A study was conducted by Quattrin et al to study the effect of inhaled insulin in comparison to subcutaneous insulin in patients with diabetes. The study group was administered inhaled insulin along with subcutaneous injections. On the other hand, the control group was administered subcutaneous injections only. The fasting and the post-prandial blood sugar levels dropped faster in type 1 diabetes patients who were administered inhaled insulin compared to those administered injections.
In individuals suffering from type 2 diabetes mellitus inhaled insulin seemed to be more effective compared to conventional insulin (Wollmer, 2007). Studies have shown that the patient acceptance and compliance levels with regards to inhaled insulin are much better compared to injections. In one particular study conducted, the patients preferred inhaled insulin compared to any other therapy (as high as 35%).
Insulin administered by inhaling may also work when the patient is sleeping, as small amount may remain on the lung mucosa, leading to slow absorption of the drug (Medscape, 2007 & Wollmer, 2007). Insulin is a drug that may act as a growth-promoting factor. When insulin is inhaled, it would be getting deposited in the membrane of the air sacs leading to the development of side effects. Currently, the results of long-term study are not available regards the effects of inhaled insulin.
Studies up to 4 years in duration have been conducted. Short-term studies have demonstrated no negative impact on the alveolar mucosa. The local defense mechanism of the lungs may get altered. Antibodies may be produced against insulin, which is higher than the subcutaneous administration (demonstrated through studies conducted on patients who received inhaled insulin in comparison to those administered subcutaneous injections).
Some of the common side effects that developed included cough (of moderate severity), reduction in the diffusing capacity of carbon monoxide, allergic reactions, insulin resistance, etc. Cough may develop due to the osmotic effect of the insulin powder on the alveolar mucosa (Medscape, 2007).
References:
Medscape Today (2007), Patient Acceptance and Compliance, Retrieved on October 2, 2007.