Drug Treatment of Type 2 Diabetes

If you have type 2 diabetes and are having a difficult time controlling your glucose with diet and exercise alone, your physician may decide to add a medication that will either increase your sensitivity to insulin, increase your production of insulin, or decrease the absorption of glucose from your gastrointestinal tract.

As discussed in chapter 1, people with type 2 diabetes typically have a decreased sensitivity to insulin. In other words, the insulin that is present in the body is not very effective at allowing glucose from the blood to pass into the cell. Medications that increase the sensitivity of the body's cells to insulin allow glucose to be used for energy by the cell by decreasing the level of blood glucose. Several forms of this medication, such as those referred to as biguanides, have a direct effect in the liver; other medications, commonly referred to as glitazones, have an effect predominantly in other tissues.

When glucose is high in the blood as a result of the cells' decreased sensitivity to insulin and the environment inside of each cell is low in glucose, the cells, particularly those in the liver, will begin a process called gluconeogenesis, which means a new generation of glucose. So even though the glucose is high in the blood, when the liver is insensitive to insulin it produces more glucose, which increases the glucose in the blood to an even higher level. The biguanides (Glucophage is a common brand name) increase the cells' sensitivity to insulin, thus allowing glucose to flow freely into the cell, which in turn decreases the glucose production in the liver. The glitazones (brand names Avandia and Actose) work similarly in other peripheral tissues.

The class of medication commonly used to treat type 2 diabetes increases the production of insulin in the pancreas. This type of medication is most effective in those with type 2 diabetes who have a lower production of insulin. The most common group in this class is referred to as sulfonylureas (some brand names are Amaryl, Diabeta, Diabinese, Dymelor, Glucotrol, Glynase, Micronase, Orinase, Tolinase). This type medication has been used for nearly half a century and has been improved, making it one of the most cost effective. Furthermore, because this type of medication increases your insulin levels, it is possible that you may experience hypoglycemia when taking them, especially when increasing your activity levels. Weight gain has also been associated with this class of medications. And again, to prevent hypoglycemia with exercise, you need to understand the symptoms and monitor your blood glucose levels when increasing your exercise duration or intensity. The newer drugs in this class of stimulators of insulin secretion (including Amaryl, Diabeta, Glucotrol, Glynase, and Micronase) have a quicker onset and a short duration, which may help lessen complications related to hypoglycemia and weight gain.

There is currently one other class of oral medication that can be used to decrease the blood glucose. These medications (acarbose, brand names Prandase and Precose; and miglitol, brand name Glyset) work by decreasing the absorption of carbohydrates from the gastrointestinal tract. The medications inhibit a crucial step in the breakdown of carbohydrates before they can be absorbed through the intestine into the bloodstream. However, because these medications need to be taken at the beginning of each meal, and common side effects are gas production and flatulence, these are used to a lesser extent than the three classes of drugs described previously.

People with type 2 diabetes who are having difficulty controlling glucose levels with exercise, diet, and one (or a combination) of oral medications may need to take insulin in a similar manner to those with type 1 diabetes. Frequent glucose monitoring is important here as well.