Alpha-glucosidase inhibitors (AGIs) are antidiabetic agents used to lower glucose (blood sugar) in patients with type 2 diabetes. These drugs block enzymes in the digestive tract from breaking down complex carbohydrates from food into glucose. This slows the absorption of sugars into the small intestine and bloodstream, keeping glucose levels lower throughout the day.  

These medications can be prescribed when meal planning, weight loss and exercise alone are not effective in controlling type 2 diabetes. AGIs are especially helpful for patients whose blood glucose levels are slightly above normal. They may not be as helpful for those whose diabetes is more severe, unless they are used in combination with another antidiabetic agent or insulin.

Alpha-glucosidase inhibitors can also benefit those who have high blood glucose right after they eat, a condition known as postprandial hyperglycemia. By slowing the rate at which complex carbohydrates are broken down into sugars in the digestive tract, these drugs lengthen the digestive process. This prevents these sugars from rushing into the bloodstream and causing an unhealthy rise in blood glucose levels.

Other antidiabetic agents, including sulfonylureas and biguanides, and insulin sometimes are prescribed in combination with AGIs to help increase the effectiveness of this therapy. After adding an AGI to their treatment regimen, people who take insulin are usually able to lower their insulin dosage, as advised by their physician. The primary side effects of AGIS are gastrointestinal, such as gas and diarrhea, and they may not be advised for some patients, such as those with digestive disorders.

AGIs are also being studied as a possible treatment for heart disease, a common complication in diabetic individuals.

Alpha-glucosidase inhibitors (AGIs) are one of the groups of antidiabetic agents that can be used, along with exercise and diet, to help control glucose (blood sugar) in patients with type 2 diabetes.

AGIs slow the rate at which complex carbohydrates are broken down into sugars in the digestive tract and therefore lengthen the digestive process. This prevents these sugars from rushing into the bloodstream and causing an unhealthy rise in blood glucose levels. Post-meal blood glucose levels are an important aspect of diabetes management.

Normally, about 20 minutes after a person eats, food enters the small intestine. Enzymes break down proteins, fats and dietary starches and turn them into glucose. This glucose is then absorbed from the small intestine into the bloodstream.

The absorption process occurs fastest in the top third of the small intestine. AGIs target certain enzymes and keep them from breaking down some of the ingested complex carbohydrates (e.g. breads, potatoes, pasta). Some sugars, including fruit sugars, also are not yet broken down at this point.

The carbohydrates, proteins and fats that are not digested in the top third of the small intestine continue to travel down the small intestine and are digested when they reach the lower part not affected by the alpha-glucosidase inhibitor.  

AGIs should be taken with the first bite of a meal. They do not work if taken more than 10 minutes after a patient has begun to eat. Unlike many other antidiabetic agents, AGIs do not cause the pancreas to produce more insulin. As a result, they do not trigger low blood glucose (hypoglycemia) unless they are used in combination with insulin or an insulin-producing antidiabetic agent. Rapid-acting insulin and AGIs should not be used together because the risk of hypoglycemia may increase.

Alpha-glucosidase inhibitors do not cause weight gain, which is a problem frequently associated with many other antidiabetic agents. People with digestive problems should discuss the common gastrointestinal side effects, such as bloating and gas, with their physician.

Scientists are studying AGIs as a possible treatment for heart disease, the leading cause of death for people with diabetes. Postprandrial (after-meal) high blood glucose (hyperglycemia) as a characteristic of impaired glucose tolerance (prediabetes) is recognized as a risk factor for coronary artery disease. In a study involving 100 hospitals, Japanese researchers are recruiting 3,000 prediabetic individuals with history of heart attack to assess whether AGIs can reduce the recurrence of heart attack. However, this major study is not scheduled for completion until 2009. 

Alpha-glucosidase inhibitors include:

• Acarbose (Glucobay, Prandase, Precose)
• Miglitol (Glyset)
• Voglibose (Basen, Volix)

Alpha-glucosidase inhibitors are typically taken two to three times a day at the beginning of meals. Dosages are usually low to start and are gradually increased depending on the patient’s tolerance level.

Alpha-glucosidase inhibitors (AGIs) can cause gastrointestinal side effects and may not be the optimal medication choice for patients with a history of conditions related to those areas. In addition, high doses may cause reversible liver damage. Common side effects of AGIs include:

• Abdominal bloating
• Flatulence
• Diarrhea

The severity of these symptoms can often be reduced by decreasing the amount of carbohydrates in the patient’s diet. The likelihood of side effects can also be lowered by starting at a low dose of an AGI and gradually increasing the dosage.

Low glucose (blood sugar) can occur in patients who take an AGI in combination with another drug, such as an additional antidiabetic agent or insulin. Physicians often recommend treating low glucose (hypoglycemia) by taking a glucose tablet or glucose gel. However, because AGIs delay the intestinal digestive process, sugars, fruits and fruit juices may not raise blood glucose quickly enough in patients using these medications.

Women are generally advised not to take antidiabetic agents such as alpha-glucosidase inhibitors during pregnancy. The amount of insulin a woman needs changes during and after pregnancy, and physicians often recommend insulin injections. Other options for treatment include include diet and exercise.

Pregnant women must maintain proper glucose (blood sugar) levels, as high blood glucose (hyperglycemia) can cause birth defects or excessive weight gain in babies.  Women who are pregnant or thinking of becoming pregnant should consult their physician.

Some antidiabetic agents pass into human breast milk. Nursing mothers should consult with a physician before taking these medicines.

Preparing questions in advance can help patients have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following  questions about alpha-glucosidase inhibitors (AGIs):

1. What are the advantages and disadvantages of alpha-glucosidase inhibitors for me compared to other antidiabetic agents, insulin and other treatments for type 2 diabetes?
   
   
2. Is it safe for me to use AGIs if I’m prone to diabetic ketoacidosis or if I have gastroparesis, other gastrointestinal conditions or liver disease?
   
   
3. How do these medications work? How do they affect my digestive system?
   
   
4. What is the name of my medication and its dosage? Do I need to take it at the start of every meal?
   
   
5. What side effects might I experience?
   
   
6. Can AGIs affect my other medications?
   
   
7. Are these medications safe for pregnant women, breastfeeding women or children?
   
   
8. Will a combination of oral diabetes drug or the addition of insulin be a good option for me?
   
   
9. What should I do if I miss a dose? Is it OK to take my AGI after I start eating?
   
   
10. How do I know if the drug is or is not working, if my need for insulin is declining or if my dosage needs to be changed?
    
    
11. How should I notify you if I want to stop taking the drug or change the dosage?
    
    
12. Can improvements in diet and exercise reduce or eliminate my need for this drug? If so, how will we monitor these changes?
    
    
13. Is there any news about AGIs as a possible treatment or preventive measure for diabetic heart disease?