CYP2D6 Polymorphism and Characteristics
| Phenotype | Characteristics | Clinical Consequence |
|---|---|---|
| PM | Major variants: CYP2D6*3, -*4, -*5, -*6 | High plasma drug level |
| Enzyme inactive | Risk of drug-related side effects | |
| 5–10% White; 1–2% Chinese and Japanese | Use of reduced drug dose | |
| IM | Major variants: CYP2D6*9, -*10, -*41 | Lower dose for some patients |
| Low residual enzyme activity | ||
| EM | Not a uniform group | Standard dose for most patients |
| Normal rate of metabolism | ||
| UM | Multiple copies of CYP2D6 | Very low plasma drug level |
| Very high enzyme activity | Loss of drug efficacy | |
| 1–2% Whites; 30% Ethiopians | Higher drug dose required |
IM, intermediate metabolizer.