Double-blind,double-dummy comparison of azithromycin and cephalexin in the treatment of skin and skin structure infections

In this double-blind, randomised trial conducted in 22 centres in the USA, azithromycin given over five days, as a once-a-day regimen, (500 mg on day 1, 250 mg on days 2–5) was compared with cephalexin (500 mg b.i.d.) given for ten days in the treatment of patients with skin and skin structure infections. A total of 366 patients entered the study and 179 of these were eligible for the efficacy analysis. The overall clinical response to azithromycin was 94.0 %, compared with 95.8 % for cephalexin. The clinical cure rates were 53.0 % for azithromycin and 59.4 % for cephalexin; the respective improvement rates were 41.0 % and 36.5 %. Distribution of response (cured, improved, failed) was similar in each group (p=0.37). The bacteriological eradication rate for azithromycin-treated patients was 94.2 % and for cephalexin-treated patients was 90.3 % (p=0.34). Clinical and bacteriological response was similar in each group for all primary diagnoses. The two antibiotics were well tolerated, the overall incidence of side effects being 13.7 % with approximately 60 % due to gastrointestinal disturbances. In all but one case (cephalexin) the severity of the reported side effects was mild or moderate. Six patients withdrew from the study due to treatment-related events; five had been treated with azithromycin and one with cephalexin. In summary, a five-day, once-daily regimen of azithromycin was as effective as a ten-day, twice-daily regimen of cephalexin in the treatment of patients with skin and skin structure infections.