title: Oral absorption of clarithromycin in acute illness and during convalescence in patients with community-acquired pneumonia.
abstract: OBJECTIVE
  To compare the extent of oral clarithromycin absorption in patients during an illness and in health.
  
  
  METHODS
  Sequential two-phase prospective study including an acutely ill pneumonia phase (PP) and a subsequent convalescent phase (CP).
  
  
  METHODS
  Patients >/= 18 years old with radiographically confirmed community-acquired pneumonia (CAP) who were admitted to the hospital.
  
  
  METHODS
  During both study phases, patients received one single 500-mg dose of oral clarithromycin. Serial blood samples were drawn over a 24-h period in order to characterize the plasma concentration-time curves. Area under the curve from zero to 24 h (AUC(0-24)), maximum plasma concentration (Cmax), and time to maximum concentration (Tmax) were determined for both clarithromycin and its metabolite, 14-hydroxyclarithromycin, and compared between the two phases.
  
  
  RESULTS
  Twelve patients completed both phases of the study. For clarithromycin, there was a significant increase AUC(0-24) (47.37 +/- 8.51 microg/h/mL vs 36.22 +/- 6.09 microg/h/mL) in favor of the PP. There were no significant differences detected with respect to Cmax (4.32 +/- 0.63 microg/mL vs 3.57 +/- 0.46 microg/mL), or Tmax (3.50 +/- 0.50 h vs 2.83 +/- 0.59 h) between PP and CP. For 14-hydroxyclarithromycin, the AUC(0-24) and Cmax were significantly higher (5.84 +/- 1.08 microg/h/mL vs 8.84 +/- 1.92 microg/h/mL; 0.42 +/- 0.08 microg/mL vs 0.76 +/- 0.23 microg/mL) in the CP as compared to the PP. Tmax remained unchanged.
  
  
  CONCLUSIONS
  The extent of absorption of oral clarithromycin was not diminished during an acute illness with CAP.
authors.affiliation: London Health Sciences Centre, London, Ontario, Canada.
authors.forename: E
authors.initials: E
authors.lastname: Offman
authors.forename: F
authors.initials: F
authors.lastname: Varin
authors.forename: T
authors.initials: T
authors.lastname: Nolan
authors.forename: C D
authors.initials: CD
authors.lastname: Bayliff
authors.forename: A M
authors.initials: AM
authors.lastname: Bombassaro
authors.forename: D G
authors.initials: DG
authors.lastname: McCormack
mesh_terms: D000042:Absorption; D000208:Acute Disease; D000284:Administration, Oral; D000368:Aged; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000493:pharmacokinetics*; D017291:Clarithromycin / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000097:blood / Q000493:pharmacokinetics*; D017714:Community-Acquired Infections / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000378:metabolism; D003289:Convalescence; D005260:Female; D006801:Humans; D008297:Male; D009061:Mouth Mucosa / Q000378:metabolism*; D018410:Pneumonia, Bacterial / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000378:metabolism*; D011379:Prognosis; D011446:Prospective Studies; D011859:Radiography; D012720:Severity of Illness Index
chemical_list: D000900:Anti-Bacterial Agents; C056228:14-hydroxyclarithromycin; D017291:Clarithromycin