An open comparative study of azithromycin versus cefaclor in the treatment of patients with upper respiratory tract infections.

Azithromycin and cefaclor were compared for the treatment of acute otitis media, streptococcal pharyngitis/tonsillitis, or sinusitis in an open multicentre study conducted in 530 adults. At the end of therapy (day 11-15), 228/245 (93%) patients treated with azithromycin 500 mg once daily for 3 days and 233/241 (97%) treated with cefaclor 250 mg given three times daily for 10 days were considered to have responded satisfactorily (cured or improved). In bacteriologically evaluable patients with pharyngitis/ tonsillitis, Streptococcus pyogenes was eradicated in 116/117 (99%) azithromycin- and in 115/119 (97%) cefaclor-treated patients at day 11-15; one patient in each group had become reinfected after initial eradication of the pathogen. When followed up on day 25-30, S. pyogenes infection had recurred in 5/105 (5%) azithromycin and 4/108 (3%) cefaclor patients who had responded satisfactorily at day 11-15, and whose baseline pathogen had been eradicated. Of these patients, two in the azithromycin and one in the cefaclor group also relapsed clinically; the others remained asymptomatic. Patients tolerated both treatments well; treatment-related adverse events were recorded in 11% of the 267 azithromycin- and 10% of the 263 cefaclor-treated patients assessed for safety. One azithromycin patient and five cefaclor patients withdrew because of adverse events. The results of the study show that a 3-day regimen of azithromycin, given once daily, is as effective and well tolerated as a multiple-daily, 10-day cefaclor regimen for the treatment of upper respiratory tract infections in adults.