type-2 diabetes

For people with type 2 diabetes, metformin can help to lower blood glucose and reduce insulin resistance.

Metformin lowers blood glucose primarily by reducing glucose production in the liver. Metformin also lowers insulin resistance in muscles and fat cells. Some people experience a slight weight loss during metformin therapy. Metformin (Glucophage, Glucophage XR) is the only prescribed medication in a class of drugs called biguanides.

• Metformin is often used in combination therapy and three combination medications are available. Glucovance contains metformin and glyburide, a sulfonylurea. Metaglip contains metformin and glipizide, a sulfonylurea. Avandamet contains metformin and rosiglitazone, an insulin sensitizer. Although metformin alone does not increase the risk of hypoglycemia, combination therapy with a sulfonylurea does increase this risk.

• Metformin may cause diarrhea or an upset stomach in some people. However, this side effect often goes away in time and may be improved by taking the drug with food. Another approach to reducing digestive side effects is to begin therapy with a low dose and gradually titrate up, as tolerated, to an effective dose.

• Rarely, metformin may cause lactic acidosis, a dangerous, potentially fatal buildup of lactic acid in the blood. For this reason, metformin is not indicated in some people, including those with kidney problems, liver disease, and those taking medications for heart failure. People who use metformin are advised not to drink alcohol, which increases the risk of lactic acidosis. Before beginning metformin therapy, the physician may recommend checking kidney function with a creatinine test.

For people with type 2 diabetes, sulfonylureas can help to lower blood glucose, but care must be taken to prevent hypoglycemia.

Sulfonylureas lower blood glucose by stimulating the pancreas to release insulin. These drugs work only in people whose pancreatic beta cells are still able to make insulin. Prescribed brands are Amaryl (glimepiride), DiaBeta, Glynase, Micronase (glyburide), Glucotrol, and Glucotrol XL (glipizide). A first-generation sulfonylurea, Diabinese (chlorpropamide), is available but no longer widely prescribed.

• Sulfonylureas increase the risk of hypoglycemia, especially if a person skips a meal, drinks too much alcohol, or engages in physical activity that is more strenuous than usual. People who take sulfonylureas should watch for hypoglycemic symptoms and be prepared to treat hypoglycemic episodes, if they occur.

• Some people are allergic to sulfa drugs and need to avoid sulfonylureas. In these situations, another diabetes medication may be prescribed.