Metformin should be temporarily discontinued in patients undergoing radiologic studies involving intravascular administration of iodinated contrast media, because use of such products may result in acute renal dysfunction.
Patients with renal impairment should not be given metformin. In patients with advanced age, metformin should be carefully titrated to establish the minimum dose for adequate glycemic effect, because aging is associated with reduced renal function. In those at least 80 years of age, renal function should be monitored regularly.
Alcohol is known to potentiate the effect of metformin on lactate metabolism.
Metformin should be avoided in patients with evidence of hepatic disease, since impaired hepatic function has been associated with lactic acidosis.
Metformin is not recommended for use in pregnancy and in pediatric patients. Dosage of metformin should be titrated in patients with advanced age. Elderly, debilitated and malnourished patients should not be given to the maximum dose. Monitoring of renal function is necessary to prevent lactic acidosis, particularly in the elderly.