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September 19, 2002

Inhaled Insulin

Question from Highland, Illinois, USA:

I have just completed a diabetes study, and they indicated another study was available using an inhaler. What are the pros and cons of using insulin inhalers?


From: DTeam Staff

Since inhaled insulin is still experimental, we have a lot to learn about it. So far, the pros seem to be that you do not have to inject it, which many people who inject insulin daily welcome. As far as the cons, the device is certainly much larger than a vial and syringe or insulin pen, and it requires some cleaning and a filter change.

The big question is whether this method of delivering insulin will be effective in people with respiratory problems such as people with asthma and smokers. Only time and further study will tell. The good news is that there are more and more choices available to people who require insulin.

Additional comments from Dr. Donough O’Brien:

It has been known for some years that insulin given by inhaler can control blood glucose levels in people with diabetes, but at the same time the only real ‘pro’ for this approach is that it avoids the rather minimal discomfort of injection with ultrafine needles. Some of the disadvantages are that the inhaler itself may be somewhat cumbersome and that precise dosage for people who are carb counting and adjusting dose for pre-meal blood sugar is more difficult. Also, the biological efficiency is only around 20%, meaning that it takes about five times as much inhaled insulin to match the subcutaneous dose and that this will inevitably effect cost. There have been reports too, though I have not seen formal reports, that long term use of inhaled insulin may produce harmful effects in the lungs, although this has been circumvented by using a specially modified insulin that when given by a nebuliser is absorbed by the mucosa of the mouth. So far as I know, it is not yet possible to give long acting insulin by nebuliser. The study that you are considering may be aimed at res

Additional comments from Dr. Stuart Brink:

Insulin inhalers are a relatively new way to deliver insulin. Usually just fast acting insulin (similar to Humalog and NovoLog) but without any injection.

So, benefits seem to be no injections. Potential downside is that you still need some basal insulin and this is not yet available via inhalers — so injections are still needed either with glargine or some combination of other longer acting insulins, e.g., NPH or Lantus (insulin glargine), etc. You should discuss all this directly with the study leaders who can tell you the details. Other potential downside includes problems or irritation of the lungs from inhaling insulin. We do not yet know if this is a problem or how big a problem it may be but studies are currently underway to try to answer such a question.

Additional comments from Dr. David Schwartz:

I am very much in favor of clinical trials! And I support the use of clinical trials of inhaled insulins.

However, I will share my belief and concerns that the current inhaled insulin trials will not lead to an inhaled insulin on the market anytime soon and that I doubt that the current inhaled insulin trials will replace injectable insulin. Why?

Because they are not yet practical. An inhaler for an asthmatic fits in the palm of your hand and can be placed in a pocket or purse. The current inhaled insulin devices that I have seen are not small and indeed are cumbersome. In addition, they will only provide short-acting insulin, currently, and not provide a long-lasting insulin. Some preliminary evidence has suggested pulmonary issues with inhaled insulin.

So, clinical trials should continue and I applaud you for be willing to participate. Hopefully these trials will lead to a real breakthrough!