Medicine & USMLE

Thiazolidinediones (TZDs)

Diabetes Drugs
  1. Insulin Overview
  2. Rapid Acting Insulin
  3. Short Acting Insulin
  4. Intermediate Acting Insulin
  5. Long Acting Insulin
  6. Metformin
  7. Sulfonylureas
  8. Meglitinides
  9. Thiazolidinediones (TZDs)
  10. DPP-4 Inhibitors
  11. Incretin Mimetics
  12. SGLT2 Inhibitors
  13. Alpha Glucosidase Inhibitors
  14. Pramlintide


Thiazolidinediones, often abbreviated TZDs, all have a -glitazone ending, such as pioglitazone and rosiglitazone. TZDs are used to treat type 2 diabetes mellitus. They do this by decreasing glucose production in the liver, increasing insulin sensitivity, and increasing glucose uptake in cells. Side effects of TZDS include edema, increased risk of heart failure, increased risk of bladder cancer, weight gain, liver damage, and increased risk of bone fractures.

Key Points

  • Thiazolidinediones (TZDs)
    • Drug Names
      • -glitazone Ending
        • Pioglitazone (Actos)
        • Rosiglitazone (Avandia)
    • Mechanism
      • Increase insulin sensitivity
        • TZDs bind to PPAR gamma, which increases the cell’s response to insulin
        • In other words, TZDs decrease insulin resistance
      • Decrease liver glucose production
        • TZDs slow the process by which glucose is produced in the liver, called gluconeogenesis
      • Increase glucose uptake
    • Clinical Use
      • Treats Type 2 Diabetes Mellitus (DM)
        • TZDs lower blood glucose levels
    • Side Effects
      • Worsens Heart Failure
        • Contraindicated in patients with late stages of heart failure
        • Black box warning
        • Patients should report signs and symptoms of heart failure, which include shortness of breath, edema, and fatigue.
      • Causes weight gain
      • Causes edema (fluid retention)
        • This fluid retention is what leads to the worsening of heart failure and contributes to weight gain
      • Causes liver damage (hepatotoxicity)
        • Monitor the patient’s liver enzymes during treatment
      • Increases risk for bladder cancer
        • May be seen with long-term use   
      • Increases risk of bone fracture
        • May be seen with long-term use   
        • Avoid in patients with osteoporosis