title: Passive absorption of fentanyl from the fentanyl HCl iontophoretic transdermal system.
abstract: BACKGROUND
  The fentanyl HCl iontophoretic transdermal system (ITS) is a patient-controlled analgesic delivery system that actively administers bolus doses of fentanyl transdermally upon patient activation.
  
  
  OBJECTIVE
  To determine the amount of fentanyl absorbed from fentanyl ITS via passive absorption over a 24.5-h period.
  
  
  METHODS
  Serial blood samples for pharmacokinetic analyses were obtained from healthy adults who received fentanyl ITS for 24 h.
  
  
  RESULTS
  The average absorption rate was 2.3 microg/h. An average total of 57.4 microg fentanyl was absorbed during the study. The mean maximum observed serum fentanyl concentration was 0.06 ng/mL.
  
  
  CONCLUSIONS
  Results indicate that the average amount of fentanyl absorbed passively or via passive delivery from fentanyl ITS is minimal. Maximum serum fentanyl concentrations fell below the range associated with analgesia and respiratory depression. The variability in fentanyl exposure was likely exaggerated by the low amounts of drug absorption resulting in overall fairly low fentanyl concentrations.
authors.affiliation: ALZA Corporation, Mountain View, CA, USA.
authors.forename: Gayatri
authors.initials: G
authors.lastname: Sathyan
authors.forename: Brad
authors.initials: B
authors.lastname: Phipps
authors.forename: Suneel K
authors.initials: SK
authors.lastname: Gupta
mesh_terms: D000279:Administration, Cutaneous; D000328:Adult; D000701:Analgesics, Opioid / Q000097:blood / Q000493:pharmacokinetics*; D019540:Area Under Curve; D002853:Chromatography, Liquid; D005283:Fentanyl / Q000097:blood / Q000493:pharmacokinetics*; D006801:Humans; D007478:Iontophoresis; D008875:Middle Aged; D053719:Tandem Mass Spectrometry
chemical_list: D000701:Analgesics, Opioid; D005283:Fentanyl