Aims/IntroductionIn treatment algorithms of type 2 diabetes mellitus in Western countries, biguanides are recommended as first‐line agents. In Japan, various oral hypoglycemic agents (OHAs) are available, but prescription patterns are unclear.Materials and MethodsData of 7,108 and 2,655 type 2 diabetes mellitus patients in study 1 and study 2, respectively, were extracted from the Medical Data Vision database (2008–2013). Cardiovascular disease history was not considered in study 1, but was in study 2. Initial choice of OHA, adherence to its use, effect on glycated hemoglobin levels for 2 years and the second choice of OHA were investigated.ResultsIn study 1, α‐glucosidase inhibitor, glinide and thiazolidinedione were preferentially medicated in relatively lower glycated hemoglobin cases compared with other OHAs. The two most prevalent first prescriptions of OHAs were biguanides and dipeptidyl peptidase‐4 inhibitors, and the greatest adherence was for α‐glucosidase inhibitors. In patients treated continuously with a single OHA for 2 years, improvement in glycated hemoglobin levels was greatest for dipeptidyl peptidase‐4 inhibitors. As a second OHA added to the first OHA during the first 2 years, dipeptidyl peptidase‐4 inhibitors were chosen most often, especially if a biguanide was the first OHA. In study 2, targeting patients with a cardiovascular disease history, a similar tendency to study 1 was observed in the first choice of OHA, adherence and the second choice of OHA.ConclusionsEven in Japanese type 2 diabetes mellitus patients, a Western algorithm seems to be respected to some degree. The OHA choice does not seem to be affected by a cardiovascular disease history.