Table 3.
Genotypes and their associated metabolizer phenotypes
| Metabolizer activity | Gene | Allele activity | Enzyme-oriented approach | Drug-oriented approach |
| Ultrarapid metabolizer | CYP2C9 | Unknown | – | – |
| CYP2C19 | Increased/increased | – | – | |
| CYP2D6 | Wild-type/increased; increased/increased | – | – | |
| CYP3A5 | Unknown | – | – | |
| Extensive metabolizer | CYP2C9 | Wild-type/wild-type | *1/*1,*1/*2,*1/*3 (*1=wild-type, *2=decreased, *3=wild-type) | *1/*1,*1/*2 (*1=wild-type, *2=decreased) |
| CYP2C19 | Wild-type/wild-type | *1/*1,*1/*2 (*1=wild-type, *2=decreased) | *1/*1 (*1=wild-type) | |
| CYP2D6 |
|
*1/*1,*1/*4, *1/*6,*1/*10 (*1=wild-type, *4=decreased, *6=wild-type, *10=decreased) | *1/*1,*1/*4,*1/*6,*1/*10 (*1=wild-type, *4=non-functional, *6=non-functional, *10=non-functional) | |
| CYP3A5 | Unknown | *1/*1,*1/*3 (*1=wild-type, *3=decreased) | *1/*1,*1/*3 (*1=wild-type, *3=non-functional) | |
| Intermediate metabolizer | CYP2C9 | Wild-type/non-functional | *2/*2 (*2=decreased) | *1/*3,*2/*2 (*1=wild-type, *2=decreased, *3=non-functional) |
| CYP2C19 | Wild-type/non-functional | – | *1/*2 (*1=wild-type, *2=non-functional) | |
| CYP2D6 |
|
*4/*4 (*4=decreased) | – | |
| CYP3A5 | Unknown | *3/*3 (*3=decreased) | *3/*3 (*3=non-functional) | |
| Poor metabolizer | CYP2C9 | Non-functional/non-functional | – | – |
| CYP2C19 | Non-functional/non-functional | – | – | |
| CYP2D6 | Non-functional/non-functional | – | *4/*4 (*4=non-functional) | |
| CYP3A5 | Unknown | – | – | |
The ‘Allele activity’ column of this table is adapted from Sheffield and Pillimore2 (review article). ‘increased,’ ‘wild-type,’ ‘decreased,’ and ‘non-functional’ refer to associated allelic activity.