Cytochromes P450, Drugs, and Diseases

Relative rates of CYP2D6 activity in a Caucasian population (4). CYP2D6 activity is represented as the ratio of unmetabolized drug (here, debrisoquine) to drug metabolite (4-hydroxydebrisoquine) collected from the urine following a single dose. The distribution is the result of the existence of more than seventy alleles in the population (see http://www.imm.ki.se/CYPalleles/). Early research labeled individuals as “extensive metabolizers” (green) and “poor metabolizers” (blue) (5). The “ultrarapid metabolizer” phenotype (red) can result from inherited gene amplification (6).