Thiazolidinedione (AKA:TZDs or glitazones) 


Brand Name (Generic Name)

Actos (pioglitazone)
Avandia (rosiglitazone)

Note: Troglitazone (Rezulin) was withdrawn from the market in March 2000.


 In June 2011, the FDA warned that use of Actos for more than 1 year may be associated with an increased risk of bladder cancer. The FDA recommended that people receiving treatment for bladder cancer should not take Actos, and Actos should be used with caution in people with a history of bladder cancer. This warning also applies to the combination diabetes pills containing pioglitazone—Actoplus Met, Actoplus Met XR, and Duetact.

In September 2010, the FDA announced that access to Avandia would be restricted because of studies linking Avandia to an increased risk of cardiovascular events, such as heart attacks. In May 2011, the FDA announced new restrictions on the use and distribution of Avandia and combination diabetes pills containing rosiglitazone.

After November 18, 2011, Avandia and the combination diabetes pills Avandamet and Avandaryl will no longer be available through retail pharmacies. Health care providers and patients must enroll in a special program in order to prescribe and receive these medicines.


What are thiazolidinediones?

The TZDs (some call them "glitazones") are a family of medications that work by helping to treat one of the main problems in type 2 diabetes and that is "insulin resistance". People with type 2 diabetes can be resistant to their own insulin so that it will not keep blood sugars in the normal range. This medicine makes the muscle and fat tissues of the body more sensitive to the insulin and therefore lowers blood sugar. Both pioglitazone and rosiglitazone are very effective at reducing blood sugar. There are some concerns however about their association with heart problems. The use of rosiglitazone was restricted by the Food and Drug Administration (FDA) some time ago but some of those restrictions have now been lifted. The use of Actos has been associated with bladder cancer, and both Actos and Avandia may increase fractures in women.

The conflicting news about Avandia (rosiglitazone) but not Actos (pioglitazone):

Due to the results of a large study from 2007 it was at first thought that people who took rosiglitazone had a higher incidence of heart attacks. The results of other studies did not show those same results so in 2013 the FDA lifted some of the restrictions allowing health care providers to use the drug.

Who can take them?

Carefully selected adults with type 2 diabetes can take them and they can be combined with some of the other diabetes medicines.

Who should not take them?

They are not made to treat people with type 1, and should be avoided by those with diabetic ketoacidosis. Since they can cause congestive heart failure or make it worse they should not be prescribed for anyone at risk for that condition and other serious heart conditions. People with liver problems may not be able to take them.

Please read the accompanying FDA approved medication guides for pioglitazone and rosiglitazone for a complete list of precautions.

What dosage can I take and how should I take it?

The doses ranges are 15-45 mg once daily for Actos and 4 mg to 8 mg daily for Avandia. Both are taken orally.

What are the most common side effects of pioglitazone or rosiglitazone?
• Fluid retention and swelling
• Weight gain
• Shortness of breath
• Upper respiratory infections
• Headache
• There are other potential side effects to these medicines listed in the accompanying medication guide

What else should you know before taking Actos (pioglitazone or Avandia (rosiglitazone)?

Please read the information contained in the accompanying medication guide before taking one of these medicines.

Reviewed by James A. Bennett 5/14

Last Modified Date: June 09, 2014

All content on is created and reviewed in compliance with our editorial policy.

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by Brenda Bell
As I mentioned in an earlier post, one of the benefits that made it cost-effective for me to go with the real healthcare (HSA) plan rather than the phony (HRA) plan is that my company is now covering "preventative" medicines at $0 copay. The formulary for these, as stated by CVS/Caremark (my pharmacy benefits provider), covers all test strips, lancets, and control solutions. I dutifully get my doctor to write up prescriptions for all of my testing needs, submit...
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