NEW YORK (Reuters Health) – The macrolide antibiotic clarithromycin may potentiate glucocorticoid treatment in asthmatics in part by anti-inflammatory action, according to the results of a pilot study conducted by researchers from Denver.
Dr. Joseph D. Spahn, of National Jewish Medical and Research Center, and colleagues note that macrolide antibiotics have "a long history of use as glucocorticoid-sparing agents in patients with severe steroid-dependent asthma." In addition, they may also display "anti-inflammatory effects."
To examine this possible mechanism, the investigators conducted an open-label study using blood specimens obtained from seven patients with well-controlled mild to moderate asthma. The findings appear in the December issue of the Annals of Allergy, Asthma, and Immunology.
The subjects were given clarithromycin 500 mg twice daily. Blood samples drawn at baseline and at completion of the 10-day treatment period underwent lymphocyte stimulation assays.
At baseline, clarithromycin alone caused no significant suppression of T-lymphocyte activation. After treatment there was a heightened response to clarithromycin.
However, evaluation of responsiveness to dexamethasone with and without clarithromycin, showed that the combination resulted in "much greater suppression than that achieved by either agent alone." In particular, clarithromycin prompted a significant decrease in the inhibitory concentration of dexamethasone required to cause a 50% reduction in lymphocyte proliferation.
In light of these and other "provocative results," the researchers call for a larger placebo-controlled study in patients with severe, steroid-dependent asthma.
Ann Allergy Asthma Immunol 2001;87:501-505.