What Genes Are TestedCYP2D6 (cytochrome P450 2D6) is the best studied of the DMEs and acts on one-fourth of all prescription drugs, including the selective serotonin reuptake inhibitors (SSRI), tricylic antidepressants (TCA), betablockers such as Inderal and the Type 1A antiarrhythmics. Approximately 10% of the population has a slow acting form of this enzyme and 7% a super-fast acting form. Thirty-five percent are carriers of a non-functional 2D6 allele, especially elevating the risk of ADRs when these individuals are taking multiple drugs. Drugs that CYP2D6 metabolizes include Prozac, Zoloft, Paxil, Effexor, hydrocodone , amitriptyline, Claritin, cyclobenzaprine, Haldol, metoprolol, Rythmol, Tagamet, tamoxifen, and the over-the-counter diphenylhydramine drugs, Allegra, Dytuss, and Tusstat. CYP2D6 is responsible for activating the pro-drug codeine into its active form and the drug is therefore inactive in CYP2D6 slow metabolizers. CYP2C9 (cytochrome P450 2C9) is the primary route of metabolism for Coumadin (warfarin). Approximately 10% of the population are carriers of at least one allele for the slow-metabolizing form of CYP2C9 and may be treatable with 50% of the dose at which normal metabolizers are treated. Other drugs metabolized by CYP2C9 include Amaryl, isoniazid, ibuprofen, amitriptyline, Dilantin, Hyzaar, THC (tetrahydrocannabinol), naproxen, and Viagra. CYP2C19 (cytochrome P450 2C19) is associated with the metabolism of carisoprodol, diazepam, Dilantin, and Prevacid. CYP1A2 (cytochrome P450 1A2) is associated with the metabolism of amitriptyline, olanzapine, haloperidol, duloxetine, propranolol, theophylline, caffeine, diazepam, chlordiazepoxide, estrogens, tamoxifen, and cyclobenzaprine. NAT2 (N-acetyltransferase 2) is a second-step DME that acts on isoniazid, procainamide, and Azulfidine. The frequency of the NAT2 "slow acetylator" in various worldwide populations ranges from 10% to more than 90%. VKORC1 and CYP2C9 for warfarin (Coumadin) UGT1A1(UDP-glucuronosyltransferase) for irinitecan (Campostar). DPD (Dihydropyrimidine dehydrogenase) for Fluorouracil (5-FU).
The Testing ProcessThe process is simple. You can order testing directly if you have a physician prescription or your healthcare provider can request testing for you. We send a cheek swab collection kit with directions by mail. Use the return mailer to submit samples and receive results in ten days or less. Faster testing is available for an additional charge. Call a DNA testing consultant at (800) 523-3080 for details and to order. Note: Testing is currently not available to New York residents and requires a prescription from a physician. Check Common Drugs Processed by Enzymes We Test
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