The α-glucosidase inhibitors are a group of oral anti-diabetic drugs. They are usually second or third line agents and can be used in severe hyperglycaemia when other agents are contraindicated or ineffective. They are occasionally used as monotherapy in the elderly or in patients with postprandial glucose spiking.
The α-glucosidase enzyme is present in the brush border of the intestinal villi and breaks down starch into sugar. By preventing this breakdown, inhibitors prevent uptake of sugar. The weight-loss drug Orlistat has a similar effect on fats. These drugs should therefore be taken with meals. As there is no effect on insulin, they do not cause hypoglycaemia.
The increased transit of starch through the rest of the gut, its osmotic effect and its breakdown by the normal gut bacteria result in the unpleasant side effects of these drugs. These include excessive flatulence, diarrhoea and abdominal bloating.
The most commonly used α-glucosidase inhibitor is Acarbose. Miglitol may also be used. These agents are most effective with a high-starch, low sugar diet.
British National Formulary v.54
Brunton et al. Goodman & Gilman's The Pharmacological Basis of Therapeutics 11th edition.