PGX (Drug Transporters) Flashcards
DM:DX Ratio
Dextromethorphan (DM)
- Probe Drug
Dextrorphan (DX)
- Metabolite
High Ratio
= Poor Metabolizer
Low Ratio
= Extensive Metabolizer
Extensive Metabolizer
Carries two normal function allele
(1/1)
Intermediate Metabolizer
One Normal + One Decreased function allele
(1/2)
OR
One Normal + One No function allele
(1/3)
OR
Two Decreased Function Allele
(2/2)
Poor Metabolizer
One No Function + One Decreased Function
OR
Two No Function alleles
Two Normal Function Allele
Normal Metabolizer
One Normal
+
One Decreased Function
Intermediate Metabolizer
One Normal
+
One No Function
Intermediate Metabolizer
Two Decreased Function
Intermediate Metabolizer
One No Function
+
One Decreased Function
Poor Metabolizer
Two No Functions
Poor Metabolizer
Ethnicity and Drug Dosing
Use individual’s ethnicity to determine if there is a risk of them receiving a toxic dose
Types of Transporters
ATP-Binding Cassette (ABC) Family Transporters
Solute Carrier Family Transporters
Where are efflux/influx transporters found
Intestine
Liver
Kidney
Brain
Clinically Important ABC
- What gene encodes it
- What transport does it facilitate
ABCB1 (Multidrug Resistant 1/MDR 1)
- Encodes P-glycoproteins
Involved in efflux of chemotherapeutic agents
ABC and Cancer
Cancer Cells overproduce P-Glycoproteins (An ABC)
Too much P-Glycoproteins means cell ejects therapeutic drugs from the cell
