Repaglinide in combination therapy

Type 2 diabetes mellitus (T2DM) is a progressive disorder requiring increasingly aggressive treatment to achieve and maintain target blood glucose concentrations in the presence of deteriorating insulin secretion and increasing insulin resistance. Diet and lifestyle modification are often sufficient initially; however, most patients eventually require pharmacological intervention. With disease progression, monotherapy becomes less effective, so combination therapy is required, using drugs with complementary modes of action to maximise glycaemic control. The prandial glucose regulator repaglinide has been studied in combination with metformin (an inhibitor of hepatic glucose production), neutral protamine Hagedorn (NPH)-insulin (which has a long duration of effect, but at the risk of early hypoglycaemia and late hyperglycaemia in the dosing interval) and three thiazolidinediones (TZDs--troglitazone, rosiglitazone and pioglitazone, which stimulate nuclear receptors to increase insulin sensitivity and reduce insulin resistance) in patients whose diabetes was inadequately controlled by previous monotherapy or combination therapy. The combination of repaglinide and metformin resulted in reduced fasting plasma glucose concentrations (by 2.2 mmol/l) and HbA1c (by 1.4%). Combination therapy with repaglinide and bedtime NPH-insulin resulted in reductions in fasting plasma glucose (by 5.4 mmol/l) and HbA1c (by 0.7%). The combination of repaglinide and each TZD also resulted in consistent decreases in fasting plasma glucose concentrations and HbA1c. No severe hypoglycaemic episodes were reported in the three studies. In conclusion, repaglinide has additive, and often synergistic, effects on glycaemic control when given in combination regimens and should be a valuable option in the management of patients with T2DM.