title: Factors associated with loss of penicillin G concentrations in serum after intramuscular benzathine penicillin G injection: a meta-analysis.
abstract: BACKGROUND
  An interval of 3-4 weeks between intramuscular injections of 1.2 million units of benzathine penicillin G as prophylaxis against group A streptococcal infection is recommended by health organizations for patients with pediatric rheumatic fever and heart disease.
  
  
  METHODS
  We reviewed the literature for evidence of the persistence of serum penicillin G during the first 4 weeks after the recommended dose of benzathine penicillin G.
  
  
  RESULTS
  The weighted-mean concentration was <0.02 µg/mL by 3 weeks after the initial dose. Weighted means were lower in studies done after 1990 than before (P<0.01), in studies dealing with secondary versus primary prophylaxis (P<0.01) and in studies in children versus those in adults (P<0.02).
  
  
  CONCLUSIONS
  Recommendations for benzathine penicillin G prophylaxis may need reevaluation.
authors.affiliation: Henry M. Jackson Foundation at The Operational Infectious Diseases Department, Naval Health Research Center, San Diego, CA 92106, USA. michael.broderick@med.navy.mil
authors.forename: Michael P
authors.initials: MP
authors.lastname: Broderick
authors.forename: Christian J
authors.initials: CJ
authors.lastname: Hansen
authors.forename: Dennis J
authors.initials: DJ
authors.lastname: Faix
mesh_terms: D000328:Adult; D000900:Anti-Bacterial Agents / Q000008:administration & dosage* / Q000097:blood / Q000493:pharmacokinetics*; D019072:Antibiotic Prophylaxis / Q000379:methods*; D002648:Child; D002675:Child, Preschool; D006801:Humans; D007273:Injections, Intramuscular; D010401:Penicillin G Benzathine / Q000008:administration & dosage* / Q000097:blood / Q000493:pharmacokinetics*; D044967:Serum / Q000737:chemistry; D013290:Streptococcal Infections / Q000517:prevention & control
chemical_list: D000900:Anti-Bacterial Agents; D010401:Penicillin G Benzathine