DIRITHROMYCIN IN THE TREATMENT OF STREPTOCOCCAL PHARYNGITIS

A double-blind, double-dummy, randomized, multicentre study compared the safety and the efficacy of dirithromycin (two 250 mg tablets, once daily) to erythromycin base (four 250 mg tablets, four times daily) for ten days in the treatment of proven group A 0-haemorytic (GABHs) streptococcal pharyngitis. Five-hundred and fifty-three patients (265 dirithromycin, 288 erythromycin) were enrolled in the trial and analysed for efficacy and safety. Clinical and bacteriological evaluations were performed pre-therapy, during therapy (days 3-5), post-therapy (three to five days after completion of treatment), and late post-therapy (three to five weeks after treatment). All patients qualified for safety analysis. A negative pre-therapy culture was the predominant reason a patient did not qualify for analysis of efficacy. At post-therapy, favourable clinical responses (cure or improvement) were reported for 94-1% (159/169) of dirithromycin and 94-6% (158/167) of erythromycin patients who qualified for efficacy analysis. Post-therapy throat cultures were negative for GABH streptococci in 79-3% (134/169) of dirithromycin patients and 86-2% (144/167) of patients treated with erythromycin (P = 0-314). At late post-therapy 87-6% (134/153) of dirithromycin and 88-7% (134/151) of erythromycin patients reported a favourable clinical response; pathogens were absent in 69-9% (107/153) of dirithromycin and 86-1% (130/151) of erythromycin patients (P = fr001). The adverse event profile of the two drugs was comparable although digestive and cutaneous adverse events were reported more frequently in the erythromycin treatment group. In this study, more dirithromycin patients had throat cultures positive for GABH streptococci at late post-therapy. The majority of patients with bacteriological relapse were symptomatically cured or improved and, thus, may represent chronic carrie rs of GABH streptococci. In addition, patients treated with an earlier tablet formulation of dirithromycin (Thomae) accounted for the majority of the unfavourable bacteriological outcomes. Overall, the efficacy and safety of dirithromycin and of erythromycin were comparable in the treatment of acute pharyngitis. © 1993 The British Society for Antimicrobial Chemotherapy.