CPIC® Guideline for Tamoxifen based on CYP2D6 genotype

Most recent guideline publication:

Clinical Pharmacogenetics Implementation Consortium (CPIC) Guideline for CYP2D6 and Tamoxifen Therapy (January 2018) 

Updates since publication:

No updates on dosing recommendations since publication.

Tables provided in the main manuscript of the guideline:

Table 1. Assignment of likely CYP2D6 phenotypes based on diplotypes
Table 2. Dosing Recommendations for tamoxifen based on CYP2D6 phenotype

Supplement to: Clinical Pharmacogenetics Implementation Consortium (CPIC) Guideline for CYP2D6 and Tamoxifen Therapy (January 2018)

Tables and figures provided in the guideline publication supplement or referenced in the guidelinea:

Supplemental Table S1. Association between allelic variants and CYP2D6 enzyme activity
Supplemental Table S2. Evidence linking CYP2D6 to tamoxifen phenotype
CYP2D6 allele definition table
CYP2D6 allele functionality table
CYP2D6 frequency table
CYP2D6 diplotype-phenotype table

Gene Resource Mapping

CYP2D6 gene resource mappings

Drug Resource Mapping


Clinical Decision Support:b

Tamoxifen pre- and post-test alerts and flow chart

aSome of the tables included in the guideline may have been updated on-line, particularly to reflect newly described or newly characterized alleles. These include the gene-specific information tables ( that support CPIC guidelines by providing information regarding star (*) allele definitions, allele function, allele frequency by major ethnic groups, translations of diplotype to phenotype, and gene resource mappings.

bThese resources support the adoption of CPIC guidelines into the electronic health record with clinical decision support and provide information that clinical implementers find helpful.

This guideline has been endorsed by the American Society of Health-System Pharmacists (ASHP).