Is inhaled tobramycin (Tobramycin) an alternative first-line inhaled antibiotic, after inhaled colistin (Colistin), indicated for Pseudomonas bronchiectasis according to the European Respiratory Society (ERS) guidelines?

Inhaled Tobramycin as an Alternative First-Line Therapy for Pseudomonas Bronchiectasis

Yes, inhaled tobramycin is indeed an alternative first-line inhaled antibiotic (after colistin) indicated for Pseudomonas aeruginosa infection in bronchiectasis according to European Respiratory Society (ERS) guidelines. Both the adult and pediatric ERS guidelines explicitly list tobramycin as one of the recommended inhaled antibiotics for P. aeruginosa eradication and management.

Evidence from ERS Guidelines

Eradication Therapy for New P. aeruginosa Infection

• Both the 2017 adult and 2021 pediatric ERS bronchiectasis guidelines recommend inhaled tobramycin as an alternative to colistin for P. aeruginosa eradication therapy 1
• The guidelines specifically mention "inhaled antibiotics for 4-12 weeks (e.g., colistin, tobramycin)" as part of the eradication protocol 1
• Figure 3 in both guidelines illustrates treatment pathways that include tobramycin as one of the recommended inhaled antibiotics 1

Treatment Regimens

• For adults with newly isolated P. aeruginosa, the ERS guidelines suggest three possible eradication pathways, all of which include inhaled antibiotics (colistin, tobramycin, or gentamicin) for a total duration of 3 months 1
• For children with bronchiectasis, the guidelines recommend inhaled antibiotics (colistin or tobramycin) for 4-12 weeks following oral ciprofloxacin or intravenous antibiotics 1

Clinical Evidence Supporting Tobramycin Use

• A randomized controlled trial by Orriols et al. showed that patients receiving nebulized tobramycin had better P. aeruginosa eradication rates (54% vs 29% in placebo) after 12 months 1
• This study also demonstrated longer time to P. aeruginosa recurrence and fewer exacerbations and hospital admissions in the tobramycin group 1
• A recent (2021) retrospective study showed that tobramycin inhalation therapy significantly reduced hospitalization rates (from 1.24 ± 1.36 to 0.52 ± 0.91, p=0.019) in non-cystic fibrosis bronchiectasis patients with P. aeruginosa colonization 2

Implementation Considerations

• The choice between colistin and tobramycin should consider:
  • Patient factors (adherence, tolerance, preference) 1
  • P. aeruginosa susceptibility profile 1
  • Local availability of antibiotics 1
• Inhaled antibiotics may cause bronchospasm in 10-32% of patients, with tobramycin specifically associated with increased wheeze in some studies 1, 3
• Pre-treatment with a short-acting bronchodilator and a supervised test dose with pre- and post-spirometry is recommended when initiating inhaled antibiotics 1

Common Pitfalls and Caveats

• No inhaled antibiotics have been officially approved for non-cystic fibrosis bronchiectasis in the United States or Europe, despite their inclusion in guidelines 4
• Regular sputum surveillance is necessary to identify new P. aeruginosa isolates, with a minimum recommendation of annual sputum sampling when clinically stable 1
• The ERS guidelines do not recommend attempting eradication of chronic P. aeruginosa infection that has been present for many years, as this is unlikely to be successful 1
• When using inhaled antibiotics, monitor for potential side effects and emergence of resistance 1

In conclusion, while both colistin and tobramycin are recommended as inhaled antibiotics for P. aeruginosa in bronchiectasis, the ERS guidelines do not explicitly prioritize one over the other, suggesting they are equivalent alternatives based on current evidence.