Antidiabetic agents are drugs that treat type 2 diabetes by lowering glucose (blood sugar) levels in patients. During physical exercise, the muscles use glucose as energy. When diet and exercise control glucose, the patient does not require medications. In addition to meal planning, physical activity and weight loss, medications may be prescribed if those methods by themselves cannot control a patient's type 2 diabetes.

Type 2 diabetes is a condition of abnormally elevated blood glucose levels. Typically, this is because muscle and fat cells in the body are resistant to absorbing glucose. As a result, glucose remains trapped in the bloodstream instead of entering the cells and providing the body with energy. Over time in type 2 diabetes the pancreas produces less insulin, the hormone that moves glucose from the blood into the cells. This results in insulin deficiency and is the other major contributing cause of elevated blood glucose (hyperglycemia).

There are two sources of the glucose found in the body: foods consumed by the individual, and sugar produced in the liver converted from stored body fats, proteins and glycogen.

Antidiabetic agents work by either:

• Limiting the amount of glucose that gets into the bloodstream
  
  
• Encouraging the movement of glucose from the bloodstream to the cells

According to the U.S. Centers for Disease Control and Prevention (CDC), 11.6 million adults with diabetes report taking some type of medication to control their condition. Of these adults, 7.8 million reported taking only oral antidiabetic agents, 2.1 million reported taking only insulin, and 1.7 million reported taking both. These figures are from 2003 and had not been updated as of December 2007. However, the number of people taking antidiabetic agents has likely risen because the incidence of diabetes has been soaring. Between 2002 and 2005 alone, the number of children taking antidiabetic agents doubled.

Managing type 2 diabetes with antidiabetic agents can provide short-term and long-term health benefits. These include:

• Short-term
  
  
• • Feeling healthy and more energetic
    
    
  • Preventing symptoms related to high blood glucose (hyperglycemia), such as excessive thirst, blurry vision, excessive weight loss or weight gain.
    
    
  • Preventing consequences of poorly controlled glucose, such as diabetic ketoacidosis, hyperosmolar hyperglycemic nonketotic syndrome (HHNS) and diabetic coma
    
    
• Long-term
  
  
• • Reducing odds of developing cardiovascular conditions, eye diseases (such as diabetic retinopathy and glaucoma), kidney disease (diabetic nephropathy), nerve damage (diabetic neuropathy), sexual dysfunction, foot conditions, skin problems and gum disease
    
    
  • Improving cholesterol and triglyceride levels
    

Diabetes treatments are designed to maintain blood glucose levels within a range that is considered normal and healthy. This is less than 110 milligrams per deciliter (mg/dL) during fasting periods and under 140 mg/dL after meals, according to the American Diabetes Association (ADA). Antidiabetic agents do not work for everyone with type 2 diabetes. Most people will experience a drop in their blood glucose level, but not everyone will experience a decrease to normal, healthy levels.

The effectiveness of oral antidiabetic therapy is lower for those who have had type 2 diabetes for more than 10 years or who take more than 20 units of insulin a day. In some cases, the pills work initially but lose their effectiveness after five to seven years of treatment. Antidiabetic agents are generally not effective in very thin people.

Antidiabetic agents are most effective in treating type 2 diabetes when they are used as part of a comprehensive physician-prescribed management plan. This plan typically provides for an appropriate diet, along with exercise, weight loss, glucose monitoring, regular medical care and a sick-day plan. The benefits of antidiabetic agents may be compromised if patients do not take these other steps to improve their well-being.

In addition to antidiabetic agents, medications are being developed to treat or prevent diabetic complications of the kidneys, nerves and eyes.

Furthermore, people with type 2 diabetes or prediabetes are frequently prescribed medication to treat diabetic conditions and risk factors such as high blood pressure, unhealthy cholesterol levels (hyperlipidemia) and obesity. Diabetic patients may also be prescribed glucagon, a hormonal drug that can be injected in case of severe hypoglycemia or insulin shock.

Some companies market herbal preparations as medications for diabetes. These are not regulated by the U.S. Food and Drug Administration and may contain various quantities of beneficial, ineffective or harmful ingredients. Patients are advised not to use them without approval by their physician.