Antidiabetic agents.

Although either insulin or oral hypoglycemics may be used in conjunction with diet and exercise in the management of type II diabetes, drug therapy for type I diabetes involves only insulin. C-peptide levels can be tested to assess whether the patient has remaining pancreatic endocrine function. Patients being started on insulin for the first time should receive a single injection of an intermediate-acting insulin of "human" origin at a dose of approximately 0.5 U/kg. Thereafter, fasting, mid-morning, mid-afternoon, bedtime, and possibly early morning blood sugars should be examined periodically to determine if the insulin dose needs to be increased, decreased, split, or if the patient needs to be on a two-insulin regimen. Intensive insulin therapy has become commonplace to control plasma glucose levels in the majority of patients receiving insulin therapy. Proper patient education regarding the insulin regimen, injection techniques, blood glucose monitoring, as well as diet, exercise, and foot care are essential if the patient's diabetes is to be controlled adequately. Guidelines for "adequate" glycemic control are outlined in Table 6. Recent evidence suggests that tight control of plasma glucose levels may decrease the macrovascular complications of diabetes. Although there is also evidence to suggest that the onset of microvascular complications might be delayed with strict glycemic control, the data are conflicting. The benefits of strict control must be weighted against the problems of hypoglycemia experienced by many patients who attempt tight control of their blood glucose levels. Biguanide compounds are available in Europe, but the sulfonylureas comprise the only class of oral agents in the United States commercially available for the treatment of type II diabetes. The two generations of these drugs reflect their potency and possible side-effect profiles. Of the first-generation agents, tolbutamide and chlorpropamide are the most widely prescribed. Tolbutamide is the weakest of the sulfonylureas, possibly making it a good drug for initiating oral therapy in the elderly. Chlorpropamide is becoming a less popular agent because of its long duration of action and its increased incidence of side effects. Of the second-generation agents, glyburide offers a better dosing schedule (once daily compared with twice daily for glipizide); however, glyburide may produce a greater incidence of hypoglycemia, particularly in the elderly or in patients with significant renal impairment. There are few good studies comparing these two drugs so that recommending one over the other is difficult. Drug interactions are numerous with the first-generation drugs, but less so with the newer second-generation agents.(ABSTRACT TRUNCATED AT 400 WORDS)