Metformin (Glumetza, Glucophage, Fortamet):
- Mechanism: Decreases hepatic glucose production and peripheral glucose utilization, decreases intestinal glucose absorption (these are reasons it leads to weight loss)
- Side effects: Can cause lactic acidosis and is contraindicated if eGFR <30 (do not start at eGFR 30–45). Hold it at the time of iodinated contrast if eGFR is 30–60 and restart after 48 hours if eGFR is stable. The old "creatinine >1.5" cutoff is outdated (FDA 2016; ADA).
Sulfonylureas - Glyburide (Glynase), Glipizide (Glucotrol, Glucotrol XL), Glimepiride (Amaryl):
- Mechanism: Stimulates pancreatic beta-cell insulin release (insulin secretagogue)
- Side effects: Causes hypoglycemia and weight gain
Thiazolidinediones - Pioglitazone (Actos) and Rosiglitazone (Avandia):
- Mechanism: Increases insulin sensitivity in peripheral receptor site adipose and muscle has no effect on pancreatic beta cells
- Side effects: Can cause fluid retention and edema. Cardiovascular toxicity with Avandia.
α-Glucosidase inhibitors - Acarbose (Precose) and Glyset (Miglitol):
- Mechanism: Delays intestinal glucose absorption
- Side effects: May cause increased LFTs and hepatitis, diarrhea, flatulence
Meglitinides - Repaglinide (Prandin) and Nateglinide (Starlix):
- Mechanism: Stimulates pancreatic beta-cell insulin release
- Side effects: May cause hypoglycemia
GLP-1 Agonists - Exenatide (Bydureon, Byetta):
- Mechanism: Lowers blood sugar by mimicking incretin - causes insulin secretion and decreased glucagon and delays gastric emptying
- Side effects: May cause hypoglycemia. Caution if gastroparesis
DDP-4 Inhibitors - Sitagliptin (Januvia):
- Mechanism: Dipeptidyl peptidase inhibition - inhibits degradation of GLP-1 so more circulating GLP-1
- Side effects: May cause pancreatitis and renal failure
SGLT2 Inhibitor - Canagliflozin (Invokana or Sulisent):
- Mechanism: SGLT2 inhibition lowers renal glucose threshold, which results in increased urinary glucose excretion
- Side effects: hypoglycemia and urinary tract infections
Read more: Diabetes Mellitus Type 2
