A comparison of azithromycin and penicillin V for the treatment of streptococcal pharyngitis.

The safety and efficacy of azithromycin was compared with that of penicillin V in a multicenter study of the treatment of streptococcal pharyngitis in outpatients. Patients were randomized in a 2:1 ratio to either azithromycin 500 mg once on day 1 followed by 250 mg once daily for 4 days, or penicillin V (V-Cillin K) 250 mg every 6 hours for 10 days. Two hundred and forty-two patients from 29 centers were evaluable at the 11th day after enrollment. Five of 229 (2.2%) azithromycin-treated patients were not evaluable because their enrollment isolates of group A beta-hemolytic streptococci (GABHS) were resistant to the drug. In both treatment groups, 99% of patients were clinically cured or improved. Eradication of GABHS occurred in 91% of azithromycin-treated patients compared with 96% of penicillin-treated patients (p = 0.21). Of the patients who had a recurrence of GABHS, clinical evidence of infection occurred in 3 of 13 (23%) patients who had been treated with azithromycin and in 7 of 10 (70%) patients treated with penicillin. Adverse events, generally mild to moderate gastrointestinal complaints, were significantly more common in the azithromycin-treated patients (16.6%) than in penicillin-treated patients (1.7%) (p less than 0.001). Discontinuation because of side effects occurred with similar frequency in both groups. Azithromycin appears to be a safe and effective alternative treatment for streptococcal pharyngitis in adult outpatients.