title: Facial thermography is a sensitive tool to determine antihistaminic activity: comparison of levocetirizine and fexofenadine.
abstract: OBJECTIVE
  To assess the antihistaminic activity of levocetirizine and fexofenadine 2 h and 24 h after drug administration using facial thermography and to compare the results with those using well-established parameters of antihistaminic activity in the nose and skin.
  
  
  METHODS
  This was a randomized, double-blind, three-treatment, three-period, single-dose, cross-over study in healthy males taking levocetirizine 5 mg, fexofenadine 120 mg or placebo. The primary endpoint was nasal skin temperature after nasal histamine challenge recorded for 20 min at 2 and 24 h after drug intake. The secondary endpoints were nasal symptoms and a histamine skin prick test.
  
  
  RESULTS
  Thirty subjects were randomized. At 2 h after drug intake the inhibition of the nasal temperature increase from baseline was not significantly different between levocetirizine and fexofenadine. At 24 h it was significantly more pronounced after levocetirizine than fexofenadine (difference: least-squares mean: -0.13 degrees C; P < or = 0.024, 95% CI -0.24, -0.02). Both drugs significantly reduced (P < or = 0.001) the mean temperature increase from baseline compared with placebo at 2 and 24 h (least-squares mean increase and (95% CI): levocetirizine, -0.28 degrees C (-0.42, -0.14) and -0.32 degrees C (-0.43, -0.21); fexofenadine -0.35 degrees C (-0.49, -0.21) and -0.19 degrees C (-0.30, -0.08), respectively). Results of nasal symptom score and wheal and flare were consistent with the thermography results.
  
  
  CONCLUSIONS
  Facial thermography is an objective, non-invasive and sensitive method to study antihistaminic activity at the nose level. Levocetirizine and fexofenadine demonstrate the same activity at 2 h after drug intake, but levocetirizine has a more sustained activity at 24 h.
authors.affiliation: Fraunhofer Institute for Toxicology and Experimental Medicine, Hanover, Germany. larbig@item.fraunhofer.de
authors.forename: Michael
authors.initials: M
authors.lastname: Larbig
authors.forename: Bernard
authors.initials: B
authors.lastname: Burtin
authors.forename: Laurent
authors.initials: L
authors.lastname: Martin
authors.forename: Holger
authors.initials: H
authors.lastname: Stamm
authors.forename: Birgit
authors.initials: B
authors.lastname: Luettig
authors.forename: Jens M
authors.initials: JM
authors.lastname: Hohlfeld
authors.forename: Norbert
authors.initials: N
authors.lastname: Krug
mesh_terms: D000293:Adolescent; D000328:Adult; D017332:Cetirizine / Q000494:pharmacology*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005145:Face / Q000502:physiology*; D006632:Histamine / Q000276:immunology; D039563:Histamine H1 Antagonists, Non-Sedating / Q000494:pharmacology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009299:Nasal Provocation Tests / Q000379:methods; D009666:Nose / Q000473:pathology / Q000503:physiopathology; D010879:Piperazines / Q000494:pharmacology*; D012881:Skin Temperature / Q000187:drug effects; D016593:Terfenadine / Q000031:analogs & derivatives* / Q000494:pharmacology; D013817:Thermography / Q000379:methods*
chemical_list: D039563:Histamine H1 Antagonists, Non-Sedating; D010879:Piperazines; C472067:levocetirizine; D016593:Terfenadine; D006632:Histamine; C093230:fexofenadine; D017332:Cetirizine