Savvy Psychopharmacology

Pharmacogenomics testing: What the FDA says

Current Psychiatry. 2019 April;18(4):29-33

References

1. Bousman CA, Arandjelovic K, Mancuso SG, et al. Pharmacogenetic tests and depressive symptom remission: a meta-analysis of randomized controlled trials. Pharmacogenomics. 2019;20(1):37-47.
2. Zubenko GS, Sommer BR, Cohen BM. Pharmacogenetics in psychiatry: a companion, rather than competitor, to protocol-based care-reply. JAMA Psychiatry. 2018;75(10):1090-1091.
3. International Society for Psychiatric Genetics. Genetic testing statement: genetic testing and psychiatric disorders: a statement from the International Society of Psychiatric Genetics. https://ispg.net/genetic-testing-statement/. Revised January 26, 2017. Accessed January 1, 2019.
4. Ellingrod VL, Ward KM. Using pharmacogenetics guidelines when prescribing: what’s available. Current Psychiatry. 2018;17(1):43-46.
5. U.S. Food and Drug Administration. Medical devices: direct-to-consumer tests. https://www.fda.gov/MedicalDevices/ProductsandMedicalProcedures/InVitroDiagnostics/ucm624726.htm. Published November 1, 2018. Accessed January 1, 2019.
6. U.S. Food and Drug Administration. FDA news releases: FDA authorizes first direct-to consumer test for detecting variants that may be associated with medication metabolism. https://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm624753.htm. Published October 31, 2018. Accessed January 1, 2019.
7. U.S. Food and Drug Administration. Medical devices: nucleic acid based tests. https://www.fda.gov/MedicalDevices/ProductsandMedicalProcedures/InVitroDiagnostics/ucm330711.htm. Published February 5, 2019. Accessed March 1, 2019.
8. U.S. Food and Drug Administration. Medical devices. The FDA warns against the use of many genetic tests with unapproved claims to predict patient response to specific medications: FDA Safety Communications. https://www.fda.gov/MedicalDevices/Safety/AlertsandNotices/ucm624725.htm. Published November 1, 2018. Accessed January 1, 2019.
9. Whirl-Carrillo EM, McDonagh JM, Hebert L, et al. Pharmacogenomics knowledge for personalized medicine. Clin Pharmacol Ther. 2012;92(4):414-417.
10. U.S. Food and Drug Administration. Drugs. Table of pharmacogenomic biomarkers in drug labeling. https://www.fda.gov/Drugs/ScienceResearch/ucm572698.htm. Published August 3, 2018. Accessed January 1, 2019.
11. U.S. Food and Drug Administration. Drugs@FDA: FDA approved drug products. https://www.accessdata.fda.gov/scripts/cder/daf. Accessed March 4, 2019.

Unfortunately, this information might be difficult to locate due to the lack of consistency regarding where it is placed in the FDA-approved drug labeling. The Pharmacogenomics Knowledgebase (https://www.pharmgkb.org/) can help clinicians quickly identify information regarding medications, their metabolic pathways, CPIC dosing guidelines, and the FDA-approved drug labeling information.⁹ By searching for specific medications within the Pharmacogenomic Knowledge Base, information regarding the FDA-approved drug labeling can be easily found, which is important because currently >120 medications contain pharmacogenomics information in their FDA-approved drug labeling.¹⁰

CASE CONTINUED

Overall Mr. R’s pharmacogenomics testing results indicate that he has 2 genotypes that are associated with poor metabolism phenotypes and could result in reduced metabolism of medications that are metabolized by these CYP enzymes, leading to higher blood levels and an increased risk of adverse effects. The Table¹¹ lists pharmacogenomics information from the FDA-approved drug labeling and from the Pharmacogenomics Knowledgebase for both the medications Mr. R has previously been prescribed and for several potential medications to consider.

It would be prudent to first discuss with Mr. R the FDA’s recent policy statement and safety communication. While you could recommend that he pursue additional pharmacogenomics testing, it is unclear which specific laboratory is available to conduct this confirmatory analysis.

Because Mr. R has had unsuccessful trials of several medications that primarily fall in the selective serotonin reuptake inhibitors class, it might be time to consider a medication from a different class. A quick review of the FDA-approved drug labeling for bupropion indicates that its metabolism is not dependent on CYP2D6 or CYP2C19, which might make this drug a good choice. Furthermore, the metabolism of venlafaxine does not appear to be influenced by CYP2D6 poor metabolism, which might also make it a good choice for Mr. R.

Related Resources

Gammal RS, Gardner KN, Burghardt KJ. Where to find guidance on using pharmacogenomics in psychiatric practice. Current Psychiatry. 2016;15(9):93-94.
Clinical Pharmacogenomics Implementation Consortium. What is CPIC? https://www.pharmgkb.org/page/cpic.

Drug Brand Names

Bupropion • Wellbutrin, Zyban
Citalopram • Celexa
Paroxetine • Paxil
Sertraline • Zoloft
Venlafaxine • Effexor

Pharmacogenomics testing: What the FDA says

References

CASE CONTINUED

Related Resources

Drug Brand Names

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