A consortium called CPIC has issued a new guideline on genetic tests that can mean the difference between toxic reactions or unrelieved pain for some patients on codeine. Dr. Mary Relling tells why primary care doctors need good information right now about the links between genes and drug response, and where you can find it.
Suddenly, genetic testing is entering the realm of primary care. About 10% of FDA approved drugs now mention genetic tests on their labels, relating to genes known to control how the drug is metabolized. Once the province of medical geneticists, pharmacogenomics is beoming a must-know topic for family doctors as well.
Here to help is a new gene testing registry launched by the NIH and, behind much of the information there, the actions of the independent Clinical Pharmacogenetics Implementation Consortium (CPIC), which issues guidelines about the use of gene tests to improve drug response. Here to discuss CPIC, its guidelines, and the latest release on codeine and the gene called CYP2D6.
Dr Relling is chair of the pharmaceutical department at St. Jude Childrens Research Hospital in Memphis, and a founder of CPIC.
"We have to avoid codeine and tramadol in ultarapid metabolizers and those 10% of the population that is poor metabolizers don't get any benefit at all."
"Much of this information has actually been known for 20 or 30 years. One of the reasons that we have been held back is that testing hasn't been as widely or inexpensively available as it is now."
1. What is CPIC?
2. Who is behind CPIC? Who are the members?
3. Which guidelines have been issued so far?
4. Why was the new codeine guideline necessary and what does it provide?
5. How widely available are the genetic tests that underlie pharmacogenomics?
6. How likely is it that a patient's insurance will pay for these tests?
7. What are the odds that a primary care doctor will need to know about this in the near future?
New Codeine Guideline and More Help With Pharmacogenomics
The Pharmacogenomics Knowledge BaseA project involving CPIC and the Pharmacogenomics Research Network
HLA-B Genotype and Abacavir DosingClinical Pharmacology and Therapeutics, April 2012
Codeine Therapy in the Context of Cytochrome P450 2D6 (CYP2D6) GenotypeClinical Pharmacology and Therapeutics, February 2012
CYP2C9 and VKORC1 genotypes and warfarin dosingClinical Pharmacology and Therapeutics, October 2011
Cytochrome P450-2C19 (CYP2C19) Genotype and Clopidogrel TherapyClinical Pharmacology and Therapeutics, August 2011
Thiopurine Methyltransferase Genotype and Thiopurine DosingClinical Pharmacology and Therapeutics, December 2010