Case example:
Dan is a 49-year-old male with a past medical history significant for hypertension, dyslipidemia, and lower back pain secondary to a recently herniated disc. He reports today that he has been using the maximum dosage of his tramadol prescription and not gaining any relief. His hypertension and dyslipidemia are currently well controlled by medication therapy.
Current Medications
- Losartan 100 mg daily
- Rosuvastatin 20 mg daily
- Tramadol 50 mg every 4-6 hours as needed daily
Background:
Dan reported to the emergency room 4 days ago after experiencing sharp pain in his back while lifting a bag of soil in his backyard 2 days before. He reported back and hip pain at a level of 7/10. He was diagnosed with a herniated lumbar disc post-MRI and was given tramadol as needed for his pain along with a referral for physical therapy.
Today, Dan reports to his PCP that the pain has progressively worsened over the past 3 days after initially having some benefit. He reports the lower back and hip pain at a level of 7/10. He requests a new medication to help ease the pain.
Dan has PGx test results available as he recently had an opportunity to receive pharmacogenomic testing through his employer’s new benefits package. Dan and his PCP agreed to look at the PGx test results to see if there was anything there that could help him out with selecting a pain medication.
Results
| Gene/Genotype | Phenotype | Implications |
| CYP2D6 *1/*4 | Intermediate Metabolizer | Reduced tramadol exposure as compared to normal which may result in lack of efficacy. |
| CYP2C9 *1/*1 | Normal Metabolizer | Normal NSAID exposure expected. |
The results reveal that Dan is an intermediate metabolizer at CYP2D6. The implication is reduced tramadol exposure and increased risk for lack of efficacy. Dan is also a normal metabolizer at CYP2C9. CYP2C9 is associated with NSAIDs (nonsteroidal anti-inflammatory drugs), and the normal metabolizer phenotype implicates normal exposure to NSAIDs.
Considerations
After reviewing the test results, Dan and his PCP discussed the significance of the CYP2D6 and CYP2C9 genotypes as it relates to pain medication selection. His PCP investigated the available guidelines and literature and found the Clinical Pharmacogenetics Implementation Consortium (CPIC) guidelines for CYP2D6 and opioid therapy as well as CYP2C9 and NSAID therapy. These guidelines recommend switching from tramadol if ineffective in CYP2D6 intermediate metabolizers and using standard dosing for NSAIDs in CYP2C9 normal metabolizers. After considering Dan’s other clinical factors and concluding this medication change was safe, his PCP switched from tramadol to ibuprofen 400 mg every 4-6 hours as needed.
Conclusion
After consulting the PGx test results, they were able to make an informed decision for the medication switch, leading to improvements in Dan’s pain relief. Dan’s PGx results will continue to provide valuable insights for future medication decisions. This case highlights how pharmacogenomics can facilitate more tailored and effective treatment plans to improve patient outcomes and safety.
Victor Tam, PharmD is a PGx certified clinical pharmacist and is currently a Senior Medical Science Liaison at OneOme LLC, a med tech company located in Minneapolis, MN. OneOme offers additional information and PGx education which can be found at OneOme.com/education.
