Emerging pharmacogenetic testing could be big boon for early adopters

RENO, Nev. — Pharmacogenetic testing represents a new tool for pharmacists that has the potential to optimize the specific medicines their patients are taking, identify the best dose of that medicine for the individual patient and also create a record of those optimized medicines and dosing recommendations for hundreds of medicines that can be kept on file for future reference. 

 

"Just like drug-drug interaction and drug-allergy interaction, this is drug-gene interaction," Chuck Dushman, VP sales MD Labs, said. "The pharmacies that lock up these patients first are going to have an advantage."

 

This kind of emerging technology has the potential to transform how medicines are prescribed and filled, Dushman added. 

 

For example, the liver enzyme known as CYP2D6 acts on a quarter of all prescription drugs, including the painkiller codeine, which it converts into the drug’s active form, morphine. The CYP2D6 gene exists in more than 160 different versions, many of which vary by only a single difference in their DNA sequence, although some have larger changes. 

 

The majority of these variants don’t affect drug responses.

 

Some people have hundreds or even thousands of copies of the CYP2D6 gene (typically, people have two copies of each gene). Those with extra copies of this gene manufacture an overabundance of CYP2D6 enzyme molecules and metabolize the drug very rapidly. As a result, codeine may be converted to morphine so quickly and completely that a standard dose of the drug can be an overdose.

 

On the other end of the spectrum, some variants of CYP2D6 result in a nonfunctional enzyme. People with these variants metabolize codeine slowly, if at all, so they might not experience much pain relief. For these people, doctors might prescribe a different type of pain reliever. 

 

One major study cited by American Nurse Today found incorrect dosing accounted for 42% of adverse reactions while genetic factors caused approximately 50%. 

 

According to a study published in the Clinical Trends in Molecular Medicine, there is a significant segment of the population for which a particular drug is ineffective. For example, 38% of prescribed antidepressants are deemed ineffective. The percentage of other populations for which particular drugs are ineffective include: 

 

To date, MD Labs' RxIGHT is the most comprehensive pharmacogenetic test available, covering more than 200 medications across 14 therapeutic categories. And that's not a static number - more manufacturers are expected to conduct pharmacogenetic tests for their prescription products going forward. 

 

One of the advantages associated with the RxIGHT Pharmacogenetic Test is the patient's genetic profile is measured against the full battery of medications. So the test, taken once, can help optimize future prescriptions. 

 

MD Labs' RxIGHT Pharmacogenetic Test puts the pharmacist front and center in pharmacogenetics, helping elevate their role as clinical advisor to their patient and their physician partners. The MD Labs program utlizes a Personalized Medication Review as the mechanism for helping the patient understand the implication of the RxIGHT test results on not ony their current medication needs, but also how the RxIGHT test can help optimize future pharamceutical therapies. 

 

"It is just eye-opening for these patients as to the impact their genetic profile has on their current medications," Dushman said. "And now that pharmacy has the genetic profile and the implications for future medications. So when [the patient] has another medication need, why would they go anywhere else?"