MSRA-0500

A 52-year-old woman with a body mass index (BMI) of 32 was diagnosed with type 2 diabetes mellitus during a routine check-up six months ago. Despite being advised about a low-energy, weight-reducing diet and exercise, she has not followed through with these recommendations and her postprandial blood glucose concentration is 13.8 mmol/l (reference range <11.1 mmol/l). What would be the drug of choice in this case?