General

The goal of insulin therapy for patients with diabetes is to provide coverage that most closely resembles endogenous insulin production and results in the best glycemic control without hypoglycemia. Although daytime control of hyperglycemia may be accomplished with bolus doses of rapid-acting insulin analogs, elevations in fasting glucose may remain a problem. If fasting blood glucose levels remain elevated, the basal insulin dose (intermediate or long-acting) may have to be adjusted.

Most insulins used today are recombinant DNA human insulins. Produced through genetic engineering, synthetic human insulin is "manufactured" by yeast or nonpathogenic E. coli. In recent years, pharmaceutical companies have developed several new types and formulations of insulin.

Different insulins are distinguished by how quickly they are absorbed, the time and length of peak activity, and overall duration of action. Onset, peak, and duration of action times are approximate and vary according to individual factors such as injection site, blood supply, concurrent illnesses, lifestyle, and exercise level. These factors can vary from patient to patient and can vary in any patient from day to day.

There are 5 kinds of insulins: rapid-acting, short-acting, intermediate-acting, long-acting, and combination insulins.