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the free encyclopedia
Drug reaction testing
uses a
genetic test to predict how a
particular person will respond to
various prescription and
non-prescription
medications. It checks for
genes that code for specific
liver
enzymes which activate,
deactivate, or are influenced by
various drugs.
There are currently four
genetic markers commonly
tested for: 2D6, 2C9, 2C19, and
1A2.
This testing has been done for
some time by drug companies
working on new drugs, but is
relatively newly available to the
general public.
Strattera is the first drug to
mention the test in the official
documentation, although it doesn't
specifically recommend that
patients get the test before
taking the medication.
There are four possible
categories for each marker:
poor metabolizer,
intermediate metabolizer,
extensive metabolizer, or
ultra-extensive metabolizer.
Different testing companies may
call these by different names.
Extensive metabolizers (that is,
people who are extensive
metabolizers of a given type) are
the most common, and are the type
of people for which drugs are
designed. Up to 7% of Caucasians
are poor metabolizers of drugs
metabolized by the
CYP2D6 enzyme.[1]
People who can't
metabolize a drug will require
a much lower dose than is
recommended by the manufacturer,
and those who metabolize it
quickly may require a higher dose.
Some drugs, such as
codeine, will not be effective
in people without the requisite
enzymes to activate them.
People who are poor
metabolizers of a drug may
overdose while taking less than
the recommended dose.
References and End Notes
