Brandon Turbervile comprehensive article: Psychiatric Drugs, School Violence, and the Big Pharma Cover-up
the CYP450 enzymes are the primary catalysts for detoxification reactions that render water-insoluble molecules sufficiently water soluble to be excreted in the urine. . . . Drugs, hormones, toxins, carcinogens, mutagens, environmental pollutants, and other xenobiotics are metabolized by CYP450 enzymes.
Of the CYP450 enzyme family, there are other more specific enzymes such as CYP2C9, CYP2C19, and CYP2D6, etc. These three enzymes specifically are responsible for approximately 40% of all CYP450-mediated drug metabolism. The CYP2D6 enzyme itself is responsible for the bulk of drug metabolism at around 20% to 30% of drug metabolism in the CYP450 family.
In relation to the CYP2D6 enzyme, there are four classifications – Extensive Metabolizers (EM), Poor Metabolizers (PM), Intermediate Metabolizers (IM), and Ultrarapid Metabolizers (UM).EM (Extensive Metabolizers) are considered the “normal genotype,” “which is free of inactivating polymorphisms, deletions, or duplications.” PM (Poor Metabolizers) are individuals who have “deficient” enzyme function in terms of CYP450 metabolic processes and, subsequently, have difficulty clearing certain medications. IM (Intermediate Metabolizers) are those who have some functioning CYP450 enzymes but are subject to loss of the function of these enzymes after the “second hit” of medication, thus turning them into PM. UM (Ultrarapid Metabolizers) are those who metabolize the drug so rapidly that it clears so quickly that there is little or none of the desired effect. In medications that required metabolism to activate, however, UM individuals the metabolite may be produced too quickly, resulting in toxicity and the realization of side effects.While there are potentially adverse health effects with any one of the four classifications, the focus of this article is on those who are generally PM (Poor Metabolizers). This is because these individuals have a higher chance of experiencing adverse health effects of pharmaceuticals than those with “normal” functioning EMCYP2D6 enzymes.