Effect of Glyburide-metformin Combination Tablet in Patients with Type 2 Diabetes

Background: To evaluate the efficacy and safety of glyburide/metformin combined tablet compared to glyburide or metformin alone in patients with type 2 diabetes.

Methods: In this 16-week, multicenter, randomized, double-blind, 4-arm and parallel clinical trial study, 100 patients with type 2 diabetes mellitus were recruited and 76 patients were available for statistical analysis at the end of the study. After 1 week of placebo washout period, eligible patients were randomly assigned into 1 of 4 treatment groups: glyburide 5 mg b.i.d.; metformin 500 mg b.i.d.; glyburide/metformin 2.5 mg/500 mg b.i.d.; or glyburide/metformin 5.0 mg/500 mg b.i.d. The doses were titrated every 2 weeks to a maximum of 4 tablets per day if the patients fasting plasma glucose (FPG) still exceeded 140 mg/dL. Efficacy was evaluated by the changes from baseline in glycosylated hemoglobin (HbA1c) and FPG at week 16. Adverse events were recorded and summarized by treatment group.

Results: At week 16, patients who received glyburide/metformin 2.5 mg/500 mg or 5.0 mg/500 mg tablets had greater reductions in FPG (all p<0.001) compared with glyburide or metformin monotherapy. Patients who took glyburide/ metformin 2.5 mg/500 mg tablet and glyburide/metformin 5.0 mg/500 mg tablet had significant decreases in HbA1c (both p<0.0125). Furthermore, treatment with glyburide/metformin 2.5 mg/500 mg resulted in significantly greater reduction in HbA1c compared to glyburide or metformin (-1.77%, p<0.001 and -1.34%, p=0.002), and treatment with glyburide/metformin 5.0 mg/500 mg resulted in significant lowering of HbA1c compared to glyburide or metformin alone (-1.73%, p<0.001 and -1.30%, p=0.005). Both the glyburide/metformin 2.5 mg/500 mg and glyburide/metformin 5.0 mg/500 mg combination therapy groups experienced fewer gastrointestinal adverse events than the metformin monotherapy group.

Conclusion: Both glyburide/metformin 2.5 mg/500 mg and glyburide/metformin 5.0 mg/500 mg combination therapy were efficacious and well tolerated in the treatment of Chinese patients with type 2 diabetes mellitus.