DefinitionBy Mayo Clinic staff
Your doctor may use cytochrome P450 tests (CYP450 tests) to help determine how your body processes (metabolizes) a drug. Our bodies contain numerous P450 enzymes to process medications. Because of inherited (genetic) traits which cause variations in these enzymes, medications affect each person differently.
The P450 enzyme with the most variation in different people is the 2D6, which processes many antidepressants and antipsychotic medications. By checking your DNA for certain gene variations, cytochrome P450 tests can offer clues about how your body may respond to a particular antidepressant. Other cytochrome P450 tests are available for other enzymes.
Cytochrome P450 and other genetic tests (genotyping tests) are becoming more common as doctors try to understand why antidepressants help some people and not others. While their use might be increasing, there are limitations.
- Mrazek DA. Psychiatric pharmacogenomic testing in clinical practice. Dialogues in Clinical Neuroscience. 2010;12:69.
- Wand L, et al. Genomics and drug response. The New England Journal of Medicine. 2011;364:1144.
- Goetz MP. Update on CYP2D6 and its impact on tamoxifen therapy. Clinical Advances in Hematology & Oncology. 2010;8:536.
- McAlpine DE, et al. Effect of cytochrome P450 enzyme polymorphisms on pharmacokinetics of venlafaxine. Therapeutic Drug Monitoring. 2011;33:14.
- Fleeman N, et al. Cytochrome P450 testing for prescribing antipsychotics in adults with schizophrenia: Systemic review and meta-analysis. The Pharmacogenomics Journal. 2011;11:1.
- Genetic testing — CYP450 genotyping to predict response to SSRIs used to treat non-psychotic depression in adults: EGAPP recommendation. Centers for Disease Control and Prevention. http://www.cdc.gov/genomics/gtesting/EGAPP/recommend/CYP450.htm. Accessed Aug. 29, 2012.
- Steimer W. Pharmacogenetics and psychoactive drug therapy: Ready for the patient? Therapeutic Drug Monitoring. 2010;32:381.
- Mrazek DA, et al. Facilitating clinical implementation of pharmacogenomics. JAMA. 2011:306:304.
- Kung S (expert opinion). Mayo Clinic Rochester, Minn. Aug. 15, 2012.
- Coumadin (prescribing information). Princeton, N.J.: Bristol-Myers Squibb Company; 2011. http://packageinserts.bms.com/pi/pi_coumadin.pdf. Accessed Aug. 21, 2012.