Xu 2012.

Methods	Randomised double‐blind placebo‐controlled trial. Single centre.
Participants	Inclusion criteria included participants undergoing uncomplicated inpatient CF exacerbation who were colonized with Pseudomonas aeruginosa.
Interventions	Oral doxycycline (100 mg) twice a day versus placebo.
Outcomes	Primary outcomes: safety and tolerability; change in MMP‐9 activity in sputum and blood samples. Secondary outcomes: measures of inflammatory biomarkers in sputum and blood; change in lung function; sputum and blood doxycycline levels. Sputum and blood samples were collected at the beginning of hospitalization and prior to doxycycline; sputum and blood were also collected at end of hospitalization.
Notes	Randomisation was conducted by UAB Research Pharmacy. Participants were followed up 1 month after trial completion with phone call.

CF: cystic fibrosis