Doxycycline after sinus surgery

INTERVENTION: Doxycycline 100mg tablets by mouth twice daily for 4 weeks, commencing on the morning after surgery. Patients will be asked to return any unused tablets to monitor adherence. CONDITION: Chronic rhinosinusitis; ; Chronic rhinosinusitis Respiratory ‐ Other respiratory disorders / diseases Surgery ‐ Other surgery PRIMARY OUTCOME: 22‐item Sino Nasal Outcome Tool (SNOT‐22) score[3 months post‐operative] SECONDARY OUTCOME: 22‐item Sino Nasal Outcome Tool (SNOT‐22) score[2 weeks and 12 months post‐operative] Change in sinus mucus microbial ecology assessing the resident microflora of sinus mucus using PCR to amplify microbial DNA[Intra‐operative and at 2 weeks and 3 months post‐operative] Cytokine levels in sinus mucus via swab collection and assay[Intra‐operative and at 2 weeks and 3 months post‐operative] Modified Lund Mckay Postoperative Endoscopy Score (MLMES) Reference: Snidvongs et al. Rhinology. 2013[3 months post‐operative] Patient reported adverse events including but not limited to rash, diarrhoea, vomiting, abdominal pain via documentation of verbal feedback[Entire time course over which study drug and placebo are administered] INCLUSION CRITERIA: Patient undergoing Bilateral Comprehensive Endoscopic Sinus Surgery for the treatment of chronic rhinosinusitis as defined by the European Position Statement, 2020