Sulphonylureas acarbose combinations

There are three conditions for the clinical use of metformin as a glucose-lowering agent in patients with NIDDM (1) as a primary drug, (2) in combination with other oral hypoglycaemic agents such as sulphonylureas and acarbose, and (3) together with insulin after secondary sulphonylurea failure. 

Acarbose is used in diabetes in addition to other therapeutic regimes in connection with diet. Its clinical usefulness was demonstrated (Hanefeld et al., 1991) but its extent is a matter of controversy. However, a diet is preferable in Type-II diabetes. There are some studies which show the usefulness of its combination with sulphonylureas. Considerable individual variation is noted in the response to acarbose (Reaven et al., 1990). The use of acarbose in patients with NIDDM not well controlled by sulphonylureas appears to have significant clinical benefit (Raptis et al., 1982). One study suggests that it is not an effective substitute for sulphonylureas in non-obese Type-II diabetes uncontrolled by diet alone (Buchanan et al., 1988). 

For a review, see Sachse etal. (1982). Combining acarbose with sulphonylurea or metformin or insulin may lead to hypoglycaemia, although acarbose itself will not produce hypoglycaemia (doses have to be corrected). The effect of acarbose may be reduced by antacids, cholestyramine, pancreatic enzymes and adsorbants. Plasma levels of vitamin B6 increased, and vitamin A concentrations decreased with acarbose (Couet et al., 1989). 

The combination of acarbose and sulphonylureas is mainly used in patients with secondary sulphonylurea failure. Rosak (1990) reported a lowering of fasting blood glucose by 42 mg per 100 ml in diabetics treated with acarbose and sulphonylureas versus 14 mg per 100 ml with only sulphonylureas. Postprandial blood glucose was decreased by 57 mg per 100 ml, while sulphonylureas alone produced an increase of 4 mg per 100 ml in secondary sulphonylurea failure. 

The combination of sulphonylureas and acarbose (3 x 100 mg) versus sulphonylureas and phenformin (75 mg) was tested for 3 months by Pagano and Cavallo-Perin (1990), who could not find any significant difference between the two treatments as far as blood glucose, plasma insulin and HbA] were concerned. However, there was a 20% increase in plasma lactate in the biguanide group and no variation in the acarbose patients. 

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