A rational approach to drug therapy of type 2 diabetes mellitus

Several new pharmacological agents have recently been developed to optimise the management of type 2 (non-insulin-dependent) diabetes mellitus. The aim of this article is to briefly review the various therapeutic agents available for management of patients with type 2 diabetes mellitus and to suggest a potential approach to drug selection. There are three general therapeutic modalities relevant to diabetes care. The first modality is lifestyle adjustments aimed at improving endogenous insulin sensitivity or insulin effect. This can be achieved by increased physical activity and bodyweight reduction with diet and behavioural modification, and the use of pharmacological agents or surgery. This first modality is not discussed in depth in this article. The second modality involves increasing insulin availability by the administration of exogenous insulin, insulin analogues, sulphonylureas and the new insulin secretagogue, repaglinide. The most frequently encountered adverse effect of these agents is hypoglycaemia. Bodyweight gain can also be a concern, especially in patients who are obese. The association between hyperinsulinaemia and premature atherosclerosis is still a debatable question. The third modality consists of agents such as biguanides and thiazolidinediones which enhance insulin sensitivity, or agents that decrease insulin requirements like the alpha-glucosidase inhibitors. Type 2 diabetes mellitus is a heterogeneous disease with multiple underlying pathophysiological processes. Therapy should be individualised based on the degree of hyperglycaemia, hyperinsulinaemia or insulin deficiency. In addition, several factors have to be considered when prescribing a specific therapeutic agent. These factors include efficacy, safety, affordability and ease of administration.