The searches identified 10 trials; four are included (287 participants aged five to 39 years; maximum follow up of four years) and one is currently awaiting classification pending publication of the full trial report. Three trials compared ibuprofen to placebo (two from the same centre with some of the same participants); one trial assessed piroxicam versus three ibuprofen trials were deemed to have good or adequate methodological quality, but used various outcomes and summary measures. Reviewers considered measures of lung function, nutritional status, radiological assessment of pulmonary involvement, intravenous antibiotic usage, hospital admissions, survival and adverse effects. Combined data from the two largest ibuprofen trials showed a significantly lower annual rate of decline for lung function, percent predicted forced expiratory volume in one second mean difference (95% confidence interval to ); forced vital capacity mean difference (95% confidence interval to ); forced expiratory flow (25-75%) mean difference (95% confidence interval to ). The post-hoc analysis of data from two trials split by age showed a statistically significant slower rate of annual decline of percent predicted forced expiratory volume in one second and forced vital capacity in the ibuprofen group in younger children, mean difference % (95% confidence interval to ) and mean difference % (95% confidence interval to ) respectively. In one trial, long-term use of high-dose ibuprofen was associated with reduced intravenous antibiotic usage, improved nutritional and radiological pulmonary status. No major adverse effects were reported, but the power of the trials to identify clinically important differences in the incidence of adverse effects was did not have any concerns with regards to risk of bias for the trial comparing piroxicam to placebo. However, the trial did not report many data in a form that we could analyse in this review. No data were available for the review's primary outcome of lung function; available data for hospital admissions showed no difference between the groups. No analysable data were available for any other review outcome.