Inhaled insulin was approved by the Food and Drug Administration in 2006. A new review of the body of published research on inhaled insulin reveals positive and negative results. Keep in mind, this body of research is lean and only covers a six month window of follow-up.

Researchers examined eight studies involving 1,881 patients with type 2 diabetes to compare inhaled insulin, injected insulin and oral medications.

On the positive side, inhaled insulin worked as well as short-acting injected insulin to control blood sugar over three months. Inhaled insulin can also improve blood glucose control for type 2s who have not had good results with short-acting insulin taken on top of baseline insulin. But inhaled insulin users had more difficulty controlling low blood glucose (hypoglycemia).

For patients who had never taken any form of insulin, inhaled insulin alone was better than oral medications to control blood glucose levels at a three-month follow-up. But again, higher rates of hypoglycemia occured for patients taking oral medications plus inhaled insulin.

Researchers point out existing evidence on inhaled insulin for type 2 patients is unable to answer important clinical questions regarding patient satisfaction, inhaled insulin's effect on other diabetes complications, weight gain and one of the most important issues, long-term impact on lung function. Additionally, inhaled insulin dosing is not as precise as injected insulin, but companies are working on the problem.

Lead researcher, Dr. Jonathan Treadwell, stated the resistance of doctors and patients to inhaled insulin focuses on the concern for possible long-term lung damage. The question remains whether inhaled insulin could exacerbate existing lung problems suspected in many people with diabetes. Treadwell says it is too early know if inhaled insulin could be used as extensively as injected insulin. Here is an AP story from last March on doctor resistance to Pfizer's inhaled insulin product Exubera.

Inhaled insulin is not recommended for patients who have smoked within the past six months, have lung disease, anyone younger than 18 or experiencing an episode of hypoglycemia. Read this Newswise story in dLife.