Prophylactic antibiotics in asthma

Macrolides are a class of antibiotics that are widely used in the treatment of various infectious diseases, including respiratory tract infections:

• evidence suggests that
  • macrolides in people with asthma may have a steroid-sparing effect (1)
  • macrolides may have an anti-inflammatory effect of this class of antibiotics, whereby macrolides seem to decrease bronchial hyperresponsiveness associated with eosinophilic inflammation (2)
    
    
• mechanism of action of macrolides in asthma:
  • have anti-inflammatory and antimicrobial properties
    • by reducing airways inflammation directly and by controlling intracellular infection, which may trigger and maintain inflammation
      • anti-inflammatory potential has been linked to their action on pro-inflammatory cytokines and chemokines causing inflammation
      • in vivo and in vitro studies of human and animal models have demonstrated that macrolides suppress the production of cytokines such as ILs (interleukins) and inhibit neutrophil adhesion to epithelial cells, the respiratory burst of neutrophils and the secretion of mucous from human airways
        
        
• a systematic review concluded (3):
  • "...macrolides were better than placebo in reducing exacerbations and may have benefits for some people in improving asthma symptoms, asthma control, asthma quality of life and some measures of lung function, but how much benefit and for whom are uncertain. Based on one well conducted study, the macrolide azithromycin may have some benefit for people with severe asthma..."

Reference:

• Nelson HS et al. A double-blind study of troleandomycin and methylprednisolone in asthmatic subjects who require daily corticosteroids. American Review of Respiratory Disease 1993;147(2):398-404
• Amayasu H et al. Clarithromycin suppress bronchial hyperresponsiveness associated with eosinophilic inflammation in patients with asthma. Annals of Allergy, Asthma and Immunology 2000;84(6):594-8.
• Undela K, Goldsmith L, Kew KM, Ferrara G. Macrolides versus placebo for chronic asthma. Cochrane Database of Systematic Reviews 2021, Issue 11. Art. No.: CD002997.