Why Do People
React Differently to the Same Psychiatric Drug Dosages?
Posted on Yahoo!
Groups by Cassandra Casey (israelswarrior@hotmail.com)
on January 2, 2007
The answer lies in the field
of pharmacogenomics. Basically, what this
means is that we all have different response variations to different
chemicals. Just as one person can be helped by penicillin, penicillin can
be fatal to others. This science is well understood by all drug companies,
and if you will do a search through the PubMed files, you will find many
studies that have been paid for by big pharma to better understand these
variables.
You've probably argued with some people who will look you straight in the
eye and tell you that "Prozac saved their life", and yet another person
became actively suicidal on the same drug.
While I will never advocate using any type of psychiatric drug, I am also
very cautious of using ANY drug, even if the safety record has been "well
established". However, I will admit that from what I have studied Prozac
will not induce suicidal ideation or homicidal rage in everyone who uses it.
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.
I have already listed for you several of the studies which I found several
years ago within the PubMed files on this topic. They are all contained
within a file that has been downloaded and can be found in the "files"
section of this board.
If you would like to know more, do a search for "pharmacogenomics". Also,
this is one of the best reputable websites that explains this in more detail
in language that anyone can understand if they will take time to read
through it:
http://www.healthanddna.com/adversedrugreactions.html
Here are a few more links:
Scientific American: In Focus: Personal Pills: October 1998 at
http://www.sciam.com/1998/1098issue/1098infocus.html
Genetic Testing Checks For Drug Reactions
http://komotv.com/healthwatch/story.asp?ID=10875
Cytochrome P450 enzymes: Introduction (Psychotropical Research) at
http://www.psychotropical.com/notes/316.html
"There is great genetic variation in the activity level of most cytochrome
P450 enzymes both between persons (and genetic groups)." and "The incidence
of serious and fatal adverse drug reactions is high in hospital patients.
This causes an estimated 100,000 deaths per year in the US, making it the
5th most frequent cause of death. Genotyping for cytochrome P450 enzymes may
avoid as many as 20% of these deaths."
Enzyme key to reaction, scientists say By Andrew Wineke, Everett Herald,
Tuesday, August 4, 1998, p C1 & C2
http://wsmcsn.s5.com/Enzyme.htm
Chemical Sensitivity Due to Genetic Differences at
http://ace.orst.edu/info/extoxnet/faqs/senspop/genetic.htm
I have quite a bit of information on this subject, but these links will
provide you with a basic understanding. Happy reading!
Best to all,
Cassie
Cassandra Dawn Casey
If you’re not outraged, you’re not paying attention.
http://www.scientific-misconduct.blogspot.com
Utah Director, ICFDA
DRUGAWARENESS
http://www.drugawareness.org
A.S.P.I.R.E.
http://www.aspire.us
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