OBJECTIVES: We compared healthcare resource utilization (hospitalizations, physician visits, prescriptions) between users of pravastatin, lovastatin, and simvastatin. METHODS: Manitoba s Health Research Database identified statin users between 95/1/1 and 98/3/31. Incident users received a first prescription for a statin after 95/4/30; prevalent users had a prescription before 95/5/1. Statin interacters were on >1 prescription for an interacting drug while on a statin (Group A drugs levels were increased; Group B drugs increased levels of statins). Wilcoxon s ranksum test analyzed differences by statin on healthcare resource use. RESULTS: 24,555 statin users (15,148 incident and 9,407 prevalent) were identified. 19,850 (80.8%) individuals took one statin; 16.7% took two statins. Most common Group A interactions were with warfarin (9.7%), amitriptyline (4.4%), and imipramine (4.4%); in Group B, itraconazole (10.8%), omeprazole (6.7%), and clarithromycin (4.4%) were the most common. Statin interacters consumed significantly more healthcare resources than did noninteracters for both incident and prevalent analyses. New pravastatin users taking interacting drugs had on average significantly fewer hospitalizations (0.85) and physician visits (19.33), and lower healthcare costs ($3,954) compared to new users of lovastatin (1.21, 22.03, $5,559) and simvastatin (1.07, 21.21, $4,734). The comparison of prevalent users was only significant between lovastatin and pravastatin. CONCLUSION: Pravastatin is associated with less healthcare resource utilization in new users, possibly due to lack of interaction effects. In prevalent users, the differences were minimized, possibly due to adjustments in drug and dosage regimens.