Background: Acute pharyngotonsillitis (APT) is one of the most common inflammatory processes of adults and children in an outpatient setting. Increasing failure rates, hypersensitivity to penicillin, the required multiple daily doses and common side effects lead to poor patients compliance and thus inadequate treatment duration, providing therefore ground for considering alternative antimicrobial agents.
Material/Methods: This multicenter, randomized, single blind study was undertaken in order to compare efficacy and safety of cefaclor (375 mg BID) and amoxicillin/clavulanate (625 mg BID) in 10 days treatment regiment of ambulatory patients with APT. A total of 200 patients (age range between 12-65 years) with symptoms of APT and positive antigen strep test were enrolled into the study. Clinical and bacteriological responses were assessed after the end of treatment (14th-18th day) and at the follow-up visit (38th-45th day). All GABHS strains, isolated from throat cultures, were tested for in vitro sensitivity to the antibiotics used in the study and no strain was found resistant to both antibiotics.
Results: The results indicated that both antibiotics had high - almost 99&percnt; effectiveness at the post therapy visit. On the follow up visit an increased tendency of relapses was observed in the amoxicillin/clavulanate treated group, compared to cefaclor treated group (8.33&percnt; vs 3.29&percnt;). Relative risk of relapse in patients treated with amoxicillin/clavulanate was 2.6 greater compared to cefaclor. There were significantly higher rates of gastrointestinal adverse events in group treated with amoxicillin/clavulanate (29/97 patients; 29.89&percnt;) compared to cefaclor (16/95 patients; 16.84&percnt;) - p< 0.03. Frequency of other adverse events did not differ significantly between the groups.
Conclusions: Cefaclor and amoxicillin/clavulonate provide a clinically and bacteriologically effective treatment for patients with pharyngotonsillitis caused by GABHS, but cefaclor treatment is significantly safer in regard to gastrointestinal side effects.

Keywords: Cefaclor, amoxicillin/clavulanate acid, tonsillopharyngitis, adults, Safety, efficacy, Streptococcus pyogenes, GABHS