Central effects of fexofenadine and cetirizine: Measurement of psychomotor performance, subjective sleepiness, and brain histamine H1-receptor occupancy using 11C-doxepin positron emission tomography

Manabu Tashiro, Yumiko Sakurada, Kentaro Iwabuchi, Hideki Mochizuki, Motohisa Kato, Mariko Aoki, Yoshihito Funaki, Masatoshi Itoh, Ren Iwata, Dean F. Wong, Kazuhiko Yanai

Research output: Contribution to journalArticlepeer-review

111 Scopus citations


Histamine H1-receptor (H1R) antagonists, or antihistamines, often induce sedative side effects when used for the treatment of allergic disorders. This study compared the sedative profiles of the second-generation antihistamines, fexofenadine and cetirizine, using 3 different criteria: subjective sleepiness evaluated by the Stanford Sleepiness Scale, objective psychomotor tests (simple and choice reaction time tests and visual discrimination tests at 4 different exposure durations), and measurement of histamine H1-receptor occupancy (H1RO) in the brain. Subjective sleepiness and psychomotor performance were measured in 20 healthy Japanese volunteers at baseline and 90 min after administration of fexofenadine 120 mg or cetirizine 20 mg in a double-blind, placebo-controlled crossover study. Hydroxyzine 30 mg was included as a positive control. H1RO was measured using positron emission tomography (PET) with 11C-doxepin in 12 of the 20 subjects, and a further 11 volunteers were recruited to act as controls. In psychomotor tests, fexofenadine was not significantly different from placebo and significantly less impairing than cetirizine on some tasks, as well as significantly less impairing than hydroxyzine on all tasks. For subjective sleepiness, fexofenadine was not significantly different from placebo, whereas cetirizine showed a trend toward increased sleepiness compared with fexofenadine and placebo. H1RO was negligible with fexofenadine (-0.1%) but moderately high with cetirizine (26.0%). In conclusion, fexofenadine 120 mg is distinguishable from cetirizine 20 mg, as assessed by H1RO and psychomotor testing.

Original languageEnglish (US)
Pages (from-to)890-900
Number of pages11
JournalJournal of Clinical Pharmacology
Issue number8
StatePublished - Aug 2004
Externally publishedYes


  • Cetirizine
  • Fexofenadine
  • H1-receptor occupancy (H1RO)
  • Histamine H1-receptor (H1R)
  • Positron emission tomography (PET)
  • Psychomotor performance
  • Second-generation antihistamine
  • Sleepiness

ASJC Scopus subject areas

  • Pharmacology
  • Pharmacology (medical)


Dive into the research topics of 'Central effects of fexofenadine and cetirizine: Measurement of psychomotor performance, subjective sleepiness, and brain histamine H<sub>1</sub>-receptor occupancy using <sup>11</sup>C-doxepin positron emission tomography'. Together they form a unique fingerprint.

Cite this