Inhaled insulin: Overcoming barriers to insulin therapy?

Inhaled insulin is a new route of insulin delivery that can be used in the treatment of type 1 and type 2 diabetes. It offers an alternative and additional means of insulin administration, and has been received with particular satisfaction by patients who dislike injections. Trials indicate that inhaled insulin can be used effectively for pre-meal bolus intensification of treatment. Pre-meal inhaled insulin with Exubera® has shown faster absorption and similar duration of action to regular subcutaneous insulin with an overall similar glucodynamic effect. Although bioavailability is lower, mainly due to losses in the upper airways, this is compensated for by dose. The commonest side effect reported with inhaled insulin, as with subcutaneous insulin, was hypoglycaemia, almost a quarter of patients noted a cough which settled with continued treatment. Increased antibody titres and changes in lung function return to normal on discontinuation of inhaled insulin. Quality of life scores indicate patient preference for inhaled versus injected insulin, thus increased choice may improve adherence to treatment regimens. However, true cost:benefit analyses have to be undertaken as do studies in children, smokers and people with respiratory conditions, e.g. asthma.