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Thiazolidinediones (TZDs)

Thiazolidinediones (TZDs), also known as glitazones, are a type of medication that people with type 2 diabetes can use to lower blood sugar levels by reducing insulin resistance.

How do TZDs work?

TZDs work by binding to a protein in cells (called the peroxisome proliferator-activated receptor gamma, or PPAR gamma) to activate genes and create new proteins that reduce insulin resistance. Insulin resistance occurs when cells in the body don’t respond fully to insulin to take up glucose from the bloodstream to use for energy – this is one of the underlying problems of type 2 diabetes. Ultimately, TZDs help glucose enter a person’s cells.

Who uses TZDs?

TZDs are used by people with type 2 diabetes who need additional methods of lowering blood glucose beyond what metformin or other treatments can provide. However, the use of TZDs in the US and Europe has declined significantly in due to safety concerns. Discuss this risk with your healthcare professional and whether you might benefit from another glucose-lowering medication such as GLP-1 agonists or SGLT-2 inhibitors.

What are the benefits?

  • TZDs improve insulin sensitivity.

  • TZDs can be taken orally once per day, so they do not need to be injected.

  • TZDs are cheaper than newer diabetes drugs and are available in generic brands.

  • TZDs can raise HDL (“good”) cholesterol levels and lower blood pressure.

What are the drawbacks?

  • Taking TZDs can result in weight gain and edema.

  • TZDs can increase your risk heart failure and bone fractures.

Approved TZD drugs:

  • Avandia (rosiglitazone) – available in the US but not Europe

  • Actos (pioglitazone)

Last updated: August 2, 2021