title: Clopidogrel dose adjustment after outpatient screening for CYP2C19 variant alleles: a pilot study.
abstract: This pilot study examined the feasibility of outpatient screening and clopidogrel dose adjustment for patients with previous percutaneous coronary intervention and at least one CYP2C19 loss-of-function allele. After screening a total of 211 outpatients, 50 patients were enrolled in a crossover study comparing 30 days of standard dose (75 mg) to 30 days of high-dose clopidogrel (150 mg). Platelet function was assessed with the VerifyNow P2Y12 assay. In patients with CYP2C19*2, 150 mg daily of clopidogrel was associated with improved ADP-specific platelet inhibition (217 vs 258 P2Y12 reaction units, p = 0.01). Outpatient screening for CYP2C19 loss-of-function polymorphisms is feasible, and a strategy of clopidogrel dose escalation may improve platelet inhibition in appropriately selected patients.
authors: Division of Cardiology, University of North Carolina, Chapel Hill, NC, USA.
authors: Joseph S
authors: JS
authors: Rossi
authors: Michael
authors: M
authors: Cammarata
authors: Jayalalitha
authors: J
authors: Dharmavaram
authors: Karen
authors: K
authors: Weck
authors: Christine
authors: C
authors: Walko
authors: Don
authors: D
authors: Gabriel
authors: Jack
authors: J
authors: Kuritzky
authors: Kenneth
authors: K
authors: Muldrew
authors: George A
authors: GA
authors: Stouffer
mesh_terms: D000368:Aged; D000483:Alleles; D001792:Blood Platelets / Q000378:metabolism / Q000473:pathology; D000077144:Clopidogrel; D065731:Cytochrome P-450 CYP2C19 / Q000235:genetics*; D004305:Dose-Response Relationship, Drug; D005260:Female; D005820:Genetic Testing; D006801:Humans; D008297:Male; D008875:Middle Aged; D010045:Outpatients; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage*; D013988:Ticlopidine / Q000031:analogs & derivatives* / Q000627:therapeutic use
chemical_list: D010975:Platelet Aggregation Inhibitors; D000077144:Clopidogrel; D065731:Cytochrome P-450 CYP2C19; D013988:Ticlopidine
keywords: clopidogrel; genetic testing; platelet function; polymorphism