on. In elderly patients, particularly those ≥80 years of age, renal function should be monitored regularly and, generally, Glipizide and Metformin HCl Tablets should not be titrated to the maximum dose (see WARNINGS and DOSAGE AND ADMINISTRATION). Before initiation of Glipizide and Metformin HCl Tablets therapy and at least annually thereafter, renal function should be assessed and verified as normal. In patients in whom development of renal dysfunction is anticipated, renal function should be assessed more frequently and Glipizide and Metformin HCl Tablets discontinued if evidence of renal impairment is present.
Use of concomitant medications that may affect renal function or metformin disposition
Concomitant medication(s) that may affect renal function or result in significant hemodynamic change or may interfere with the disposition of metformin, such as cationic drugs that are eliminated by renal tubular secretion (see PRECAUTIONS: Drug Interactions), should be used with caution.
Radiologic studies involving the use of intravascular iodinated contrast materials (for example, intravenous urogram, intravenous cholangiography, angiography, and computed tomography (CT) scans with intravascular contrast materials)
Intravascular contrast studies with iodinated materials can lead to acute alteration of renal function and have been associated with lactic acidosis in patients receiving Metformin (see CONTRAINDICATIONS). Therefore, in patients in whom any such study is planned, Glipizide and Metformin HCl Tablets should be temporarily discontinued at the time of or prior to the procedure, and withheld for 48 hours subsequent to the procedure and reinstituted only after renal function has been reeva luated and found to be normal.
Hypoxic states
Cardiovascular collapse (shock) from whatever cause, acute congestive heart failure, acute myocardial infarction, and other conditions characterized by hypoxemia have been associated with lactic acidosis and may also cause prerenal azotemia. When such events occur in patients on Glipizide and Metformin HCl Tablets therapy, the drug should be promptly discontinued.
Surgical procedures
Glipizide and Metformin HCl Tablets therapy should be temporarily suspended for any surgical procedure (except minor procedures not associated with restricted intake of food and fluids) and should not be restarted until the patient's oral intake has resumed and renal function has been eva luated as normal.
Alcohol intake
Alcohol is known to potentiate the effect of metformin on lactate metabolism. Patients, therefore, should be warned against excessive alcohol intake, acute or chronic, while receiving Glipizide and Metformin HCl Tablets. Due to its effect on the gluconeogenic capacity of the liver, alcohol may also increase the risk of hypoglycemia.
Impaired hepatic function
Since impaired hepatic function has been associated with some cases of lactic acidosis, Glipizide and Metformin HCl Tablets should generally be avoided in patients with clinical or laboratory evidence of hepatic disease.
Vitamin B12 levels
In controlled clinical trials with metformin of 29 weeks duration, a decrease to subnormal levels of previously normal serum vitamin B12, without clinical manifestations, was observed in approximately 7% of patients. Such decrease, possibly due to interference with B12 absorption from the B12-intrinsic factor complex, is, however
