Metformin is a commonly used oral agent for patients with noninsulin dependent diabetes mellitus. It should not be used if certain contraindications are present.


Class of drugs: biguanide


Primary hazard: lactic acidosis


Conditions associated with lactic acidosis in a patient treated with metformin (all contraindications for its use):

(1) renal dysfunction (including use of nephrotoxic agents)

(2) liver disease (including excessive alcohol use)

(3) metabolic acidosis

(4) hypoxemia (which may be associated with respiratory or metabolic acidosis)

(5) moderate to severe congestive heart failure

(6) serious illness (medical or surgical condition requiring hospitalization)


Renal function should be carefully monitored. Elderly patients may show renal impairment despite a "low" serum creatinine concentration.


Nephrotoxic agents include aminoglycosides, vancomyin and iodinated contrast agents used in imaging.


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