The aim of this review was to examine changes in the use of diabetes medicines prescribed to treat type 2 diabetes in the primary care setting. Five electronic databases were searched using strict inclusion/exclusion criteria. The quality of eligible studies was appraised using the Newcastle–Ottawa Scale. Findings show the trend has been away from using sulfonylurea and towards the use of metformin. The introduction of newer drugs has not shifted treatment outcomes and glycaemic control. It was not possible to determine how clinicians make choices about the medicines they prescribe for T2DM, or what influences those choices.