The combination of insulin and oral hypoglycaemic drugs: a continuous challenge.

A large number of studies have demonstrated the efficacy and usefulness of combining insulin and sulfonylurea therapy in Type 2 diabetic patients with secondary therapeutic failure. Better glycaemic profiles and/or decreased insulin needs, which are shown to persist after a maximum of 5 years, have been reported in diabetic patients on combination therapy. Residual beta-cell function appears to be a prerequisite for a favourable effect of combined therapy since the diabetics who continued to benefit from this were those whose C-peptide levels (both fasting and stimulated) remained greater than baseline. The concept of combined therapy might not be confined to sulfonylurea: the biguanide, metformin, has been found useful in obese diabetic patients with secondary failure. The combination of insulin with other new promising drugs or triple associations (insulin+sulfonylurea+biguanide) are also worth considering.