Are My Meds Wearing Off?
I am 63 and have had type 2 diabetes for 13 years. I take metformin and glipizide. My morning readings have been 150 to 180 mg/dl the past few weeks, and I cannot get them down. Is the effect of these drugs going away? Name Withheld
Belinda Childs, ARNP, MN, BC-ADM, CDE, responds:
Type 2 diabetes is a progressive disease, and over time, the body is less able to produce insulin. As your body's needs change, additional treatments may be needed.
Lifestyle considerations are important, too. Has there been a change in your meal plan, the timing of your meals, or your physical activity? For example, eating later in the evening can cause an increase in fasting blood glucose levels in the morning.
People with type 2 diabetes often start to need to take insulin to maintain near-normal blood glucose levels. There are also a range of oral and injected medications for type 2.
The two medications you are taking address three abnormalities of type 2 diabetes. Metformin, a biguanide, both reduces the amount of glucose made by the liver and increases the body's response to insulin. Glipizide, a sulfonylurea, increases the release of insulin from the cells in the pancreas that produce it.
Scientists have learned that other defects, besides insulin resistance and insulin deficiency, contribute to high blood glucose levels. A number of medications treat these defects, including thiazolidinediones (TZDs), incretin mimetics, and DPP-4 inhibitors. Pioglitazone (Actos) is a TZD that improves insulin resistance, especially in fat cells. It can be used with metformin and glipizide.
Medications known as alpha-glucosidase inhibitors delay the absorption of carbohydrates, lowering blood glucose. These drugs (acarbose and miglitol) aren't often used in the United States.
Incretin mimetics lower blood glucose by increasing the insulin release from the pancreas and also by preventing the body from releasing glucagon (which raises blood glucose). They slow the stomach's emptying after eating, too, which may help one feel full sooner and eat less. These medications, which are given by injection, include exenatide (Byetta) and liraglutide (Victoza).
DPP-4 inhibitors have similar effects, but they are taken in pill form and do not slow stomach emptying. They include sitagliptin (Januvia), saxagliptin (Onglyza), and linagliptin (Tradjenta).
Type 2 diabetes is a complex disease. The good news is that there are now many options for treating it, and discoveries keep adding to the treatments available. You'll want to review all the options with your diabetes care team.