Clarithromycin versus penicillin in the treatment of streptococcal pharyngitis.

The safety and efficacy of oral clarithromycin 250 mg every 12 h treatment and of oral penicillin VK (the potassium salt of phenoxymethylpenicillin) 250 mg every 6 h were compared in the treatment of streptococcal pharyngitis caused by Streptococcus pyogenes in an eight centre in-vivo study. A total of 243 patients were enrolled in the study and 125 patients were evaluated for efficacy; evaluable patients included 67 patients in the clarithromycin treatment group and 58 patients in the penicillin VK group. Both antibiotic regimens were effective in the treatment of streptococcal pharyngitis. The clinical cure rate during the initial post-treatment period (between two and ten days post-treatment) for the penicillin VK treated group was 98% (57/58) and for the clarithromycin treated group was 96% (64/67). The bacteriological cure rate during the initial post-treatment period for the penicillin VK treated group was 97% (56/58) and for the clarithromycin treated group was 100% (67/67). A total of 17 patients reported adverse events; seven patients were in the clarithromycin treatment group and ten patients in the penicillin VK treatment group. One patient in the penicillin VK group was withdrawn because of the severity of the adverse advent (balanitis). No clinically significant differences were reported between the two treatment groups for haematology, blood chemistry, or urinalysis evaluations. Oral clarithromycin 250 mg 12-hourly treatment was as safe and effective as penicillin VK 250 mg 6-hourly in the treatment of streptococcal pharyngitis.