ABSTRACT
<b>Objective: </b>The purpose of this study is to compare the clinical efficacy between original drugs and generic products. Candidate drugs included two types of hydroxymethylglutaryl-CoA (HMG-CoA) reductase inhibitors, simvastatin and pravastatin, because of their importance at reducing the health expenditure for hyperlipidemia.<br><b>Design: </b>We retrospectively evaluated the efficacy (total cholesterol, triglyceride, low-density lipoprotein and high-density lipoprotein levels), safety (biochemical parameters), and medication adherence based on patient data. We set the follow-up period at 6 months before and after substitution. Data were analyzed by paired-sample <i>t</i>-tests (statistical significance level of 0.05).<br><b>Methods: </b>The subjects included in this study were ambulatory patients visiting Nakajima Hospital for dyslipidemia treatment. Selected patients included those taking both the original drug and the generic product; i.e., patients who had substituted the original drug Lipovas® for the generic product Simvastatin OHARA, or those who had substituted the original drug Mevalotin® for the generic drug Pravatin®.<br><b>Results: </b>A total of 118 patients in the simvastatin study and 43 patients in the pravastatin study were candidates for the present study. We found that there were no significant differences before and after substitution. Even though there were differences in some of the biochemical parameters, the range remained within normal levels. With regard to medication adherence, we found no significant differences.<br><b>Conclusion: </b>In this study, we found no significant differences before and after substituting medications with generic drugs. Additionally, we found no subjective symptom changes after substitution. To develop clinical information on generic products and to store such information, it is important that pharmaceutical products be used appropriately.