Smith 1999.

Methods	Double‐blind, computer‐generated randomisation, symptomatic regimen. Parallel trial.
Participants	37 male, 39 female, mean age 16.3 years. 111 participants enrolled, 35 withdrawn. 76 participants in total aged 6 ‐ 18 years. PsA colonised. Group 1 (azlocillin): 33 participants (19 male) mean (SD) age 16.07 (7.4) years Group 2 (azlocillin & tobramycin): 43 participants (18 male) mean (SD) age 16.53 (6.9) years
Interventions	Azlocillin 450 mg/kg/day, 4‐hourly plus placebo vs azlocillin plus tobramycin 240 mg/m2/day, 6‐hourly, 14 days course.
Outcomes	Lung function, time to next admission, symptom scores, adverse events, bacteriology, inflammatory markers, resistant strains.
Notes	No data for symptom scores.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated randomisation balance by FVC and center.
Allocation concealment (selection bias)	Low risk	Code generated by research pharmacist at the core center.
Blinding (performance bias and detection bias) All outcomes	Low risk	Participants and clinicians blinded, serum concentrations monitored by unblinded 3rd party (research pharmacist).
Incomplete outcome data (attrition bias) All outcomes	Low risk	35 participants withdrawn (21 from azlocillin group), reasons given in a table.

CBC: complete blood count
 CXR: chest x‐ray
 ITT: intention‐to‐treat
 PsA: Pseudomonas aeruginosa