ABSTRACT
Objective: To compare clinical and bacteriologic responses to intramuscular benzathine penicillin G (BPG) and single dose of amoxicillin in Group A streptococcal (GAS) pharyngitis. Design: This study included 571 children from 6 to 15 years old age; with pharyngitis; who were admitted to 45 elementary and guidance schools from 7 regions of Education Organization in North-East of Iran; Mashhad. They were screened for enrollment and if he/she presented pharyngitis with clinical criteria of sore throat; erythema; exudate and tender or enlarged anterior cervical lymph nodes. Exclusion criteria included reports of antibiotic use; negative throat culture for GAS and history of allergy to the drugs. Clinical and bacteriologic responses to BPG and once daily orally amoxicillin were considered and compared. Results: In the amoxicillin group; treatment failure was more than the penicillin group (18.9 vs. 6.4; respectively) but the difference was not statistically significant (p 0.05). Both drugs were significantly effective in reducing pharyngitis manifestations but penicillin was significantly more effective in reducing exudate than amoxicillin. Conclusion: Our study was in line with studies comparing the two drugs. The results show that once-daily therapy with amoxicillin is as effective as intramuscular benzathine penicillin G for the treatment of GAS pharyngitis; but penicillin was significantly more effective in reducing exudate and concurrent signs vs. amoxicillin