Efficacy of Combination Therapy With Sitagliptin and Low-Dose Glimepiride in Japanese Patients With Type 2 Diabetes

BACKGROUND: We examined the effects of combination therapy with 50 mg/day of sitagliptin and low-dose glimepiride (1 mg/day) in patients with type 2 diabetes. METHODS: Twenty-six patients with poorly controlled type 2 diabetes currently taking high-dose glimepiride (≥ 2 mg/day) were enrolled in the study. The dose of glimepiride was reduced to 1 mg/day and 50 mg/day of sitagliptin was added without changing the doses of any other antihyperglycemic agents. The patients were divided into two groups: the low-dose group (2 or 3 mg glimepiride decreased to 1 mg: n = 15) and the high-dose group (4 or 6 mg glimepiride decreased to 1 mg: n = 11). RESULTS: Combination therapy significantly lowered HbA1c after 24 weeks of treatment in both groups. In the low-dose group, 8.1 ± 0.2% decreased to 7.0 ± 0.1%; in the high-dose group, 8.4 ± 0.1% decreased to 7.3 ± 0.2%. The time course of the degree of HbA1c reduction in the high-dose group was almost superimposable on that in the low-dose group. There were no changes in body weight and no hypoglycemia and in either group during the study period. In conclusion, our results suggested that the combination therapy used in the study is both well tolerated and effective. CONCLUSION: This study indicated the usefulness of dipeptidyl peptidase (DPP)-4 inhibitors in Japanese patients with type 2 diabetes, and also reinforces the importance of low doses of sulfonylurea for effective glycemic management.