From the Research
For asthma exacerbations suspected to be complicated by bacterial infection, azithromycin is often recommended as the first-line antibiotic, given its effectiveness against common respiratory pathogens and anti-inflammatory properties, as supported by the most recent and highest quality study 1. The typical adult dosage is 500 mg on the first day, followed by 250 mg daily for 4 additional days (5-day course total). For children, the dosage is weight-based, typically 10 mg/kg on day 1 (maximum 500 mg) followed by 5 mg/kg (maximum 250 mg) for 4 more days. Alternatives include amoxicillin-clavulanate (875/125 mg twice daily for 5-7 days for adults) or doxycycline (100 mg twice daily for 5-7 days) for patients with penicillin allergies (except in children under 8 years and pregnant women). Some key points to consider when prescribing antibiotics for asthma exacerbations include:
- Antibiotics should only be prescribed when there are clear signs of bacterial infection such as purulent sputum, fever, elevated white blood cell count, or infiltrates on chest X-ray.
- Unnecessary antibiotic use can lead to resistance and side effects.
- The rationale for choosing azithromycin includes its effectiveness against common respiratory pathogens like Streptococcus pneumoniae, Haemophilus influenzae, and atypical bacteria, plus its anti-inflammatory properties that may provide additional benefit in asthma, as demonstrated in a randomised, double-blind, placebo-controlled trial 1.
- Long-term use of azithromycin may reduce Haemophilus influenzae load and improve asthma quality of life, but it also increases the risk of macrolide resistance, as shown in a study published in 2019 2.
- Other studies have highlighted the potential role of bacterial infections in asthma exacerbations, including the involvement of Streptococcus pneumoniae, Hemophilus influenzae, and Moraxella catarrhalis, as well as atypical bacteria like C. pneumoniae and M. pneumoniae 3, 4.