Miglitol, a new alpha-glucosidase inhibitor

Miglitol (Bay m 1099, Bayer) is a second generation alpha-glucosidase inhibitor. It is a derivative of 1-desoxynojirimycin, and binds reversibly to the brushborder alpha-glucosidase enzymes. In contrast to its parent drug (acarbose, Bay g 5421, Bayer), miglitol is almost completely absorbed in the small intestine. It has to be taken with each main meal, and through its effect on carbohydrate digestion it blunts the postprandial blood glucose increase. Miglitol has no or a very small effect on fasting blood glucose levels. The blood-glucose lowering effects of miglitol in patients with Type 2 diabetes are lower than those of the frequently-used sulphonylurea compounds. Long-term studies show that a moderate average reduction of HbA1c of 0.3-0.7% point from baseline can be achieved. An advantage over sulphonylurea is the effect on serum insulin levels: miglitol therapy leads to slightly lower postprandial levels of serum insulin, whereas chronic sulphonylurea treatment usually increases serum insulin levels. This insulin-sparing effect may, in theory, lead to a lesser weight gain or even no weight gain and reduced risk of hypoglycaemia during chronic treatment. Long-term experience in Type 1 diabetic patients is limited. Similarly, miglitol may lead to reduced postprandial glucose excursions, slightly reduced insulin requirements and perhaps, as a consequence, a lower risk of hypoglycaemia. More long-term data are needed to fully assess to the clinical use of miglitol in these patients.