Metformin: a safe and effective treatment in the management of NIDDM.

The oral antihyperglycemic drug metformin has a unique mechanism of action and controls glycemia in both obese and normal-weight NIDDM patients without inducing hypoglycemia, insulin stimulation or hyperinsulinemia. Metformin used in combination with sulfonylureas has a synergistic effect in lowering fasting and postprandial glucose and hemoglobin A1c levels, and improving the lipid profile. Metformin does not increase lactate production from skeletal muscle and has little clinically significant effect on vitamin B12 and folic acid absorption. Lactic acidosis associated with metformin use is extremely rare (reported incidence of 0.03/1,000 patient-years exposure) and has occurred predominantly in patients for whom the drug was contraindicated. Observance of prescribing guidelines will greatly minimize risk, since risk factors have been identified. Metformin can be safely used in the elderly, provided prescribing precautions are followed. Dosing in the elderly should be conservative, with dose adjustment designed to achieve normal blood sugar levels.