Smoking leads to major changes in the absorption of the newly approved inhaled insulin, Exubera, German and US researchers warn.

“These findings, which are consistent with other studies conducted to assess the effect of inhaled insulin in smokers, show that smoking greatly increases the rate and extent of absorption of Exubera,” Dr. Reinhard H. A. Becker told Reuters Health.

Becker, of Aventis Pharma Deutschland, Frankfurt, and colleagues examined the absorption profile of Exubera in 20 healthy non-diabetic active chronic smokers, who then quit smoking and finally resumed smoking. In addition, the team compared the absorption of inhaled insulin in smokers with that in 10 healthy non-smokers.

Maximum levels of insulin in the blood were significantly higher in smokers than in nonsmokers, the researchers report in the medical journal Diabetes Care. The time it took to reach peak levels was also shorter in smokers than in non-smokers.

Following smoking cessation, insulin absorption declined within 1 week and approached non-smoker levels. This was completely reversed with smoking resumption.

Thus, “Exubera should not be used in people with diabetes who choose to continue smoking,” warned Becker, because rapid changes in insulin levels can lead to excessively low blood sugar levels.

“In line with the recommendations from the FDA and EU Commission,” he concluded, “people should have stopped smoking at least 6 months prior to starting Exubera and if smoking is resumed during Exubera therapy, treatment should be discontinued immediately.”

SOURCE: Diabetes Care, February 2006.