Hypersensitivity. Significant renal insufficiency including intrinsic renal disease & renal hypoperfusion, unstable or acute CHF/MI at risk of hypoperfusion & hypoxemia; dehydration, sepsis, impaired hepatic function. Monitor renal function regularly & vit B12
level annually. Avoid excessive alcohol intake, in concomitant w/ hypoglycemic agents, or drugs that may affect renal function, alter hemodynamics or interfere w/ metformin disposition, & intravascular contrast studies w/ iodinated materials. Pregnancy & lactation. Childn <18 yr. Elderly.