Evaluation of glycaemic control comparing originator versus generic fixed‐dose glibenclamide/metformin tablet among diabetes mellitus patients in an outpatient clinic

Abstract

Background: Currently, comparison studies on glycaemic control by originator versus generic fixed-dose antidiabetic drugs are limited. Aim: This study assessed the efficacy, adherence and adverse effects between originator and generic fixed-dose glibenclamide/metformin after switching from gliclazide coadministered with metformin, and after interchanging the originator and generic fixed-dose tablets between the study groups. Methods: A prospective randomised cross-over study was conducted among type 2 diabetes mellitus patients treated with stable doses of at least 240 mg gliclazide plus 1000 mg metformin in the Out-Patient Clinic, Penang Hospital. Patients were randomised to receive either originator (Group A) or generic (Group B) glibenclamide/metformin 2.5/500 mg, two tablets twice daily for 12 weeks. After 12 weeks, Group A and Group B were switched to generic and originator, respectively, for another 12 weeks. HbA1c, pill count and hypoglycaemic episodes were measured at baseline and at 12 and 24 weeks. Results: The mean (AESD) age of the 84 patients in the study was 58.01 AE 7.87 years, and the median duration of diabetes was 10.00 years (interquartile range 7.00-16.75 years). Baseline characteristics were similar between the two groups. Mean HbA1c decreased significantly from 0 to 12 weeks in Groups A and B (À0.76% and À0.56%, respectively), but increased significantly from 12 to 24 weeks (+0.39% and +0.33%, respectively). There was no significant difference in the mean change in HbA1c between the two groups. Adherence improved significantly by 11% when patients were switched to fixed-dose glibenclamide/metformin regardless of whether it was originator or generic. There was no significant difference between originator and generic in the number of hypoglycaemic episodes (11 vs 32; p = 0.825) after switching to fixed-dose glibenclamide/metformin. Conclusion: Generic glibenclamide/metformin was therapeutically equivalent to its originator.