Comparison of azithromycin and co-amoxiclav in the treatment of acute tracheobronchitis and acute infectious exacerbations of chronic bronchitis in adults. Azithromycin Study Group.

Azithromycin, a broad-spectrum azalide, and co-amoxiclav were compared in a randomized, multicentre, open-label trial in 759 patients treated for acute tracheobronchitis (n = 620) or acute infectious exacerbations of chronic bronchitis (n = 139). Patients were randomized (2:1) to a 3-day regimen of two azithromycin 250 mg capsules once daily or a 5-10-day regimen of co-amoxiclav, one 625 mg tablet three times daily. Azithromycin produced a significantly higher cure rate (70.6% versus 61.1%) than co-amoxiclav (P = 0.011) and there were fewer failures (7.8% versus 13.6%) and relapses in the azithromycin-treated group, giving a higher overall response rate for azithromycin (89.7% versus 80.2%, P = 0.0003). With azithromycin, compliance was better than with co-amoxiclav and there was a significantly shorter time to improvement or cure. A higher incidence of adverse events, mostly gastrointestinal, was reported by patients taking co-amoxiclav (21.3% versus 14%, P = 0.0097), causing more patients in this group to discontinue therapy (7% versus 1.2%, P = 0.00004).