Most recent guideline publication:
Clinical Pharmacogenetics Implementation Consortium (CPIC) Guidelines for CYP2C9 and HLA-B Genotype and Phenytoin Dosing (August 2020)
Updates since publication:
No updates on dosing recommendations since publication.
Tables and figure provided in the main manuscript of the guideline:
|Table 1. Assignment of likely HLA-B phenotypes based on genotypes|
|Table 2. Assignment of likely CYP2C9 phenotypes based on genotypes|
|Table 2. Recommended dosing of phenytoin/fosphenytoin based on HLA-B*15:02 and CYP2C9 phenotype/genotype|
|Figure 1. Algorithm for suggested clinical actions based on HLA-B*15:02 and CYP2C9 genotype|
Supplement to: Clinical Pharmacogenetics Implementation Consortium (CPIC) Guidelines for CYP2C9 and HLA-B Genotype and Phenytoin Dosing (August 2020)
Tables and figures included in the supplement or referenced in the guidelinea:
|Supplemental Table S1. Evidence linking HLA allele to phenytoin cutaneous adverse drug reaction phenotype|
|Supplemental Table S2. Evidence linking CYP2C9 genotype to phenytoin metabolism and/or toxicities|
|Supplementary Figure S1. Metabolism of phenytoin or see PharmGKB Phenytoin Pathway, Pharmacokinetics|
|Supplementary Figure S2. Metabolism of fosphenytion to phenytoin|
|HLA-B frequency tables|
|CYP2C9 allele definition table|
|CYP2C9 allele functionality table|
|CYP2C9 frequency table|
|CYP2C9 diplotype-phenotype table|
Gene resource mappings
Drug resource mappings
Clinical decision supportb:
aSome of the tables included in the guideline may have been updated online, particularly to reflect newly described or newly characterized alleles. These include the gene-specific information tables (https://www.pharmgkb.org/page/pgxGeneRef) 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.
Original guideline (November 2014)
- Clinical Pharmacogenetics Implementation Consortium (CPIC) Guidelines for CYP2C9 and HLA-B Genotype and Phenytoin Dosing (November 2014)
- 2014 Supplement
This guideline has been endorsed by the American Society of Health-System Pharmacists (ASHP).