Pharmacogenomic topic · dashboard states: NM · PM · IM · UM
PGx describes inherited differences in drug handling. AUC measures total exposure, not benefit or toxicity by itself. Ask whether the pathway clears a drug or activates it: slower clearance can raise exposure; slower activation can reduce benefit. Lower inactive-metabolite exposure does not imply lost efficacy.
Dashboard vocabulary: NM = Normal metabolizer; PM = Poor metabolizer; IM = Intermediate metabolizer; UM = Ultrarapid metabolizer. RM = Rapid metabolizer appears only under CYP2C19; EXP = Expresser appears only under CYP3A5. These interface labels do not establish clinical phenotypes for every gene. Prescribing uses the laboratory report, current guidance and monitoring.
Test at a glance
Encodes DPD, which breaks down fluorouracil.
Clinical role
Deficiency can cause fatal fluorouracil or capecitabine toxicity. Complete deficiency generally means avoidance; partial deficiency needs individualized oncology dosing.
Practical pearls
Capecitabine becomes fluorouracil: unchanged parent-drug exposure does not remove risk.
Dashboard UM is not a standard CPIC dosing category.
Safety / monitoring
Test before systemic treatment unless immediate treatment is necessary. Early severe diarrhea, mouth sores, fever or confusion require urgent assessment.
Self-check
Why does DPYD matter for capecitabine? Its fluorouracil metabolite needs DPD clearance.
Does a negative test guarantee safety? No. Toxicity can still occur.