{"id":69087,"date":"2026-02-23T14:50:55","date_gmt":"2026-02-23T13:50:55","guid":{"rendered":"https:\/\/www.easly.nl\/biomarkers\/cyp2d6\/"},"modified":"2026-02-23T14:51:42","modified_gmt":"2026-02-23T13:51:42","slug":"cyp2d6","status":"publish","type":"biomarkers","link":"https:\/\/www.easly.nl\/en\/biomarkers\/cyp2d6\/","title":{"rendered":"CYP2D6"},"content":{"rendered":"<h2>What is CYP2D6?<\/h2>\n<p>CYP2D6 is a crucial enzyme in the liver responsible for the breakdown and activation of approximately <strong>25% of all medications<\/strong> prescribed worldwide. Unlike biomarkers like GGT, which can fluctuate, your CYP2D6 status is genetically determined and unchangeable.<\/p>\n<p>The gene determines whether you metabolize medications &#8220;normally,&#8221; or whether this process is far too slow or too fast. This directly impacts the effectiveness of your treatment and the risk of side effects.<\/p>\n<h2>Why test your CYP2D6 status?<\/h2>\n<p>When the CYP2D6 enzyme activity is abnormal, the standard dosage of a medication may be unsafe or ineffective for you:<\/p>\n<ul>\n<li><strong>Side effects:<\/strong> If the medication is broken down too slowly, it accumulates in your blood, which can lead to serious side effects, even at a &#8220;normal&#8221; dose.<\/li>\n<li><strong>No effect:<\/strong> If the medication is broken down too quickly, it is removed from your body before it can do its job.<\/li>\n<li><strong>Inactive medication:<\/strong> Some medications (such as codeine) require activation by CYP2D6. If the enzyme isn&#8217;t working, you won&#8217;t experience any pain relief.<\/li>\n<\/ul>\n<h2>Medicines in which CYP2D6 plays a role<\/h2>\n<p>The following groups of medications are primarily metabolized by the CYP2D6 enzyme. An Easly pharmacogenetic passport is very valuable for these medications:<\/p>\n<ul>\n<li><strong>Antidepressants:<\/strong> e.g., Amitriptyline, Venlafaxine, Paroxetine, Fluoxetine.<\/li>\n<li><strong>Beta-blockers:<\/strong> e.g., Metoprolol, Bisoprolol.<\/li>\n<li><strong>Painkillers:<\/strong> e.g., Tramadol, Codeine.<\/li>\n<li><strong>Antipsychotics:<\/strong> e.g., Haloperidol, Risperidone.<br \/>\nOncology: Tamoxifen.<\/li>\n<\/ul>\n<h2>Interpretation of your CYP2D6 status<\/h2>\n<p>Your genetic test results are classified into four metabolism types. This determines how your body responds to the medications mentioned above:<\/p>\n\n<table id=\"tablepress-191\" class=\"tablepress tablepress-id-191 biomarker-table\">\n<thead>\n<tr class=\"row-1\">\n\t<th class=\"column-1\">Result<\/th><th class=\"column-2\">Interpretation<\/th><th class=\"column-3\">Impact on Medication<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr class=\"row-2\">\n\t<td class=\"column-1\">PM<\/td><td class=\"column-2\">Poor Metabolizer<\/td><td class=\"column-3\">The enzyme doesn't work. High risk of side effects or no effect with prodrugs (such as codeine).<\/td>\n<\/tr>\n<tr class=\"row-3\">\n\t<td class=\"column-1\">IM<\/td><td class=\"column-2\">Intermediate Metabolizer<\/td><td class=\"column-3\">The enzyme works slowly. Increased risk of side effects; a lower dosage is often desirable.<\/td>\n<\/tr>\n<tr class=\"row-4\">\n\t<td class=\"column-1\">NM<\/td><td class=\"column-2\">Normal Metabolizer<\/td><td class=\"column-3\">The enzyme is functioning normally. The standard dosage is usually appropriate for your body.<\/td>\n<\/tr>\n<tr class=\"row-5\">\n\t<td class=\"column-1\">UM<\/td><td class=\"column-2\">Ultrarapid Metabolizer<\/td><td class=\"column-3\">The enzyme works extremely quickly. Medication is broken down too quickly; standard doses are often ineffective.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<!-- #tablepress-191 from cache -->\n<h2>Medical interpretation &amp; advice<\/h2>\n<p>The results of your test at Easly are checked against the official <strong>KNMP medication guidelines (G-Standard)<\/strong>. This provides you, your pharmacist, and your doctor with a scientific foundation for personalized treatment.<\/p>\n<p><strong>Important: Always use this result in consultation with your doctor or pharmacist. Never adjust your dosage independently.<\/strong> A doctor or pharmacist may decide to optimize your dosage or switch to a medication that is not dependent on this specific enzyme based on your profile.