Study objective: Long-term administration of macrolide
antibiotics reduces sputum production in patients with chronic airway
diseases, probably by inhibiting airway inflammation. The objective of
the present study was to determine the acute effects of a macrolide on
airway chloride secretion and sputum production.
Methods: We first investigated the effect of erythromycin
treatment on chloride diffusion potential difference (CPD) across
tracheal mucosa in vivo. Next, we conducted a
double-blind, parallel-group study examining the effect of 7 days of
treatment with clarithromycin (400 mg/d), amoxicillin (1,500 mg/d), or
cefaclor (750 mg/d) in patients with chronic bronchitis or
bronchiectasis without apparent respiratory infection.
Results: IV administration of erythromycin decreased the
CPD of rabbit tracheal mucosa in a dose-dependent manner. Treatment of
patients with clarithromycin decreased sputum production, whereas
amoxicillin and cefaclor treatment had no effect. The percentage of
patients whose sputum decreased > 30% from baseline (responders) was
38% in the clarithromycin group, 7% in the amoxicillin group, and 0%
in the cefaclor group. During treatment with clarithromycin, the sputum
solid composition increased and chloride concentration decreased in
responders, but these changes were not observed in nonresponders.
Conclusion: Short-term administration of 14-membered
macrolide reduces chronic airway hypersecretion, presumably by
inhibiting chloride secretion and the resultant water secretion across
the airway mucosa.