Unlocking Pain Relief: The Role of Pharmacogenomics in Optimizing Opioid Therapy

One of the reasons patients may overuse opioids for pain management is because the medicine is not providing benefit, leading to increased use of the medicine to experience relief, explained Jacqueline H. Cleary, PharmD, BCACP, during a presentation at the 2024 American College of Clinical Pharmacy (ACCP) Annual Meeting. In this situation, patients with chronic pain may feel disheartened. According to Cleary, associate professor and director of the pharmacogenomic certificate program at Albany College of Pharmacy and Health Sciences (ACPHS), pharmacogenomic testing may prove highly valuable for these patients.

Patients with chronic pain may feel disheartened if their pain medicine is not providing benefit. Image Credit: © Stocks Buddy - stock.adobe.com

“I have so many patients that have never been tested before. They've tried all these pain medicines that have failed. When they do the test, it's like this sigh of relief because they're like, ‘Oh yeah, I am a poor CYP2D6 metabolizer. Oh yeah, my miR-182 is inducible, and I smoke,’” Cleary said during the ACCP session. “It's almost a sense of relief. It would be a really interesting study to see if just testing in general leads to a better patient response, because they have a lot more information. They feel more empowered with knowing, ‘It's not all in my head. I'm not crazy. There are just certain drugs I don't respond as well to.’”

Additionally, many patients are now seeing advertisements for pharmacogenomic testing, according to Cleary. This has increased general patient interest in pursuing testing and seeking consults for more information about them.

“I will say, in this past year, the majority of consults for some type of genotyping I receive are coming from primary care patients who are hearing commercials on the news. I saw a commercial for one [pharmacogenomic test] during a football game the other day, so patients are interested in this,” Cleary said. “A lot of the requests for doing this testing is someone that's had chronic pain, has failed a lot of therapies, and this is an option to potentially turn to for better results.”

Depending on a patient’s genotype, certain drugs can cause adverse effects or be less effective, making a genetic test very valuable. For opioids in particular, this type of drug information can be critical.

“We test to make sure the drug is safe and that the drug is actually going to work,” Cleary said.

However, Cleary noted that guidelines from Clinical Pharmacogenetics Implementation Consortium (CPIC) and Dutch Pharmacogenetics Working Group (DPWG) have a strong recommendation to not change a therapy based on pharmacogenomic testing results without consulting a physician.

“So don't get this report in your email and see that your medicine is in the red column of the report and then just stop the medicine altogether,” Cleary said.

Cleary explained further that the reports are often organized into 2 different types: pharmacodynamic and pharmacokinetic genes.

“The kinetic genes are the ones I think most of us are most comfortable with,” Cleary said. “Then there's the pharmacodynamic genes that are a little bit more elusive, I think, to some folks. Also, the body of evidence supporting making therapeutic changes around pharmacodynamic genes is much, much less.”

Additionally, Cleary noted that when using pharmacogenomic information to change a patient's therapeutic regimen, there is not solely one aspect of the study that informs recommendations for a change.

“I'm looking at kinetics, I'm looking at side effects, I'm looking at cost,” Cleary said. “This is only a small percentage of the overall pie where we go into a discussion about doing genetics, and again, in the consenting process up front, I tell the patient that just because we're doing this test does not mean your drug therapy might change. So, this is just one piece of the pie.”

Cleary noted that she starts discussions around consent during the initial consult.

“When we bring the patient in for a consult to do a pharmacogenomic test, we go through the full consent with them. When the results come back, we do a consult note, and then we bring them in again to go over that entire, really confusing report,” Cleary said. “It's really important, especially in this space, to make sure the patient has clarity. They need to understand why you're testing and understand what the test can do for them.”

During conversations around consent, Cleary noted that it can also be important to talk to them about what's going to happen to their information, especially if they have family members who have also been tested. Specifically, challenges can arise if other family members have had genetic testing done and the patient learns they are not a genetic match.

“We have run into some paternity concerns, believe it or not,” Cleary said. “A patient gets a test done because a lot of the especially psychiatric or chronic pain conditions run in the family. Another family member gets the test done and they don't match, and that can open the door for a lot of perhaps difficult conversations. So consenting is so important, so that they understand what this information is, how it's going to be used, and who's going to have access to it.”

Another challenge with genetic testing results is finding a place to store that information. Cleary explained that she has found that it can be difficult to store testing information in the electronic medical record (EMR) at her health system, ACPHS. Within CPIC, there is a working group that is looking into solutions to automating testing results within EMRs so that health care professionals can quickly identify whether a patient has already been tested, but this has not been widely adopted in health systems as of yet.

“Right now, in my EMR, nobody knows patients had pharmacogenetic testing unless they know to go and look for it. And I think that's the majority of us,” Cleary said. “A lot of these companies actually can integrate with EMRs. If you're using a specific test now, I would reach out to a medical science liaison or to your rep and ask them about whether their test can integrate with some of the bigger EMRs, like EPIC or Cerner.”

Through integration with the EMR, pharmacogenetic testing results can be accessed throughout the health care system, Cleary explained. This can allow health care professionals of different specialties to appropriately apply that information during patient care and treatment decisions. However, Cleary also noted that it is essential to check CPIC, DPWG, and FDA guidelines and information as pharmacogenomic testing information is constantly being updated, meaning the guidelines can change quickly. However, this can be an area where the pharmacist can excel and find a lot of benefit.

“Pharmacogenomics can be a really valuable tool to a pain pharmacist. There's a lot of different applications for kinetics and dynamics for specific drugs,” Cleary said. “You have to consider cost, accessibility, interpretation, and how you're going to incorporate this into your workflow, as well as consenting the patient and making sure they have the best information. But overall…it's a really exciting and dynamic field.”

REFERENCE

Cleary JH. Pharmacokinetics/Pharmacodynamics/Pharmacogenomics and Pain and Palliative Care PRN Focus Session — Personalized Pain Management: Evaluating the Clinical Utility and Application of Pharmacogenetics. Presented at: 2024 American College of Clinical Pharmacy Annual Meeting; October 12-15, 2024; Phoenix, Arizona.