There were during the year 2001 several publications in the medical literature on the use of inhaled insulin in Type 1 diabetes patients (Lancet 337:331-335.2001) and in type 2 patients (Ann.Int.Med 134:242-244.2001)
Just after the release of this article the newspapers, magazines etc wrote about the inhaled insulin awaking the hope for many actual insulin users.
Spite the fact that the studies with inhaled insulin already start several years ago the first patients will complete 5 years of follow up in the end of year 2003.
- Only rapid or short acting insulin can be used to be inhaled that will make necessary to continue using at least one or twice a day insulin subcutaneously in order to maintain the glucose levels between meals. Regular insulin when is inhaled has a similar action as the short acting insulin but with slightly longer duration and similar number of hypoglycemic episodes.
- When all the safety studies will end the inhaled insulin will be marketed but if it happens to soon many doubts will still remain unanswered. The use of big amount of insulin is needed for every meal because the low bioavailabilty of the inhaled insulin. The normal insulin dose for a meal in an adult patient with diabetes is 4-5 mg (every mg of insulin contains 26 Units of insulin) meaning that for each meal more than 100 Units of insulin are used.
- Until now is unknown what consequences in the long run will have the use of such a supraphisiologycal of insulin given directly into the lungs but if the lung is affected then the consequences will even worse than the inconveniences caused by the daily insulin shots.
- Some drawbacks were already described as cough in as many as 11% of the patients although in the most of the case was mild and there were no changes in pulmonary functional test.
- Other unsolved questions are:
• Degree of patient satisfaction after longer period of inhaled insulin use is unknown.
• Degree of insulin absorption if the patient coughs when or just after inhaling insulin.
To conclude, I think that someday it may be useful for some type two patients or for type 1 as recreational or special occasion insulin but surely is too early to throw away all the insulin syringes.