[Treatment of streptococcal tonsillitis with once-a-day amoxicillin: a meta-analysis]

The objective of this systematic review is to determine if the treatment of streptococcal pharyngitis with a daily dose of amoxicillin is similar in effectiveness to other dosing schedules (every 6, 8 or 12 hours) of the same antibiotic or penicillin V.

Randomised clinical trials (RCT) comparing amoxicillin (one dose per day) compared to other dosages of amoxicillin (every 8-12 hours) or penicillin V (every 6, 8 or 12 hours). Search databases consulted: Medline, Central, EMBASE and Google Scholar. The results were combined using the risk difference (RD). We measured the effectiveness of each treatment with a negative throat culture on the 14-21th day, being previously positive to group A Streptococcus (under a non-inferiority hypothesis, where the upper limit of the 95% confidence interval [95% CI] of the DR does not exceed 10%) and clinical failure on days 10-21. The results were combined according to a fixed effects model or random depending on whether or not there was heterogeneity.

Four RCT met the selection criteria with 1,314 participants (657 received amoxicillin once per day, and 657 received other antibiotics or dosages): a) any positive culture for Streptococcus (14-21st day, 4 RCTs): DR: -0.5% (95% CI: -5.1% to 4.2%; b) persistence of the same serotype (14-21st day, 3 RCT): DR: 0.32% (95% CI: -3.1% to 3.7%; c) clinical failure (2 RCT): DR: 1.7% (95% CI: -1.9% to 5.4%; d) adverse effects (4 RCT): DR: -0.39% (95% CI: -1.5% to 6.8%). There were no statistically significant differences in any comparisons.

Amoxicillin, administered once daily is not inferior to other dosages of the same antibiotic or penicillin V. These results are important because they may facilitate compliance.