Treatment of streptococcal pharyngitis with amoxycillin once a day.

OBJECTIVE: To evaluate treatment of group A beta haemolytic streptococcal pharyngitis with amoxycillin once daily compared with phenoxymethylpenicillin three or four times a day.

DESIGN: Randomised controlled study of consecutive patients presenting with symptoms suggestive of group A beta haemolytic streptococcal pharyngitis in whom culture of a throat swab yielded positive results.

SETTING: Five family medicine practices.

SUBJECTS: 157 patients aged over 3 years who required treatment with antibiotics.

MAIN OUTCOME MEASURES: Clinical response, bacteriological response, days at work and school lost, and compliance.

RESULTS: During the period of the study 393 patients presented with symptoms suggesting streptococcal pharyngitis; 157 of them had throat swabs that yielded positive results on culture. Eighty two were treated with phenoxymethylpenicillin and 75 with amoxycillin. No difference was observed in the clinical response, days at work and school lost (139 days for 64 patients taking phenoxymethylpenicillin v 100 days for 57 patients taking amoxycillin; p > 0.2), or residual positive cultures after two days (6 (7.3%) v 3 (4%); p > 0.5). A significant difference in the bacteriological response was found after 14 days (5 (6.1%) v 0; p < 0.04) with no positive cultures observed in the amoxycillin group.

CONCLUSIONS: These findings support the hypothesis that amoxycillin once daily is as effective as phenoxymethylpenicillin in the treatment of group A beta haemolytic streptococcal pharyngitis.