Chunk #19 — Current Status of Drug Labeling and Pharmacogenomic Testing Guidelines — Labeling for Phenytoin

Source

Pharmacogenomic testing for neuropsychiatric drugs: current status of drug labeling, guidelines for using genetic information, and test options.

Embedded

yes

Text

In addition to the recommendation for HLA-B*1502-positive subjects, the Dutch Pharmacogenetics Working Group provides dose recommendations for carriers of CYP2C9 variants in patients treated with phenytoin, which is a major substrate for this metabolic pathway.35 This recommendation outlines a 25% dose reduction for CYP2C9*1/*2 or *1/*3 and a 50% dose reduction for *2/*2, *2/*3, or*3/*3 carriers. However, this recommendation is not reflected in the latest phenytoin drug label.