Biguanides, TZDs Flashcards
The most commonly used Biguanide is:
Metformin (Glucophage)
What is Metformin’s MOA?
*Decreases hepatic glucose production
Enhances insulin rc binding
Increases glucose utilization
Decreases insulin resistance
How is Metformin taken and excreted?
PO
Renally excreted, unchanged
AE of Metformin:
GI distress: N/D, metallic taste
Lactic acidosis (rare but life-threatening)
Reduced GI absorption of vit B12 leading to megaloblastic anemia (rare)
What is an absolute CI to the use of Metformin?
Patients with renal dysfunction per Cr clearance (<60ml/min)
Women: Scr >1.4mg/dL
Men: Scr >1.5mg/dL
In what scenario is it recommended that patients discontinue use of metformin?
Prior to and for 48hrs after IV contrast (to avoid increase metformin levels secondary to renal failure)
Thiazolidinediones (TZDs), Pioglitazone (Actos) and Rosiglitazone (Avandia) MOA:
Improves insulin sensitivity
*Stimulates rc on cell surfaces that affect insulin action
Reduces hepatic glucose production
Requires the presence of insulin for effect
How are TZDs, Pioglitazone (Actos) and Rosiglitazone (Avandia) taken and metabolized?
PO
Hepatically metabolized
How can metformin affect weight?
No weight gain or potential weight loss
What do both Metformin, Pioglitazone (Actos) and Rosiglitazone (Avandia) rarely cause?
Hypoglycemia
Common AE of TZDs: Pioglitazone (Actos) and Rosiglitazone (Avandia)
Edema (peripheral)
Weight gain (water retention, upreg of fat storage)
Hepatotoxicity (monitor transaminases, jaundice)
What boxed warning do TZDs: Pioglitazone (Actos) and Rosiglitazone (Avandia) carry?
Heart failure
MI (Rosiglitazone only)
What is specific to the use of the TZD Rosiglitazone (Avandia)?
Only used for patients who cannot achieve adequate glycemic control with other medications
Prescribers must enroll patients in the REMS program (Risk Evaluation and Mitigation Strategy program)
