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.