The impact of pharmacotherapy on weight management in type 2 diabetes

Today, obesity is the most important modifiable risk factor for type 2 diabetes. An excess of body fat is associated with a deterioration of glucose utilisation and promotes the development of type 2 diabetes, particularly in those with a genetic predisposition for the disease. It is also well established that a reduction of excess body fat improves insulin sensitivity and can prevent the conversion to diabetes. In those with overt diabetes, weight loss usually ameliorates glycaemic control and associated metabolic disturbances. Among the pharmacological agents that are used for the treatment of type 2 diabetes only metformin has a weak weight-lowering activity and is considered as the drug of choice for adjunct pharmacotherapy in obese diabetic subjects. A few studies also suggest that acarbose can induce a modest weight reduction in such patients. In contrast, sulphonylurea and insulin treatment is frequently accompanied by substantial weight gain which should be taken into consideration when these drugs are used. Another approach to improve metabolic control in obese type 2 diabetic patients is the use of weight-lowering agents. The new serotonin and noradrenaline reuptake inhibitor sibutramine promotes weight loss which subsequently leads to improved glycaemic control. Orlistat, a lipase inhibitor, is also able to ameliorate metabolic control in such patients due to its weight-lowering potential. As obesity remains a therapeutic challenge in most type 2 diabetic subjects, weight management drugs may represent an alternative or supplement to antidiabetic agents. Moreover, weight management agents have the advantage that they have additional favourable effects on associated cardiovascular risk factors.