Thiazolidinediones for type 2 diabetes

Examples

Generic Name	Brand Name
pioglitazone	Actos
rosiglitazone	Avandia
rosiglitazone and metformin	Avandamet

Metformin is a biguanide medication. For more information, see the Medications section of the topic Type 2 Diabetes: Recently Diagnosed.

How It Works

The action of these medications in treating type 2 diabetes is not completely understood. They improve the way cells in the body respond to insulin by lowering insulin resistance. Unlike some other medications used to treat diabetes, they do not cause the pancreas to produce more insulin.

Pioglitazone may help in the treatment of high cholesterol by reducing triglycerides and increasing high-density lipoproteins (HDL) in the blood. Rosiglitazone increases high-density lipoproteins (HDL) and slightly increases low-density lipoproteins (LDL).¹ If you have high LDL, this may be a factor in selecting pioglitazone over rosiglitazone. The long-term effects of thiazolidinediones on cholesterol levels and the incidence of heart disease are not known.²

Unlike pioglitazone, rosiglitazone does not interact with certain medications, such as the antibiotic erythromycin and birth control pills.

Why It Is Used

These medications are not recommended as the first choice to lower blood sugar levels. Thiazolidinediones should be used only when other medications have failed to lower blood sugar levels into a safe range.

Pioglitazone can be used alone or in combination with sulfonylurea medicines, metformin, and insulin shots. Rosiglitazone should not be used alone or with sulfonylurea medicines unless you can't take metformin. Rosiglitazone should not be used if you are taking insulin shots.

How Well It Works

Clinical studies have shown that these medications can effectively lower blood sugar levels.¹

Side Effects

Some reported side effects of thiazolidinediones include:

• Upper respiratory infections and sinusitis.
• Headaches.
• Mild anemia.
• Retention of fluid in the body. This may lead to heart failure.
• Weight gain.
• Muscle pain.

Women who take rosiglitazone (Avandia) or pioglitazone (Actos) may increase their risk for upper arm or foot fractures.

Troglitazone (Rezulin), a thiazolidinedione that has been removed from the market in the United States and some European countries, has been shown to cause severe liver problems in a small number of people who took it. At present, the newer thiazolidinediones (rosiglitazone and pioglitazone) have not been shown to cause liver damage. However, this may still be a risk. Symptoms of liver damage include:

• Nausea, vomiting, and abdominal pain.
• Fatigue.
• Loss of appetite.
• Yellowing of the skin or the whites of the eyes (jaundice).
• Dark urine.

If you are taking one of these medications and have these symptoms, report them immediately to your doctor.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

Health Canada has announced a possible safety issue with the drug rosiglitazone (Avandia). A new study shows that people who take Avandia raise their chance of having a heart attack. They may also raise their chance of death from heart disease.

If you take Avandia, do not stop taking the medicine. Call your doctor to talk about which medicine is best for you.

People who have heart failure or are at risk for it should not use these medications. Talk to your doctor about whether you should take these medications. Notify your doctor immediately if you notice a sudden increase in your weight or experience shortness of breath or other symptoms of heart failure.

People with liver disease should not take thiazolidinediones. Children also should not take these medications, because of the risk of developing liver problems. If you are taking rosiglitazone or pioglitazone, you need to have blood tests before starting the medication, then every 2 months during the first year, and periodically thereafter to make sure your liver is not being damaged. If blood test results show liver damage, you will have to stop taking the medication.

Talk with your doctor if you want to become pregnant or are pregnant and are taking one of these medications. You may be given another medication because the use of these medications during pregnancy has not been studied.

Women who have stopped menstruating before they start taking these medications may begin menstruating again and may become pregnant.

If you are taking pioglitazone along with insulin or a sulfonylurea, which causes the pancreas to produce more insulin, you may need to take a lower dose of the insulin or sulfonylurea to prevent low blood sugar (hypoglycemia).

A new study shows that people who take rosiglitazone (Avandia) raise their chance of having a heart attack. They may also raise their chance of death from heart disease. If you take Avandia, do not stop taking the medicine. Call your doctor to talk about which medicine is best for you.

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Author:	Merrill Hayden Carrie Henley	Last Updated: November 27, 2006
Medical Review:	Adam Husney, MD - Family Medicine Caroline S. Rhoads, MD - Internal Medicine Hanan Bassyouni, MD - Endocrinology and Metabolism Matthew I. Kim, MD - Endocrinology & Metabolism
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