OBJECTIVE: The five statins currently available in the US (atorvastatin [A], pravastatin [P], simvastatin [S], fluvastatin [F] and lovastatin [L]) differ in terms of their abilites to lower LDL-C, the need to adjust dosing for decreased renal function, potential for drug-drug interactions, cost, recommended hepatic function monitoring schedule, and level of proven effectiveness. The implications of these differences on the clinical use of statins have been largely unexplored. The purpose of this study was to examine the effects of these intra-class differences on clinical decision making using multicriteria decision analysis. METHODS: A multicriteria decision analysis using the Analytic Hierarchy Process (AHP) was performed from the practitioner's perspective. The goal was defined as "Choose the best statin". Decision criteria were based on the differences mentioned above. Costs were included in the analysis both as internet drug store prices (scenario 1) and in terms of patient co-pays for 3 current three-tiered managed care formularies in Rochester, NY (scenarios 2,3, & 4). Data comparing the statins' performance on the other criteria were obtained from the literature. RESULTS: Statin priority scores, which measure the relative rankings of the alternatives' abilities to meet the all decision criteria (higher scores are better), for the 4 scenarios are: Scenario 1: L=0.214, F=0.209, P=0.200, S=0.190, A=0.187; Scenario 2: P=0.209, L=0.208, S=0.205, F=0.192, A=0.188; Scenario 3: P=0.213, L=0.208, S=0.200, A=0.192, F=0.187; Scenario 4: P=0.209, L=0.208, S=0.205, A=0.192, F=0.187. In addition to cost, relative priority scores in all scenarios were affected by differences in the importance assigned to ability to lower LDL-C, ease of prescribing safely, and proven effectiveness. CONCLUSION: The relative importance of differences among statins has a significant impact on optimal clinical use of these drugs. These results suggest that practitioners should be aware of these differences and incorporate them in clinical decisions regarding statin prescriptions.