Glimepiride strongly enhances the glucose-lowering effect in triple oral antidiabetes therapy with sitagliptin and metformin for Japanese patients with type 2 diabetes mellitus.

Background: After approval of sitagliptin and >750 mg of metformin in Japan, a triple oral antidiabetes drug (OAD) regimen including sulfonylurea, metformin, and sitagliptin was sometimes described. However, in the real world of clinical practice, the daily dose of sulfonylurea tended to be decreased according to the warning from the Japan Diabetes Society for avoiding hypoglycemia, instead of increasing the dose of metformin for maintaining hemoglobin A1c (HbA1c) levels with this regimen. This study examined the impact of either a small dose of glimepiride or a high dose of metformin on HbA1c in triple OAD therapy with sitagliptin in a 3-month, single-center, open-label, randomized controlled study.