Often the plan begins with monotherapy, which is one blood-glucose-lowering medicine in addition to a healthy lifestyle. If this doesn’t achieve the desired result, adding one or more additional medicines (combination therapy) may be considered. Combination therapy may involve taking two or more individual pills, or it may be achieved with one of the newer combination pills, which have two drugs in one pill.
Research has shown that most of the oral diabetes medicines currently on the market lower glycosylated hemoglobin (HbA1c) approximately 1% to 2%. The HbA1c test is an indicator of average blood glucose control over the previous 2–3 months. The American Diabetes Association currently advocates an HbA1c reading lower than 7% for most people with diabetes. The American Academy of Clinical Endocrinologists recommends an HbA1c value below 6.5%. You and your health-care provider should agree on a target that is right for you. Higher HbA1c levels are associated with the development of diabetes complications.
In general, certain classes of drugs, including the sulfonylureas, meglitinides, d-phenylalanine derivatives, and biguanides, are more potent in lowering blood glucose than are others, such as the thiazolidinediones or alpha-glucosidase inhibitors when used as monotherapy. (See “Effectiveness of Oral Medicines” for a comparison.) However, there are limits to how much of any one drug can be taken. When a maximal dose of one drug isn’t enough to keep blood glucose levels in the desired range, adding a drug from a different class can lower blood glucose further.
Insulin injections are another option for treating Type 2 diabetes and may eventually be necessary due to its progressive nature. Many physicians recommend starting insulin when three oral medicines are not effective at keeping blood glucose under control. Insulin may either be added to the current regimen of pills or used in place of one or more of the oral medicines a person has been taking.
Type 2 diabetes involves several problems in metabolism, and oral medicines have been developed to provide solutions to each one. Six distinct classes of oral drugs are now available for the treatment of Type 2 diabetes. “Oral Diabetes Medicines at a Glance” summarizes the important characteristics of each class. Each class has a different mechanism of action, which means that each contributes to blood glucose control in a different way.
Alpha-glucosidase inhibitors. This class of drugs, which includes acarbose (brand name Precose) and miglitol (Glyset), acts by inhibiting the breakdown and subsequent absorption of carbohydrates from the gut following meals, so it is most effective in controlling postprandial (after-meal) elevations in blood glucose.
Hypoglycemia (low blood glucose) generally does not occur when one of these pills is taken as monotherapy, but it can occur when one or the other is taken in combination with a blood-glucose-lowering drug that can cause hypoglycemia. It’s important to note that because of the carbohydrate-blocking effect of alpha-glucosidase inhibitors, some traditional treatments for low blood glucose, such as fruit juice, aren’t as effective at raising blood glucose as they normally would be. Sources of pure glucose, such as tablets or gel, are recommended. Gastrointestinal side effects such as abdominal discomfort, bloating, flatulence, and diarrhea may occur when using an alpha-glucosidase inhibitor.
Also in this article:
to view Oral Diabetes Medicines at a Glance and Effectiveness of Oral Medicines