The Role of the Pharmacist in Pharmacogenetics

The top 5 causes of emergency hospitalizations due to adverse drug events are warfarin, insulin, oral antiplatelets, diabetes medications, and opioid pain medications.1 With the exception of insulin, science has shown how genetic implications in an individual’s metabolism influence the safety and efficacy of all of these medications. How many of the millions of adverse drug reactions and hospitalizations could be prevented if patients were consistently put on the right drug and the right dose based on their genetic makeup, and, importantly, avoided medications that were ineffective or put them at increased risk of an adverse drug event? As medication treatment becomes more proactive and personalized, pharmacists have a unique opportunity to play a vital role on the health care team through clinical application of pharmacogenetic information in patient care.

Pharmacogenetic testing is more than getting a cheek swabbed and seeing the results. Once patients know they are CYP2D6 ultrarapid metabolizers, what is next? Well, like normal individuals, they go to “Dr. Google.” What if, based on their Internet search, they discontinue all their medications that are affected by CYP2D6? Also, remember that pharmacogenetics is just one piece of the puzzle.

There are drug-drug interactions, liver and kidney function, and environmental factors to consider, as well. What if these patients were on a medication that inhibited CYP2D6? What would be the appropriate course of action then? This is called phenoconversion, which is when an individual’s genotypic phenotype differs from his or her observed phenotype due to nongenetic extrinsic factors, such as drug-drug interactions.2

For precision medicine, pharmacists need to consider drug-drug-gene interactions, as well. These are the questions and concerns that arise when the medical community is asked about how pharmacogenetic information could be safely and ethically delivered to the community. Pharmacists have always been the medication experts dealing with drug-drug interactions on a daily basis. Now, with the new tool of pharmacogenetics, we can become the drug-druggene experts, as well.

As a profession, we have a responsibility to our patients to always be at the forefront of education and knowledge about medications and how they work in the body. As the most accessible (first-line) health care providers in our communities, pharmacists must have a solid understanding of this complex science in order to use the right language with patients and to clarify misconceptions and avoid misuse of this information. Most important, pharmacists should ensure coordination of care with patients’ medical providers to ensure that this information does not go to waste. By showing patients the potential impact of their genetic profile, pharmacists will truly have an impact on the lives of their patients and reduce avoidable health care costs.

Pharmacists can serve as a pharmacogenetic resource for medical providers. As most medical clinics may be short on clinical staff and have limited genetic counselors, pharmacists can become a tremendous resource and support for medical providers.

Pharmacists are ideal for disseminating pharmacogenetic information to patients who see multiple medical providers and specialists. Because all patients are encouraged to use 1 pharmacy, it can become the ideal center for housing patients’ pharmacogenetic information. Pharmacists are already intervening in drug-drug interactions from multiple providers; therefore, it seems fitting that pharmacists intervene when patients are placed on new medications with a pharmacogenetic implication, while also taking into account other inducers and inhibitors on patients’ profiles.

“Retailer” stigma is one of the challenges that the pharmacy profession faces when stepping into pharmacogenetics or any clinical role. The general public and, sometimes, the medical community may only see a pharmacist as someone behind a counter whose sole purpose is to put medications into bottles. We know the truth, but what are we doing in our daily practice to reveal it to our patients and other health care professionals? A grassroots movement does not start with Congress or legislation. It starts with each of us in our daily practice.

In the model we propose for best practices for the safe and ethical delivery of pharmacogenetic information, the prescriber is engaged from the outset, patients are counseled on their results by a pharmacist trained in pharmacogenetics, and pertinent findings are coordinated with patients’ medical providers. Pharmacy-dispensing software systems and electronic health records have started integrating patients’ pharmacogenetic information to alert a pharmacist or a medical provider with clinical decision support.

It is vitally important that pharmacists get involved in the field of pharmacogenetics. Direct-to-consumer pharmacogenetic testing has been stopped by the FDA, as this kind of testing puts patients at risk. The more we can avoid patient dependence on “Dr. Google” for answers to health care questions, the better. Pharmacists’ knowledge and accessibility to medical providers and to communities will bring value to precision medicine. The roles of pharmacists in all settings are shifting. As our profession takes on more clinical roles, we have a responsibility to our patients and to medical providers in our communities to be a knowledgeable and reliable medication resource, which increasingly includes pharmacogenetics.

REFERENCES

  1. Budnitz DS, Lovegrove MC, Shehab N, Richards CL. Emergency hospitalizations for adverse drug events in older Americans. N Engl J Med. 2011;365(21):2002-2012. doi: 10.1056/NEJMsa1103053.
  2. Shah RR, Smith RL. Addressing phenoconversion: the Achilles’ heel of personalized medicine. Br J Clin Pharmacol. 2015;79(2):222-240. doi:10.1111/bcp.12441.

Source: Pharmacy Times

Author:

Amina Abubakar, PharmD, AAHIVP, and Olivia Bentley, PharmD, AAHIVP, CFTS

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