Prandial Insulin: Is Inhaled Enough?

The low proportion of patients achieving glycemic targets is well documented for both type 1 and type 2 diabetes. Postprandial glucose levels are often not monitored but contribute significantly to total glycemic burden. Prandial rapid-acting insulin analogues were introduced to address some of these problems but still do not provide a physiologic insulin replacement. Inhaled prandial insulins have been developed to free patients from multiple mealtime injections and make intensive insulin regimens more acceptable. Several inhaled formulations of prandial insulin are in development but differ significantly with respect to inhaler characteristics and pharmacokinetic profiles. This brief review summarizes the properties of the new prandial inhaled insulins and discusses how postprandial glycemic control is dependent not only on the insulin dose, but also on the pharmacokinetic characteristics of insulin delivery. There is no antihyperglycemic agent with a glucose-lowering effect superior to that of insulin; new prandial products that improve coordination between insulin availability and meal absorption and are more acceptable to patients may increase the proportion of diabetic patients achieving and maintaining glycemic targets. Drug Dev Res 69:138–142, 2008. r2008 Wiley-Liss, Inc.