Alpha-glucosidase inhibitor
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'''Alpha-glucosidase inhibitors''' are oral [[anti-diabetic drug]]s used for [[diabetes mellitus type 2]] that work by preventing the digestion of carbohydrates (such as [[starch]] and [[sucrose|table sugar]]). Carbohydrates are normally converted into simple sugars ([[monosaccharide]]s) which can be absorbed through the intestine. Hence, alpha-glucosidase inhibitors reduce the impact of carbohydrates on [[blood sugar]].
==Examples and differences==
Examples of alpha-glucosidase inhibitors include:
* [[Acarbose]]- Precose
* [[Miglitol]] - Glyset
* [[Voglibose]]
Even though the drugs have a similar mechanism of action, there are subtle differences between acarbose and miglitol. Acarbose is an [[oligosaccharide]], whereas miglitol resembles a [[monosaccharide]]. Miglitol is fairly well-absorbed by the body, as opposed to acarbose. Moreover, acarbose inhibits pancreatic alpha-amylase in addition to alpha-glucosidase.
==Role in clinical use==
[[Alpha-glucosidase]] inhibitors are used to establish greater [[Diabetes management#Glycemic control|glycemic control]] over [[hyperglycemia]] in [[diabetes mellitus type 2]], particularly with regard to [[postprandial]] hyperglycemia. They may be used as monotherapy in conjunction with an appropriate [[diabetic diet]] and exercise, or they may be used in conjunction with other anti-diabetic drugs.
Alpha-glucosidase inhibitors may also be useful in patients with [[diabetes mellitus type 1]]; however, this use has not been officially approved by the [[Food and Drug Administration]].
==Mechanism of action==
Alpha-glucosidase inhibitors are [[saccharide]]s that act as [[competitive inhibitor]]s of enzymes needed to digest [[carbohydrate]]s: specifically [[alpha-glucosidase]] enzymes in the brush border of the small intestines. The membrane-bound intestinal [[alpha-glucosidase]]s hydrolyze [[oligosaccharide]]s, [[trisaccharide]]s, and [[disaccharide]]s to [[glucose]] and other [[monosaccharide]]s in the small intestine.
Acarbose also blocks pancreatic alpha-amylase in addition to inhibiting membrane-bound alpha-glucosidases. [[Pancreatic]] [[alpha-amylase]] hydrolyzes complex starches to [[oligosaccharides]] in the lumen of the small intestine.
Inhibition of these enzyme systems reduces the rate of digestion of carbohydrates. Less glucose is absorbed because the carbohydrates are not broken down into glucose molecules. In [[diabetic]] patients, the short-term effect of these drugs therapies is to decrease current blood glucose levels: the long term effect is a small reduction in [[glycosylated hemoglobin|hemoglobin <sub>A1c</sub>]] level.<ref>{{cite book |author=Samantha J. Venable; Diane S. Aschenbrenner |title=Drug Therapy In Nursing |publisher=Lippincott Williams & Wilkins |location=Hagerstwon, MD |year= |pages= |isbn=0-7817-4839-9 |oclc= |doi=}}</ref>
==Dosing==
Since alpha-glucosidase inhibitors are competitive inhibitors of the digestive enzymes, they must be taken at the start of main meals to have maximal effect. Their effects on [[blood sugar]] levels following meals will depend on the amount of complex carbohydrates in the meal.
==Side effects & precautions==
Since alpha-glucosidase inhibitors prevent the degradation of complex carbohydrates into glucose, the carbohydrates will remain in the intestine. In the [[Colon (anatomy)|colon]], bacteria will digest the complex carbohydrates, thereby causing gastrointestinal side effects such as [[flatulence]] and [[diarrhea]]. Since these effects are dose-related, it is generally advised to start with a low dose and gradually increase the dose to the desired amount.
Voglibose, in contrast to acarbose, has less of these side effects, and is hence preferred lately{{Fact|date=June 2007}}. It is also more economical compared to acarbose{{Fact|date=June 2007}}.
If a patient using an alpha-glucosidase inhibitor suffers from an episode of [[hypoglycemia]], the patient should eat something containing [[monosaccharide]]s, such as glucose tablets. Since the drug will prevent the digestion of carbohydrates, non-monosaccharide foods may not effectively reverse a hypoglycemic episode in a patient taking an alpha-glucosidase inhibitor.
==References==
<references/>
{{Oral hypoglycemics}}
[[Category:Alpha-glucosidase inhibitors]]