Q. My husband takes metformin for diabetes. Recently his nurse practitioner prescribed Actos for him to take along with the metformin. I'm mystified about why he needs both. He has never had high blood sugar when he has gone to her office for tests. Could you advise?

A. If your husband's blood sugar is not high, I'm also mystified why he would be taking these medications. I suspect there might be some miscommunication going on. Have your husband call the doctor or nurse practitioner and ask that the details be explained to you.

Here's a type 2 diabetes primer:

Normally, insulin (secreted by the pancreas) maintains proper levels of glucose (sugar) in the blood in two ways. When levels start to rise, insulin moves glucose from the blood into cells and signals the liver to cease glucose output.

Cells use glucose for energy or store it as glycogen for later use.

In type 2 diabetes, the body doesn't make enough insulin or is resistant to it.

Your husband's medications indicate he's resistant to insulin. This allows his blood glucose to remain too high, which can lead to kidney, eye, nerve, and blood vessel damage, as well as increased risk of heart attack and stroke.

Sometimes more than one medication is needed to hold down glucose levels.

Both Actos (pioglitazone) and metformin help tissues respond to the body's insulin. Additionally, metformin suppresses glucose output by the liver.

Measuring fasting plasma glucose is the preferred method for diagnosing type 2 diabetes. "Fasting" means no calories for at least eight hours.

A normal value is less than 100 mg/dL. A value of 100 to 125 is considered "pre-diabetes." A diagnosis of diabetes is made when the value is 126 or higher.

It's generally a good idea to confirm the diagnosis with a second test a week later.

Once a diagnosis is made, the goal is to keep plasma glucose levels within a certain range as follows:

Before meals: 90 to 130

After meals: less than 180

An A1c test (short for glycosylated hemoglobin A1c) is typically done every three months. It mirrors long-term glucose control. The goal for those with diabetes is an A1c value less than 7. Some guidelines recommend a lower value.

Diabetes is now considered equivalent to having heart disease, so you also want to control your blood pressure and cholesterol levels. Here are the recommended goals:

Blood pressure: less than 130/80

LDL cholesterol (the bad kind): less than 100

HDL cholesterol (the good kind): over 40

Triglycerides: less than 150

Lifestyle changes -- exercise, diet, and weight loss -- are the first choice to combat diabetes. In some cases, this may be all that's needed.

By the way, the Actos your husband takes is in the same family as Avandia (rosiglitazone). Although calling for further study, the U.S. Food and Drug Administration Aug. 14 announced that the class of diabetes drugs that includes Avandia and Actos will carry the FDA's toughest "black box" warning that the drugs are linked to an increase in heart failure.