title: Placental passage of clarithromycin surpasses other macrolide antibiotics.
abstract: OBJECTIVE
  Infection of the amnion cavity with Ureaplasma urealyticum continues to be a therapeutic challenge. The transplacental transfer rates of macrolide antibiotics are low, and tetracyclines and quinolones are contraindicated in pregnancy. The aim of this study was to investigate placental transfer of clarithromycin in a well-studied placental perfusion model to determine whether clarithromycin surpasses the transfer rate of other macrolide antibiotics in similar models.
  
  
  METHODS
  Ten placentas that were obtained immediately after delivery were perfused with clarithromycin (3 microg/mL) plus a reference substance (antipyrine). Open circulation placental preparations were used to evaluate steady-state pharmacodynamics and transplacental gradient formation. Drug concentrations were measured by high-performance liquid chromatography.
  
  
  RESULTS
  The mean transplacental transfer of clarithromycin was 6.1% (95% CI, 1.8%).
  
  
  CONCLUSIONS
  Because of its enhanced placental passage compared with other macrolide antibiotics, clarithromycin that is given after the first trimester (after embryogenesis) may be an appropriate candidate in treatment trials of genital mycoplasma and ureaplasma infections during pregnancy.
authors.affiliation: Department of Obstetrics and Fetomaternal Medicine, University of Vienna Medical School, Austria. armin.witt@akh-wien.ac.at
authors.forename: Armin
authors.initials: A
authors.lastname: Witt
authors.forename: Eva Maria
authors.initials: EM
authors.lastname: Sommer
authors.forename: Margit
authors.initials: M
authors.lastname: Cichna
authors.forename: Karl
authors.initials: K
authors.lastname: Postlbauer
authors.forename: Alexander
authors.initials: A
authors.lastname: Widhalm
authors.forename: Hubertus
authors.initials: H
authors.lastname: Gregor
authors.forename: Klaus
authors.initials: K
authors.lastname: Reisenberger
mesh_terms: D000900:Anti-Bacterial Agents / Q000493:pharmacokinetics*; D002851:Chromatography, High Pressure Liquid; D017291:Clarithromycin / Q000493:pharmacokinetics*; D005260:Female; D006706:Homeostasis; D006801:Humans; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy
chemical_list: D000900:Anti-Bacterial Agents; D017291:Clarithromycin