The AmpliChip CYP450 Test Helps Figure Out Which Antidepressant is Best for YouIf you or a loved one are being treated for major depression, you probably already know that finding the right antidepressant is not always a straightforward process. The ‘right’ antidepressant should provide the most effective medication with the fewest side effects. And what’s right for one person might not be right for someone else.
Because medications, including antidepressants, affect people in different ways, it can often take months—sometimes years—before you find the ‘right antidepressant’ – the treatment that works best for you. It can be a trial and error process.
Recently, a genetic test was developed that can make finding the right medication a whole lot easier. The test, called the AmpliChip CYP450 Genotyping Test, analyzes specific genes that are involved in the way your body processes, or ‘metabolizes’ certain medicines, including antidepressants. This is important because we don’t all process drugs in the same way—and these differences among us can cause variations in the way we react to medications. For example, if your genetic make-up pre-disposes you to process a particular antidepressant very slowly, the drug can remain in your body longer than it was designed to. As an effect, the medication can build up in your system and cause unpleasant side effects and possibly a serious reaction. At this point, a person might decide, quite understandably, to stop taking that medication.
On the other hand, if your body processes antidepressants too rapidly, the drug might pass through your system before it has had a chance to fully take effect. This could result in the drug not having much of an impact on your symptoms.
If your doctor could know in advance which drugs you will metabolize best, he or she could choose the medication and dosage that’s most suited to your genetic make-up.
The CYP450 Test looks at how your body produces certain chemicals called ‘enzymes’. By looking at certain genes, the test determines whether or not you are producing normal versions of certain enzymes needed to process antidepressants. The results will let your doctor know how your body metabolizes a drug, whether it is likely to work, and whether or not you could experience any severe side effects.
In order to do the test, a blood sample is required. It is very straightforward, and doesn’t involve any special preparation or fasting.
If the results show that you are a ‘fast metabolizer’ your physician can then increase the dosage or change the antidepressant you’re currently taking. If you are a ‘slow metabolizer’ your physician has the option to switch your medication or change your dosage.
If you produce the normal amount of enzymes, you should follow the prescribed dosage and, with your doctor’s supervision, monitor your progress.
It is important to be aware that you should never change the dosages of your medications, or the frequency with which you take them without your doctor’s supervision or instruction.
While this Amplichip test can predict how your body will process a drug, it cannot show how effective it will be in treating your symptoms. The test can only indicate whether a drug has a better chance of being effective because it suits your metabolism.
Also, the CYP450 test works only for antidepressants that are metabolized by the two genes it is able to test.
And, while the CYP450 test is approved by the Federal Food and Drug Administration in the United States, it may not be available where you live. If it is, it shouldn’t be the only tool used to determine your treatment, but should complement a thorough medical exam and psychiatric evaluation. Another important point to note is that some medical insurers may not cover the cost of the test.
Effexor and Effexor XR are registered trademarks of Wyeth Pharmaceuticals Inc. Tofranil is a registered trademark of Mallinckrodt Inc. Norpramin is a registered trademark of Hoechst-Marion-Roussel Pamelor is a registered trademark of Sandoz Pharmaceuticals Paxil and Paxil CR are registered trademarks of GlaxoSmithKline Prozac and Prozac weekly are registered trademarks of Eli Lilly and Company. Limbitrol and Limbitrol DS are registered trademarks of ICN Pharmaceuticals, Inc Elavil is a registered trademark of Astra Zeneca Pharmaceuticals, Endep is a registered trademark of Roche Laboratories Anafranil is a registered trademark of Mallinckrodt Inc.
If you have a comment email claire@knowitallhealth.com
Reviewed: June 24 2007
The genetic AmpliChip CYP450 Test is part of a growing field in medicine called pharmacogenetics. Pharmacogenetics helps physicians identify appropriate drugs and dosages for individual patients. The AmpliChip test looks at differences in your body’s genetic code for the enzymes CYP2D6 and CYP2C19. These enzymes are among those used by your body to process antidepressants.
The following antidepressants are processed by the CYP2D6 enzyme, and are listed by brand name with the generic names in brackets:
These antidepressants are metabolized by the CYP2C19 enzyme:
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