Metformin-glibenclamide versus metformin plus rosiglitazone in patients with type 2 diabetes inadequately controlled on metformin monotherapy

Aim: This double-blind study evaluated the efficacy and safety of metformin-glibenclamide tablets vs. metformin plus rosiglitazone therapy in patients with type 2 diabetes inadequately controlled on metformin monotherapy. Subjects and methods: After an open-label, metformin lead-in phase, 318 patients were randomly assigned to treatment based on metformin-glibenclamide 500/2.5 mg tablets (initial daily dose 1000/5 mg) or metformin 500 mg plus rosiglitazone 4 mg (initial daily dose 1000-2000 mg + 4 mg, depending on previous treatment) for 24 weeks. Doses were titrated to achieve the therapeutic glycaemic target. The primary efficacy variable was the change in HbA(1C). Results: At week 24, metformin-glibenclamide tablets resulted in significantly greater reductions in HbA(1C) (-1.5%) and fasting plasma glucose [-2.6 mmol/l (-46 mg/dl)] than metformin plus rosiglitazone [-1.1%, p < 0.001; -2 mmol/l (-36 mg/dl), p = 0.03]. More patients receiving metformin-glibenclamide attained HbA(1C) < 7.0% than did those in the metformin plus rosiglitazone group (60 vs. 47%) and had fasting plasma glucose levels < 7 mmol/l (< 126 mg/dl) by week 24 (34 vs. 25%). Both treatments were well tolerated. Frequency of adverse gastrointestinal events was comparable between groups. Four per cent of patients receiving metformin-glibenclamide withdrew because of symptomatic hypoglycaemia contrasted with 3% of patients receiving metformin plus rosiglitazone who withdrew because of persistent hyperglycaemia. Hypoglycaemic events were mild or moderate in intensity and were easily self-managed. Conclusions: Metformin-glibenclamide tablets resulted in significantly greater reductions in HbA(1C) and fasting plasma glucose compared with metformin plus rosiglitazone in patients with type 2 diabetes inadequately controlled on metformin monotherapy.