CLINICAL EFFICACY OF ACARBOSE IN DIABETES-MELLITUS - A CRITICAL-REVIEW OF CONTROLLED TRIALS

Acarbose, an a-glucosidase inhibitor, is a new antihyperglycaemic agen t which has been proposed as add-on therapy in Type 2 diabetic patient s not well-controlled with diet alone, sulphonylurea, metformin or ins ulin, and in Type 1 diabetic patients with large meal-related plasma g lucose excursions. Numerous controlled studies investigating the clini cal effects of acarbose in Type 2 diabetes versus either placebo or, m ore rarely, versus a reference drug (sulphonylurea or metformin) have been published during the last 10 years. All placebo-controlled studie s have demonstrated the superiority of acarbose, at a dose of 150-600 mg/day, in decreasing fasting and postprandial glucose levels as well as HbA(1c) concentrations (mean decrease of 0.7%), whether acarbose wa s given as first-line therapy in diet-treated diabetic patients or in combination in individuals already receiving a sulphonylurea, metformi n or insulin. Only a few controlled studies have compared the effects of acarbose with those of either sulphonylurea or metformin, yielding controversial results. In Type 1 diabetic patients, a small reduction of HbA(1c) levels was also reported after addition of acarbose to insu lin therapy, which in some cases allowed a slight reduction of daily i nsulin needs. All these favourable biological effects occurred without exposing the patient to hypoglycaemia or weight gain. A few studies h ave also reported favourable effects on postprandial lipid profile and some other vascular risk factors. However, it is not clear whether th e extra cost of acarhose, when compared to that of older oral antidiab etic agents, is justified since no study has yet demonstrated its pote ntial benefit on the complications and long-term prognosis of diabetic patients.