<\/p>\n<p>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<a href=\"https:\/\/www.easly.nl\/en\/dna-passport-for-medication\/\"><br \/>\n\t\t\t\t\t\t\t<img fetchpriority=\"high\" decoding=\"async\" width=\"1260\" height=\"460\" src=\"https:\/\/www.easly.nl\/wp-content\/uploads\/sites\/13\/2026\/02\/Farmaco-biomarker-banner-1.png\" alt=\"Farmaco biomarker banner\" srcset=\"https:\/\/www.easly.nl\/wp-content\/uploads\/sites\/13\/2026\/02\/Farmaco-biomarker-banner-1.png 1260w, https:\/\/www.easly.nl\/wp-content\/uploads\/sites\/13\/2026\/02\/Farmaco-biomarker-banner-1-300x110.png 300w, https:\/\/www.easly.nl\/wp-content\/uploads\/sites\/13\/2026\/02\/Farmaco-biomarker-banner-1-1024x374.png 1024w, https:\/\/www.easly.nl\/wp-content\/uploads\/sites\/13\/2026\/02\/Farmaco-biomarker-banner-1-768x280.png 768w, https:\/\/www.easly.nl\/wp-content\/uploads\/sites\/13\/2026\/02\/Farmaco-biomarker-banner-1-804x294.png 804w, https:\/\/www.easly.nl\/wp-content\/uploads\/sites\/13\/2026\/02\/Farmaco-biomarker-banner-1-1044x381.png 1044w\" sizes=\"(max-width: 1260px) 100vw, 1260px\" \/>\t\t\t\t\t\t\t\t<\/a><\/p>\n<p><strong>Don&#8217;t suffer through unexplained side effect<\/strong>s.<\/p>\n<p>Want to know if your symptoms can be explained by your DNA profile? Take the free <a href=\"https:\/\/www.easly.nl\/en\/dna-paspoort-test-online\/\">Pharmacogenetic Quick Scan<\/a> and get immediate confirmation of whether testing is beneficial for you.<\/p>\n<p>\t\t\t\t\t<a href=\"https:\/\/www.easly.nl\/en\/dna-paspoort-test-online\/\"><br \/>\n\t\t\t\t\t\t\t\t\tStart the Quick Scan<br \/>\n\t\t\t\t\t<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>The CYP2D6 test reveals how your DNA determines the effectiveness and side effects of 25% of all medications, so you can work with your doctor to tailor the dosage precisely to your unique metabolism.<\/p>\n","protected":false},"template":"","biomarkers_category":[2233],"class_list":["post-69087","biomarkers","type-biomarkers","status-publish","hentry","biomarkers_category-pharmacogenetics"],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v24.3 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>CYP2D6 - Easly Shop<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.easly.nl\/en\/biomarkers\/cyp2d6\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"CYP2D6 - Easly Shop\" \/>\n<meta property=\"og:description\" content=\"The CYP2D6 test reveals how your DNA determines the effectiveness and side effects of 25% of all medications, so you can work with your doctor to tailor the dosage precisely to your unique metabolism.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.easly.nl\/en\/biomarkers\/cyp2d6\/\" \/>\n<meta property=\"og:site_name\" content=\"Easly Shop\" \/>\n<meta property=\"article:modified_time\" content=\"2026-02-23T13:51:42+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/www.easly.nl\/wp-content\/uploads\/sites\/13\/2026\/02\/Farmaco-biomarker-banner-1.png\" \/>\n\t<meta property=\"og:image:width\" content=\"1260\" \/>\n\t<meta property=\"og:image:height\" content=\"460\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/png\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data1\" content=\"2 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\/\/www.easly.nl\/en\/biomarkers\/cyp2d6\/\",\"url\":\"https:\/\/www.easly.nl\/en\/biomarkers\/cyp2d6\/\",\"name\":\"CYP2D6 - Easly Shop\",\"isPartOf\":{\"@id\":\"https:\/\/www.easly.nl\/en\/#website\"},\"primaryImageOfPage\":{\"@id\":\"https:\/\/www.easly.nl\/en\/biomarkers\/cyp2d6\/#primaryimage\"},\"image\":{\"@id\":\"https:\/\/www.easly.nl\/en\/biomarkers\/cyp2d6\/#primaryimage\"},\"thumbnailUrl\":\"https:\/\/www.easly.nl\/wp-content\/uploads\/sites\/13\/2026\/02\/Farmaco-biomarker-banner-1.png\",\"datePublished\":\"2026-02-23T13:50:55+00:00\",\"dateModified\":\"2026-02-23T13:51:42+00:00\",\"breadcrumb\":{\"@id\":\"https:\/\/www.easly.nl\/en\/biomarkers\/cyp2d6\/#breadcrumb\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/www.easly.nl\/en\/biomarkers\/cyp2d6\/\"]}]},{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\/\/www.easly.nl\/en\/biomarkers\/cyp2d6\/#primaryimage\",\"url\":\"https:\/\/www.easly.nl\/wp-content\/uploads\/sites\/13\/2026\/02\/Farmaco-biomarker-banner-1.png\",\"contentUrl\":\"https:\/\/www.easly.nl\/wp-content\/uploads\/sites\/13\/2026\/02\/Farmaco-biomarker-banner-1.png\"},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\/\/www.easly.nl\/en\/biomarkers\/cyp2d6\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\/\/www.easly.nl\/en\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Biomarkers\",\"item\":\"https:\/\/www.easly.nl\/en\/biomarkers\/\"},{\"@type\":\"ListItem\",\"position\":3,\"name\":\"CYP2D6\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\/\/www.easly.nl\/en\/#website\",\"url\":\"https:\/\/www.easly.nl\/en\/\",\"name\":\"Easly Shop\",\"description\":\"Safe &amp; 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