The immune-suppressant drug tacrolimus, usually used to prevent rejection of transplanted organs, can also help people who suffer from aspirin-triggered asthma, Japanese researchers report.

The finding “suggests a new therapeutic strategy for aspirin-induced asthma,” investigator Dr. Hiroto Matsuse told AMN Health.

Matsuse, at Nagasaki University School of Medicine, and colleagues note in the Journal of Allergy and Clinical Immunology that it’s unclear just why some people suffer an asthma attack if they take aspirin.

However, it has been suggested that aspirin causes a “massive release” of substances called leukotrienes into the airways, triggering constriction. Tacrolimus inhibits the production of leukotrienes, the team says, and has other properties that might be helpful for these patients.

To investigate, the researchers studied 12 aspirin-sensitive asthmatics who had undergone testing with aspirin to determine the individual dose that provoked an attack.

The participants were then given tacrolimus or an inactive placebo 2 hours before being challenged again with their threshold dose of aspirin.

Following the placebo, aspirin challenge significantly decreased lung function and increased leukotriene levels in urine. On the other hand, tacrolimus significantly inhibited airway constriction and reduced the increase in leukotriene levels.

The researchers stress that the subjects had relatively mild aspirin-induced asthma and that tacrolimus “may not inhibit aspirin attacks in patients with a more severe form.”

SOURCE: Journal of Allergy and Clinical Immunology, December 2004.