Pharmacogenetic


Pharmacogenetics describes genetic tests which allow the accurate assessment how different drugs are metabolized in our body, based on genetic features.

These tests help with the exact dosage of medication for patients who

– take a lot of different drugs (like pain meds)

– already had reactions to drugs

– did not respond to specific drugs

These genetic tests enable the doctors to better dose a drug and to avoid adverse reactions.

 

Cytochrome P450 tests

CYP450 genes are a gene family which encode for a variety of CYP enzymes. These enzymes are responsible for metabolizing around 85 percent of all drugs in the body.

The clinical relevant are: CYP1A2, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP2E1, and CYP3A4.

Every drug is metabolized through one ore more pathways. If there are any changes of the genes which encode the enzymes the metabolization of the drug is changed.

Depending on the genetic characteristic it is differentiated in:

“Extensive metabolizer”: normal metabolizer

“Intermediate metabolizer”: normal or decreased metabolizer

“Poor metabolizer”: poor metabolizer are not able to metabolize specific drugs which may lead to increased concentration of this medication in the body. This could cause overdosing and adverse reactions.

“Ultra-rapid metabolizer”: ultra-rapid metabolizer metabolize specific drugs very quickly which my lead to ineffective medications (in normal dose). Ultra-rapid metabolizer may need an increased drug dose.

 

Buccal swabs or a blood sample is used for testing.

 

More information and lists of substrates and inhibitors:

http://genelex.com
http://www.genetworx.com/pdf/genetworx%20-%20pharmacogenomic%20testing%20in%20clinical%20practice.pdf