Facial thermography is a sensitive tool to determine antihistaminic activity: comparison of levocetirizine and fexofenadine.
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.
Larbig
Michael
M
Fraunhofer Institute for Toxicology and Experimental Medicine, Hanover, Germany. larbig@item.fraunhofer.de
Burtin
Bernard
B
Martin
Laurent
L
Stamm
Holger
H
Luettig
Birgit
B
Hohlfeld
Jens M
JM
Krug
Norbert
N
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*
D039563:Histamine H1 Antagonists, Non-Sedating; D010879:Piperazines; C472067:levocetirizine; D016593:Terfenadine; D006632:Histamine; C093230:fexofenadine; D017332:Cetirizine