OBJECTIVES: Long-term antiplatelet therapy is typically considered standard of care for secondary prevention of cardiac events. The goal of this study was to examine patterns of use and total health care utilization in patients receiving clopidogrel. METHODS: The study used a random subset of the Pharmetrics Patient-Centric Database (2001-2002) representing 3 million commercially insured members. Inclusion criteria were: index prescription for clopidogrel preceded by a 3-month drug free pre-period, followed by a 6-month post-period. RESULTS: Of 11,000 patients included; mean age was 63.7, 58% were male, 74% were Health Maintenance Organization members. Common comorbidities included: diabetes 24%, myocardial infarction 16%, acute coronary syndrome 18%, angina 18%, coronary heart disease 57%, stroke/transient ischemic attack 24%. Pre-period resource utilization showed 33% had an Emergency Room (ER) encounter, 58% were hospitalized, 58% had a cardiologist encounter, 38% a general practitioner (GP) encounter. Mean total charges were $25,807. Percutaneous coronary intervention (PCI) was also common (38.6%). In the post-period, 24% had an ER encounter, 54% were hospitalized, 44% had a cardiologist encounter, 63% a GP encounter. Mean total charges were $17,357. PCI occurred in 8.4% during the post-period. Sixty-seven percent of patients received the index clopidogrel prescription within 7 days of an ER encounter. Mean length of clopidogrel therapy was 86 days. Patterns of use showed 67% Stopped (not on clopidogrel 28-days prior to end of follow-up), 82% with a Gap (refills were >14 days apart). Concomitant statin use occurred in 57% (atorvastatin 32%). CONCLUSIONS: As defined by an index prescription, substantial resources were used both pre and post-period and coronary intervention was common. Long-term adherence to clopidogrel was poor and did not meet current guidelines. Patients receiving clopidogrel had many comorbidities and were high utilizers of health care resources, suggesting the need for better guideline compliance and perhaps better treatments.