What is the difference between acarbose, miglitol and voglibose?📏📏📏

Acarbose, miglitol and voglibose are commonly used clinical α-glucosidase inhibitors. Although they all belong to the same type of hypoglycemic drugs, there are some differences between them and the choice of drugs is also different.

What is the mechanism of action of α-glucosidase inhibitors?

α-glucosidase inhibitors reversibly inhibit α-glucosidase. They inhibit the degradation of disaccharides, oligosaccharides and polysaccharides to glucose and other monosaccharides. As a result, the absorption and decomposition of carbohydrates will be delayed, which will lower the patient's postprandial blood sugar.

It can be seen from the figure above that the structures of glucose and miglitol are very similar. Therefore, α-glucosidase inhibitors have good inhibitory effects on various α-glucosidases.

	Acarbose	Miglitol	Voglibose
Maltase	+	+	++
Isomaltase	+	+	+
Sucrase	+	+	++
Glucoamylase	+	+	-
α-amylase	+	+	-
Trehalase	-	+	-
Lactase	-	+	-

Since acarbose, miglitol and voglibose all have strong inhibitory effects on sucrase, sucrose or starch should not be used in hypoglycemic conditions in patients taking α-glucosidase inhibitors to correct blood sugar in patients. These foods are less effective at correcting blood sugar levels for this condition. Glucose or honey should be consumed to correct blood sugar in these patients.

What are the clinical applications of α-glucosidase inhibitors?

α-glucosidase inhibitors are indicated for patients with elevated postprandial blood glucose following a carbohydrate-based diet. Some researchers have evaluated clinical studies on patients with type 2 diabetes, and the results show that α-glucosidase inhibitors can reduce the HbA1c of patients by about 0.5% and reduce their weight. Studies have shown that acarbose can reduce the risk of developing diabetes by 25% in patients with impaired glucose tolerance within 3.3 years. Therefore, acarbose can be used to treat patients with type 2 diabetes and reduce postprandial blood glucose in patients with impaired glucose tolerance.

Drug Name	Common dosage forms
Acarbose	Oral regular-release dosage form.
	Chewable tablet.
Miglitol	Oral regular-release dosage form.
Voglibose	Oral regular-release dosage form.
Oral regular-release dosage forms include regular tablets, soft capsules, hard capsules and enteric-coated capsules.

Effects of α-glucosidase inhibitors on the liver.

Acarbose: 1 to 2% of orally administered acarbose is absorbed through the gut. In addition, digestive enzymes and intestinal bacteria will also break down some of the acarbose. These amounts add up to about 35% of the dose. High doses of acarbose may cause asymptomatic liver enzyme elevations. Therefore, monitoring of changes in liver enzymes in patients should be considered during the first 6 to 12 months of treatment. Acarbose is contraindicated in patients with severe liver disease.

Miglitol: Miglitol can be completely absorbed after oral administration of 25 mg. 100mg of miglitol is only about 50 to 70% absorbed. Miglitol is not metabolized in the body. Therefore, there is no mention of hepatotoxicity in its labelling. In addition, the incidence of rash when taking miglitol orally is about 4.3%. This rash is usually temporary.

Voglibose: After oral administration of voglibose, voglibose could not be detected in the patient's plasma and urine. However, less than 0.1% of patients will develop fulminant hepatitis, severe liver dysfunction with elevated ALT and AST, or jaundice after taking voglibose. Voglibose should be used with caution in patients with severe hepatic impairment.

What are the drug interactions of acarbose, miglitol and voglibose?

Common ground: The clinical efficacy of α-glucosidase inhibitors is suppressed by digestive enzyme preparations and intestinal adsorbents.

The difference:

1. Acarbose: The bioavailability of digoxin can be affected by acarbose. Therefore, the dose of digoxin needs to be adjusted when the two are used at the same time.
2. Miglitol: Studies have shown that when healthy people take digoxin and miglitol at the same time, the plasma concentration of miglitol will be reduced by 19 to 28%. However, in diabetic patients taking digoxin, the concentration of digoxin in their blood will not change due to the combination of miglitol. In addition, the bioavailability of ranitidine and propranolol was decreased by about 60% and 40%, respectively, by miglitol.
3. Voglibose: Its instruction manual does not mention the above interaction.

What is the dosage of acarbose, miglitol and voglibose?

Acarbose: The initial dose is 50mg three times a day, and then gradually increased to 100mg three times a day. For individual patients, the dose can be increased to 200 mg three times a day. Acarbose needs to be swallowed whole immediately before a meal or chewed with food at the beginning.

Miglitol: The general recommended initial dose is 25 mg three times a day. The recommended maintenance dose is 50 mg three times a day. Its maximum recommended dose is 100 mg three times daily. Miglitol needs to be taken at the beginning of each meal.

Voglibose: The dosage for adults is generally 0.2 mg three times a day. If the curative effect of the patient is not obvious, the dosage can be increased to 0.3mg each time. Voglibose needs to be taken orally before meals, and meals need to be taken immediately after taking the medicine.

α-glucosidase inhibitors slow the digestion and absorption of carbohydrates in the small intestine. Flatulence is caused by bacteria in the colon that interact with unabsorbed sugars. It may cause bloating, abdominal pain, and diarrhea. Therefore, α-glucosidase inhibitors need to be started with small doses. This can reduce the occurrence of gastrointestinal reactions.

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