University of Michigan
Department of Pediatrics
Evidence-Based Pediatrics Web Site

Question

• How effective is BID dosing penicillin in treating streptococcal pharyngitis compared to TID dosing of penicillin?

Clinical Bottom Lines

1. BID penicillin is just as effective as TID/QID dosing of penicillin in treating streptococcal pharyngitis.
   
2. QD penicillin was found to have a lower cure rate, compared to more frequent dosing.
3. There is no data to show that this regimen prevents rheumatic fever.

Summary of Key Evidence

1. A meta-analysis compared 6 studies that looked at the dosing interval of penicillin for streptococcal pharyngitis, specifically QD/BID vs TID/QID.¹
2. Each study was assigned a quality score based on 3 categories: 1) diagnostic accuracy (if the study was done Dec-May, excluded anyone less than 3 years, and if diagnosis was made by symptoms of streptococcal pharyngitis, not viral pharyngitis); 2) distinguish re-infection after cure from persistent infection (follow-up cultures within 14 days of completing treatment; comparing pre-treatment and post-treatment GABHS serotypes); 3) general elements of study design (investigators blind to treatment, compliance of treatment assessed, subject withdrawals and reasons for withdrawal discussed, assessed adequacy of randomization by demographic variables).
3. The meta-analysis measured the difference in the proportion of each treament group cured, with a 95% confidence interval.
4. There was no difference in the cure rate between BID and TID/QID dosing of penicillin.
5. QD dosing of penicillin had a decreased efficacy in treating streptococcal pharyngitis.
6. The study also analyzed a few subgroups: no difference in cure rate was found within the pediatric population; no difference was found based on the total daily dose of penicillin.
7. Of the 6 studies analyzed, only one study had a treatment arm for amoxicillin.

Additional Comments

• The meta-analysis was valid: the studies included were all randomized controlled trials, the results were consistent from study to study.
• The difference between study designs made the analysis more difficult.
• The analysis did not assess the power of the study.
• More studies need to be done to assess dosing frequency of amoxicillin against streptococcal pharyngitis.
  

Citation

1. Lan AJ, Colford JM. The impact of dosing frequency on the efficacy of 10-day penicillin or amoxicillin therapy for streptococcal tonsillopharyngitis: a meta-analysis. Pediatrics 2000; 105: e19.
   

CAT Author: Lynn Johnson, MD

CAT Appraisers: Alex Kemper, MD

Date appraised: July 30, 2001