Acarbose

Acarbose is an example of an alpha-glucosidase enzyme inhibitor used in the treatment of non-insulin-dependent diabetes mellitus (NIDDM). It slows the conversion of polysaccharides to monosaccharides in the gut.

Use should be restricted to those who have failed to respond to diet alone and cannot tolerate conventional oral hypoglycaemic drugs, or in whom the latter class are contraindicated (1). Its role as an adjunct to other hypoglycaemics is still unclear (1).

Also NICE guidelines recommend that acarbose should be considered for a person unable to use other oral glucose-lowering medications (2).

The use of acarbose is limited by gastrointestinal side effects (3)

• there is trial evidence from a placebocontrolled study involving 1,946 patients with type 2 diabetes (who were previously enrolled in UKPDS) that compliance rates after three years were significantly lower in the group given acarbose in addition to pre-existing therapy compared with the group given placebo (39% vs. 58%, P<0.0001) (4)
  • non-compliance with acarbose was mainly due to the increased proportion of patients reporting flatulence (30% vs. 12%, P<0.00001) and diarrhoea (16% vs. 8%, P<0.0001)
• this study revealed that acarbose did improve glycaemic control over three years, irrespective of what other therapy patients were receiving
  • however, the study was not large enough to provide any information on whether acarbose reduced microvascular or macrovascular events

A more recent systematic review concluded (5):

• it is unclear whether alpha-glucosidase inhibitors influence mortality or morbidity in patients with type 2 diabetes
• these agents have a significant effect on glycemic control and insulin levels, but no statistically significant effect on lipids and body weight. However these effects are less sure when alpha-glucosidase inhibitors are used for a longer duration
• acarbose dosages higher than 50 mg TDS offer no additional effect on glycated hemoglobin but more adverse effects instead
• compared to sulphonylurea, alpha-glucosidase inhibitors lower fasting and post-load insulin levels and have an inferior profile regarding glycemic control and adverse effects

Reference:

• (1) Drug and Therapeutics Bulletin 1999; 37 (11): 84-87.
• (2)NICE (May 2008). Management of type 2 diabetes.
• (3) MeReC Briefing 2004;25:1-8.
• (4) Holman RR, Cull CA, Turner RC, et al. A randomised doubleblind trial of acarbose in type 2 diabetes shows improved glycemic control over 3 years (UK Prospective Diabetes Study 44). Diabetes Care 1999;22:960-4
• (5) van de Laar FA et al. Alpha-glucosidase inhibitors for patients with type 2 diabetes: results from a Cochrane systematic review and meta-analysis. Diabetes Care 2005;28:154-63