Conversion from fluvastatin to simvastatin therapy at a dose ratio of 8 to 1: effect on serum lipid levels and cost.

The objective of this study was to assess the effect on serum lipid levels of the substitution of simvastatin for fluvastatin at a dose ratio of 8:1 (fluvastatin to simvastatin). A secondary objective was to determine the number of patients at goal lipid levels before and after this substitution. The study included 60 outpatients with hyperlipidemia who had received a constant dose of fluvastatin for at least 6 weeks. After a baseline 12-hour lipid profile (total cholesterol, triglycerides, high-density lipoprotein, and low-density lipoprotein [LDL]) was obtained, patients were switched from fluvastatin to simvastatin at an 8:1 dose ratio. Patients were instructed to split the simvastatin tablets in half with a pill splitter and to take one half-tablet at bedtime. A repeat lipid profile and liver function testing were performed after 6 to 8 weeks of simvastatin therapy. Lipid components were compared before and during simvastatin therapy using a paired t test. Target LDL levels were based on guidelines issued by the National Cholesterol Education Program. Fifty-six patients completed the study. No change in lipid components was observed, except for a statistically significant decrease in LDL. The majority of patients had a decrease in LDL levels, rather than an increase, after the conversion to simvastatin. Six patients required a dose increase of simvastatin in response to increased LDL levels. Forty-one percent of patients achieved goal LDL levels with simvastatin, compared with 30% with fluvastatin. Four patients withdrew from the study, two because of troublesome side effects and two for failure to complete the protocol. The results show that simvastatin can be substituted for fluvastatin at a dose ratio of 8:1 without loss of lipid control in the majority of patients and that by using this ratio and splitting tablets, significant cost savings can be realized.