Lack of efficacy of long-term, low-dose azithromycin in chronic rhinosinusitis: a randomized controlled trial

In persistent chronic rhinosinusitis (CRS), conventional treatment is often insufficient. Long-term, low-dose administration of macrolides has been suggested as a treatment option. The MACS (Macrolides in chronic rhinosinusitis) study is a randomized placebo-controlled trial evaluating the efficacy of azithromycin (AZM) in CRS.

We describe a group of patients with recalcitrant CRS with and without nasal polyps unresponsive to optimal medical and (in 92% also) surgical treatment. Patients were treated with AZM or placebo. AZM was given for 3 days at 500 mg during the first week, followed by 500 mg per week for the next 11 weeks. Patients were monitored until 3 months post-therapy. The assessments included Sino-Nasal Outcome Test-22 (SNOT-22), a Patient Response Rating Scale, Visual Analogue Scale (VAS), Short Form-36 (SF-36), rigid nasal endoscopy, peak nasal inspiratory flow (PNIF), Sniffin' Sticks smell tests and endoscopically guided middle meatus cultures.

Sixty patients with a median age of 49 years were included. Fifty per cent had asthma and 58% had undergone revision sinus surgery. In the SNOT-22, Patient Response Rating Scale, VAS scores and SF-36, no significant difference between the AZM and the placebo groups was demonstrated. Nasal endoscopic findings, PNIF results, smell tests and microbiology showed no relevant significant differences between the groups either.

At the investigated dose of AZM over 3 months, no significant benefit was found over placebo. Possible reasons could be disease severity in the investigated group, under-dosage of AZM and under-powering of the study. Therefore, more research is urgently required.