"Some Web sites make explicit claims about the utility of CYP450 testingfor particular drugs, such as the claim by Genelex that pharmacogenetictesting is "required to effectively prescribe Paxil"(http://www.healthanddna.com/professional/paxil.html).
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The actual statement is:
Paxil (paroxetine) is metabolized through CYP2D6. Pharmacogenetic testingof this pathway serves as an anchor for the intense personalization requiredto effectively prescribe Paxil and other antidepressant medicines.
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Randomized trials are in progress that will add to our knowledge. In themeantime clinicians and patients who find this information useful should haveaccess to it. Physicians don't prescribe without knowing the patient's age,sex, and medical history, and often CYP genetics are more important than allthese factors combined.Facts and quotes: -- "The cytochrome P-450 test represents a major advance in the ability to provide the best care possible for depression." http://www.mayoclinic.org/depression/cytochrome.html. -- Hospitalized psychiatric patients who are poor metabolizers cost $4,000 - $6,000 more in medical care compared to patients with an average metabolizer genotype. Virtually, all antidepressants and antipsychotic medicines are processed by enzymes with a high incidence of poor metabolizers. Journal of Clinical Psycopharmacology 20:246 2000. -- Fifty-nine percent of drugs most commonly cited in ADR studies are processed by enzymes with genes known to have poor metabolizer variants. This is compared to 7% of a random selection of the top selling drugs. (JAMA 286:2270 2001). -- Multiple studies have found that people with CYP variants require lower doses of the affected medications. Molecular Psychiatry 9:442-473, 2004. -- "Putting what we know into practice would prevent more disease than worshiping at the altar of randomized trials." John Concato, MD, Yale University. Genelex's Position: -- Individuals have a right to learn their genotype and control who accesses this confidential information. -- Excessive regulation will impede the already slow adoption of DNA testing in medication management. -- There needs to be symmetry between the level of proof required for technology adoption and the potential risk and cost benefit ratios. -- A peer-developed rating system needs to be developed that describes where a given test lies on the continuum of scientific knowledge about the utility, acceptance and proof of that test as a tool for informed decision-making.
SOURCE Genelex Corporation
