OBJECTIVE: Consensus treatment guidelines recommend most patients with acute coronary syndrome (ACS) receive antiplatelet therapy, statins, and beta-blockers for prevention of secondary events. The goal of this review was to examine prescribing patterns of these agents from published naturalistic studies and compare to guideline recommendations. METHODS: An OVID Medline search was conducted from 1995 to 2004 to identify published naturalistic studies of ACS treatment that contained detailed drug utilization data. Drug utilization patterns were examined for two aspects: associated therapeutic strategy (medical therapy or percutaneous coronary intervention [PCI]) and initiation of drug therapy (acutely or as chronic therapy after hospital discharge). RESULTS: Four sources that contained sufficient details on drug utilization were identified. Data were from US and worldwide studies. Beta-blockers had the highest overall utilization (50-87% acute; 41-77% chronic). Statins were administered to 43-57% of patients acutely and 44-68% chronically. Insufficient data were available to examine associated therapeutic strategy for beta-blockers and statins. Clopidogrel use, with or without aspirin, ranged from 16-30% acutely. In the subgroup of patients who received PCI, clopidogrel use in the hospitalization period ranged from 51-83%. The percentage of ACS patients who received clopidogrel chronically was 38-66%, however in the subgroup of patients who underwent PCI, up to 83% received clopidogrel after hospital discharge. Insufficient data were available to examine duration of therapy. CONCLUSIONS: Recent treatment guidelines recommend use of beta-blockers, statins, and antiplatelet therapy in ACS patients. Some of the data reviewed here predates the most recent guidelines but they suggest a gap between the usual care setting and treatment guidelines. The largest discrepancy appears to be with chronic statin use and clopidogrel use in ACS patients who do not undergo PCI. Few data regarding duration of therapy are available. Continued guideline education and reinforcement along with quality improvement measures are needed.