Chlorpropamide is not recommended because older patients are at increased risk of hyponatremia and because the drug's prolonged duration of action is dangerous if toxicity or hypoglycemia occurs. Metformin, a biguanide excreted by the kidney, increases peripheral tissue sensitivity to insulin and can be effective in older patients alone or in combination with sulfonylureas. However, long-term efficacy and safety in older patients is not well established. Risk of lactic acidosis, a rare but serious complication, increases with the degree of renal impairment and the patient's age. Troglitazone, which can be used with insulin or oral hypoglycemics, sensitizes peripheral tissue to insulin's effects.
Older patients appear to tolerate it well.
However, concern about hepatotoxicity makes it a reserve drug. Acarbose, administered with food, reduces postprandial glucose elevations and, in combination with other hypoglycemics, can help improve blood sugar control in some patients. GI intolerance may be a problem. Some data indicate that the clearance of salicylate, oxaprozin, and naproxen is decreased in older patients. Such drugs can reduce the risk of peptic ulcer formation.