If you could inhale insulin, wouldn’t it be an advantage over taking the hormone by injection? Could be a good idea, eliminating the slight discomfort of a tiny needle stick a couple of times a day, but would it really be worth it? In 2006 the FDA finally approved the inhaled insulin product, Exubera by Pfizer, but the inhaler used with the product was large and awkward. Because of the unpopularity of the product it was withdrawn. But now a new inhaler has been introduced with faster acting insulin, and has won new FDA approval. Analysts predict that the new product could earn $2 billion a year by 2010 with worldwide sales. Some doctors, however, warn that the risks of Eubera to the lungs have not been thoroughly tested. Although insulin by inhalation appears to work no better than insulin by injection, using the formulation and new mode of administration could take years before clinical experience is sufficient to declare that breathing insulin is safe to lung tissue. In clinical trials, Exubera caused some reduction in patient’s ability to breathe.
Human lungs contain about 300 million tiny air sacs where gas exchange takes place-air in, carbon dioxide out. Transporting gases efficiently is why it took over tens of millions of years for the lungs to evolve from fish gills. So far as I know, these air sacs or alveoli, were never told they might have to transport a insulin, a protein molecule that is 4,000 times heavier than a simple elemental gas like oxygen. But never worry, the Food and Drug Administration is recommending that lung function should be checked before starting Exubera and every six to twelve months thereafter. Common sense suggests that it could take another ten to twenty years or longer before we really know what inhaled insulin does to those tiny lung sacs. My humble guess is that it won’t help your breathing.
Let’s not be too exuberant about Exubera too soon-unless you hold stock in Pfizer.