzyme activity clear omeprazole from their system faster than normal, reducing its effectiveness in suppressing stomach acid [2]. As a result, these individuals may require higher doses of the drug to achieve the same therapeutic effect as someone with normal metabolism [2].
Side Effects:
What Happens:
In poor metabolizers, the body processes drugs very slowly due to reduced or non-functional enzyme activity. This leads to prolonged presence of the drug in the system, resulting in higher concentrations than intended, which increases the risk of side effects and toxicity [4].
Example:
A well-known example is the interaction between the CYP2C19 gene and the drug clopidogrel (Plavix). Poor metabolizers with reduced or non-functional CYP2C19 enzyme activity cannot efficiently convert clopidogrel into its active form. As a result, the drug may not work effectively to prevent blood clots, leading to an increased risk of heart attack or stroke in individuals who rely on this medication [4].
Side Effects:
What Happens:
Normal Metabolizer processes drugs at the expected rate, allowing the medication to work effectively without causing unwanted side effects or drug buildup [13]. In simple terms, a normal metabolizer handles medications just right, not too fast or too slow [13].
Reporting test results within just 3-5 days.
Collecting samples from patients’ homes, offices, doctors’ clinics, hospitals, disability homes, and nursing homes at no charge.
Analyzing 18 genes involved in the metabolism of 116 medications, all for just $193.
Using swabs for sample collection ensures your comfort.
Partnering with Incite Genomics for sample analysis and report generation at their NATA-accredited lab (No. 20374).
Providing exceptional customer service with direct contact with the managing director, ensuring you receive timely and comprehensive support.
Refraining from outsourcing overseas services to ensure personal information remains secure, shared only with authorized medical professionals except where required by law.
Using top-tier equipment and assays, specifically the MassARRAY® System and high-quality primers and probes from Agena Bioscience—the technology used by leading providers in the industry.
1. Gaedigk A, Sangkuhl K, Whirl-Carrillo M, Klein TE, Leeder JS. Prediction of CYP2D6 phenotype from genotype across world populations. Genet Med. 2017 Feb;19(1):69-76.
2. Li XQ, Andersson TB, Ahlström M, Weidolf L. Comparison of inhibitory effects of the proton pump-inhibiting drugs omeprazole, esomeprazole, lansoprazole, pantoprazole, and rabeprazole on human cytochrome P450 activities. Drug Metab Dispos. 2004 Aug;32(8):821-7.
3. Crews KR, Gaedigk A, Dunnenberger HM, Leeder JS, Klein TE, Caudle KE, Haidar CE, Shen DD, Callaghan JT, Samwald M, Relling MV. Clinical Pharmacogenetics Implementation Consortium Guidelines for Cytochrome P450 2D6 Genotype and Codeine Therapy: 2014 Update. Clin Pharmacol Ther. 2014 Oct;95(4):376-82.
4. Scott SA, Sangkuhl K, Stein CM, Hulot JS, Mega JL, Roden DM, Klein TE, Altman RB. Clinical pharmacogenetics implementation consortium guidelines for CYP2C19 genotype and clopidogrel therapy: 2013 update. Clin Pharmacol Ther. 2013 Sep;94(3):317-23.
5. Maher, R.L., 2013. Challenges of polypharmacy in older adults. Aging Health, 9(1), pp. 1-4.
6. Soldin, O.P. and Mattison, D.R., 2009. Sex differences in pharmacokinetics and pharmacodynamics. Clinical Pharmacokinetics, 48(3), pp.143-157.
7. Tate, S.C., et al., 2015. Body weight and its effect on pharmacokinetics. British Journal of Clinical Pharmacology, 80(3), pp.401-409.
8. Mayo Clinic Staff, 2018. Cytochrome P450 tests. Mayo Clinic. Available at: <https://www.mayoclinic.org/tests-procedures/cyp450-tests/about/pac-20385041> [Accessed 6 September 2024].
9. Jones, A.L., 2012. Drug and alcohol interactions. Australian Prescriber, 35(1), pp.14-16.
10. NICE, 2020. Multimorbidity: Clinical assessment and management. NICE Guideline [NG56].
11. Patterson, R., et al., 2010. Drug allergy: Clinical aspects and diagnosis. Journal of Allergy and Clinical Immunology, 125(3), pp.572-580.
12. Hansten, P.D. and Horn, J.R., 2008. Drug interactions: Analysis and management. Wolters Kluwer Health.
13. Klein, T.E., and Altman, R.B., (2004). Pharmacogenetics and pharmacogenomics. Pharmacogenetics, 4(1), 1-15. doi:10.1097/01.fpc.0000128922.04313.2e.
