Q was to have a cavity filled and it hit me just when I woke that I never told the dentist about his CYP450 2d6 and 2c19 poor metabolizer issues.... So I called the dentist and he said we had to cancel and he had to do some research because he doesn' want him in pain...it could be nothing or it may mean we need another plan... BUT, I have to research this of course, LOL and I remember some here wondering if they had CYP enzyme issues because they or their difficult child had weird medication. issues. Almost 25% of all drugs on the market today are broken down by a specific enzyme within the Cytochrome P450 class of enzymes known as CYP 2D6. This is well known by chemical scientists. What is less known, and what big pharma has tried to keep under wraps is that not everyone has this enzyme, and for those that do - there may be subtle variations or "defects" in their genetic makeup so that not everyone produces the same amount of this enzyme. This science is so well understood that the population has been divided into four main categories, and they are: 1. Ultra extensive metabolizers 2. Extensive metabolizers 3. Intermediate metabolizer 4. Poor metabolizer Now let me provide you with a couple of examples to help you better understand why this information is so important. Let's say that someone is an ultra extensive metabolizer of Novocaine. This means that this person produces an "excess" amount of the enzyme that breaks down Novocaine and helps to clear this chemical from the person's body. So, when this person goes to the dentist to have some work done, the dentist administers the standard dose of Novocaine, and believing that his patient is now numb, begins to work. The patient screams out in pain because the standard dose of Novocaine had no effect. The patient's enzymes broke down the Novocaine quickly, before the drug could produce its intended effect. Now, lets say that Prozac is prescribed for a poor metabolizer. This patient has a genetic variant which results in very little production of CYP 2D6. Not only that, but the patient has also been taking another drug which needs CYP 2D6 enzyme for break down and clearance. Because the enzyme which breaks down Prozac is deficient, levels of the drug soon build to toxic levels.