Tolerance and effectiveness of inhaled antibiotics at standard or low doses in COPD patients with chronic Pseudomonas aeruginosa bronchial infection

To evaluate the tolerance and effectiveness of standard doses (StD) and low doses (LoD) of inhaled antibiotics (IA), in patients with chronic obstructive pulmonary disease (COPD) and chronic bronchial infection (CBI) by Pseudomonas aeruginosa (PA). Single-center, observational, retrospective, follow-up study of patients with COPD and CBI by PA treated with IA between 2012 and 2021. One year before and one after the first IA dose were analysed. 87 patients were included (86 men) with a mean FEV1(%) of 46.3%. Intolerance to IA was observed in 54 (62.1%), with a median time of 30 days (IQR: 15, 90). Only a higher FEV1(%) was associated with lower probability of intolerance (hazard ratio: 0.98, 95% confidence interval 0.97 to 0.99; p = 0.021). Seven of 15 (46.6%) patients who did not tolerate StD tolerated LoD. Those unable to tolerate LoD also had worse FEV1(%) (38.4% (SD:18.7%) versus 48.1% (SD: 16.4%); p = 0.018). Treatments lasting 6-12 months improved symptoms and reduced PA isolations (- 2.1; P < 0.001) and exacerbations (-1.7, P < 0.001). In 19 patients LoD treatment reduced exacerbations (-2.1, P = 0.003), days of hospitalization (-7.4, P = 0.036) and PA isolations (-2, P = 0.001) with clinical improvement. Antimicrobial resistance was not observed in any case receiving LoD of IA. More than half of our COPD patients treated with IA for CBI by PA presented respiratory intolerance during the first three months related to greater severity of airway obstruction. Treatment with LoD of IA appears to be an effective and safe alternative for some patients unable to tolerate StD.