A history of renal failure (unless recovered for at least  months), lactic acidosis, recurrent or severe hypoglycemia, or significant chronic obstructive lung disease; patients will not be excluded for reversible episodes of elevated creatinine due to hypovolemia
Prior history of lactic acidosis
Chronic (daily use for >  month) use of cimetidine (significant increase in metformin concentration and risk of lactic acidosis)
Iodinated contrast agents used in prior  hours (significant increase in metformin concentration and risk of lactic acidosis)
Subjects receiving metformin or other agents known to increase risk of lactic acidosis.
Patients with history of lactic or any other metabolic acidosis
Subject currently being treated with biguanides or other agents known to increase risk of lactic acidosis
Patients with history of lactic or any other metabolic acidosis
Patients with a history of chronic kidney disease or lactic acidosis
Metabolic acidosis, acute or chronic, including ketoacidosis
Prior history of lactic acidosis or metabolic acidosis
Patient has a history of lactic acidosis, chronic kidney disease or a creatinine >= . mg/dl
Patients with acute or chronic metabolic acidosis, lactic acidosis, or ketoacidosis; Note: during the study, metformin must be discontinued for  hours before and  hours after imaging involving intravenous (IV) contrast to minimize risk of lactic acidosis
Patients with plasma bicarbonate less than  mEq/L or history of lactic or any other metabolic acidosis
Subject currently being treated with biguanides or other agents known to increase risk of lactic acidosis.
Patients with history or evidence of lactic acidosis or metabolic acidosis will be excluded
A history of metabolic acidosis, including ketoacidosis or increased risk of lactic acidosis
metabolic acidosis > -  milliequivalent (mEq)/L for more than  hours,
Prior history of lactic acidosis
Patients with plasma bicarbonate less than  mEq/L or history of lactic or any other metabolic acidosis
Patients with plasma bicarbonate less than  mEq/L or history of lactic or any other metabolic acidosis
Have a prior history of lactic acidosis by self-report
History of lactic acidosis
Have a history of lactic acidosis or risk factors for lactic acidosis
Active or history of lactic acidosis, metabolic acidosis, or diabetic ketoacidosis
History of lactic acidosis as per prior medical records or provided by the patient
Metabolic acidosis, acute or chronic; acidosis will be defined a blood pH < .; acidosis will be suspected if serum bicarbonate is <  mEq/L; in such cases, venous blood pH would be checked to confirm or exclude acidosis
Patients with plasma bicarbonate less than  mEq/L or history of lactic or any other metabolic acidosis