title: Assessment of steady-state clopidogrel reactivity by using platelet reactivity units.
abstract: Platelet function testing is an important laboratory measure in clopidogrel treatment. We sought to investigate the stability of the reactivity of clopidogrel after 1 month of treatment. A prospective analysis was carried out using a matched study design to compare platelet reactivity units (PRUs) and platelet inhibition in clopidogrel-treated patients. Patients with various cardiac diseases were divided into 2 matched groups. The first group was treated on an inpatient acute basis, and the other group was treated on an outpatient chronic basis. PRU was measured 5 days after clopidogrel administration in the acute group and 1 month after chronic use for several cardiac indications in the second group. VerifyNow (Accumetrics) was used to detect platelet reactivity and calculate inhibition rates in response to clopidogrel. A total of 260 Saudi patients were enrolled, including 90 inpatients and 170 outpatients. A significant difference was observed in PRU (173.69 vs. 195) and percent inhibition (24.05% vs. 16.13%) between the outpatient and inpatient groups. Platelet function evolves over time and initial readings may not be constant.
authors.affiliation: Departments of 1Cardiology and 2Cardiac Intervention, Prince Sultan Cardiac Centre, Buraidah, Kingdom of Saudi Arabia; and 3Department of Pharmacology and Therapeutics, College of Medicine, Qassim University, Buraidah, Kingdom of Saudi Arabia.
authors.forename: Seemab
authors.initials: S
authors.lastname: Rasool
authors.forename: Hassan
authors.initials: H
authors.lastname: Khalaf
authors.forename: Ahmad
authors.initials: A
authors.lastname: Almeman
authors.forename: Mohammad M
authors.initials: MM
authors.lastname: AlOrainy
mesh_terms: D000328:Adult; D000368:Aged; D000077144:Clopidogrel; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology*; D011446:Prospective Studies; D058921:Purinergic P2Y Receptor Antagonists / Q000494:pharmacology*; D013988:Ticlopidine / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: D010975:Platelet Aggregation Inhibitors; D058921:Purinergic P2Y Receptor Antagonists; D000077144:Clopidogrel; D013988:Ticlopidine