Oral diabetes medications -- diabetes pills -- help control blood sugar levels in people whose bodies still produce some insulin (the majority of people with type 2 diabetes). These diabetes drugs are usually prescribed to people with type 2 diabetes along with recommendations for making specific dietary changes and getting regular exercise. Several of these drugs are often used in combination to achieve optimal blood sugar control.
Remember that people with type 2 diabetes tend to have two problems that lead to increased sugar (glucose) in the bloodstream:
They don't make enough insulin to move glucose into cells where it belongs.
The body's cells become "resistant" to insulin (insulin resistance), meaning they don't take in glucose as well as they should.
In time, people with type 2 diabetes develop what's called "beta-cell failure." This means that the cells in the pancreas that make insulin no longer are able to release insulin in response to high blood sugar levels. Therefore, these people often require insulin injections, either in combination with their diabetes pills, or just insulin alone to manage their diabetes.
Diabetes pills are grouped in categories based on type. There are several categories of diabetes pills -- each works differently.
Sulfonylureas. These diabetes pills lower blood sugar by stimulating the pancreas to release more insulin. The first drugs of this type that were developed -- Dymelor (acetohexamide), Diabinese (chlorpropamide), Orinase (tolbutamide), and Tolinase (tolazamide) -- are not as widely used since they tend to be less potent and shorter-acting drugs than the newer sulfonylureas. They include Glucotrol (glipizide), Glucotrol XL (extended release), DiaBeta (glyburide), Micronase (glyburide), Glynase PresTab (glyburide), and Amaryl (glimepiride). These drugs can cause a decrease in the hemoglobin A1c (HbA1c) of up to 1%-2%.
Biguanides. These diabetes pills improve insulin's ability to move sugar into cells especially into the muscle cells. They also prevent the liver from releasing stored sugar. Biguanides should not be used in people who have kidney damage or heart failure because of the risk of precipitating a severe build up of acid (called lactic acidosis) in these patients. Biguanides can decrease the HbA1c 1%-2%. An example includes metformin (Glucophage, Glucophage XR, Riomet, Fortamet, and Glumetza).
Thiazolidinediones. These diabetes pills improve insulin's effectiveness (improving insulin resistance) in muscle and in fat tissue. They lower the amount of sugar released by the liver and make fat cells more sensitive to the effects of insulin. Actos (pioglitazone) and Avandia (rosiglitazone) are the two drugs of this class. A decrease in the HbA1c of 1%-2% can be seen with this class of oral diabetes medications. These drugs may take a few weeks before they have an effect in lowering blood sugar. They should be used with caution in people with heart failure. In fact, the FDA has restricted Avandia for use in new patients only if they can't control their blood sugar on other medications and are unable to take Actos. Current users can continue Avandia if they choose to do so. All patients using Avandia must review and fully understand the cardiovascular risks.