Abstract: We included three trials examining pulmonary exacerbations (171 participants) and two trials examining long-term therapy (85 participants). We regarded the most important outcomes as quality of life and lung function. The analysis did not identify any statistically significant difference between oral anti-pseudomonal antibiotics and other treatments for these outcome measures for either pulmonary exacerbations or long-term treatment. One of the included trials reported significantly better lung function when treating a pulmonary exacerbation with ciprofloxacin when compared with intravenous treatment; however, our analysis did not confirm this finding. We found no evidence of difference between oral anti-pseudomonal antibiotics and other treatments regarding adverse events or development of antibiotic resistance, but trials were not adequately powered to detect this. None of the studies had a low risk of bias from blinding which may have an impact particularly on subjective outcomes such as quality of life. The risk of bias for other criteria could not be clearly stated across the studies. We found no conclusive evidence that an oral anti-pseudomonal antibiotic regimen is more or less effective than an alternative treatment for either pulmonary exacerbations or long-term treatment of chronic infection with P. aeruginosa. Until results of adequately-powered future trials are available, treatment needs to be selected on a pragmatic basis, based upon any available non-randomised evidence, the clinical circumstances of the individual, the known effectiveness of drugs against local strains and upon individual preference.

Plain-language summary: We included five trials with 256 participants. Three trials included people experiencing a flare up of disease (171 participants) and two trials looked at long-term therapy (85 participants). We found no conclusive evidence to show that oral antibiotics were more or less effective than an alternative treatment for either flare ups of disease or long-term treatment of chronic infection with Pseudomonas aeruginosa. One of the trials with volunteers being treated for a flare up of disease reported significantly better lung function when using ciprofloxacin compared with intravenous treatment; but we did not agree with this finding when we analysed the same data. We did not find any evidence of differences between oral antibiotics and other treatments in terms of adverse events or the development of antibiotic resistance, but we do note that the trials were not designed to detect such differences. Until the results of large trials are available, people should choose their treatment on a practical basis, basing decisions on any available evidence, their clinical circumstances, the known effectiveness of drugs against local strains of the bug and individual preference. The evidence we found was limited. The trials were very different in terms of design, drugs used, length of treatment and follow up and the outcomes measured. We judged the trials to be at different risks of bias, but we did not think any of them had a low risk of bias from blinding, which might affect the results of subjective outcomes like quality of life.