INTRANASAL INSULIN THERAPY - THE CLINICAL REALITIES

To evaluate metabolic control and safety parameters (hypoglycaemia fre quency and nasal mucosa physiology), 31 insulin-dependent diabetic pat ients were treated with intranasal insulin at mealtimes for 1 month an d with subcutaneous fast-acting insulin at meals for another month in an open, crossover randomized trial. During both treatment periods the patients were treated with intermediate-acting insulin at bedtime. Si x of the patients were withdrawn from the study during intranasal insu lin therapy due to metabolic dysregulation. Serum insulin concentratio ns increased more rapidly and decreased more quickly during intranasal as compared with subcutaneous insulin administration. Metabolic contr ol deteriorated, as assessed by haemoglobin A(1c) concentrations, slig htly but significantly after intranasal as compared with subcutaneous insulin therapy. The bioavailability of intranasally applied insulin w as low, since intranasal insulin doses were approximately 20 times hig her than subcutaneous doses. The frequency of hypoglycaemia was simila r during intranasal and subcutaneous insulin therapy, and nasal mucosa physiology was unaffected after intranasal insulin. We conclude that due to low bioavailability and to a high rate of therapeutic failure, intranasal insulin treatment is not a realistic alternative to subcuta neous insulin injections at the present time.