Table 2.

CPIC (2016) CYP2C19 Functional Status and Phenotypes

PhenotypeGenotypeExamples of diplotypes
CYP2C19 ultrarapid metabolizer
(~2–5% of patients)a		An individual carrying 2 increased function alleles. *17/*17
CYP2C19 rapid metabolizer
(~2–30% of patients)		An individual carrying one normal function allele and one increased function allele. *1/*17
CYP2C19 normal metabolizer
(~35–50% of patients)		An individual carrying 2 normal function alleles. *1/*1
CYP2C19 intermediate metabolizer
(~18–45% of patients)		An individual carrying one normal function allele and one no function allele, or one no function allele and one increased function allele. *1/*2
*1/*3
*2/*17b
CYP2C19 poor metabolizer
(~2–15% of patients)		An individual carrying 2 no function alleles. *2/*2
*2/*3
*3/*3
a

CYP2C19 metabolizer status frequencies are based on average multiethnic frequencies. See the CYP2C19 Frequency Tables for population-specific allele and phenotype frequencies (23).

b

The predicted metabolizer phenotype for the*2/*17 genotype is a provisional classification. The currently available evidence indicates that the CYP2C19*17 increased function allele is unable to completely compensate for the CYP2C19*2 nonfunctional allele.

This table is adapted from (23).

From: Brivaracetam Therapy and CYP2C19 Genotype

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Pratt VM, Scott SA, Pirmohamed M, et al., editors.
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