title: An investigation into the effects of cetirizine on cognitive function and psychomotor performance in healthy volunteers.
abstract: OBJECTIVE
  The cognitive and psychomotor effects of 2.5, 5 and 10 mg cetirizine, a second-generation H1 receptor antagonist, were compared with loratadine 10, 20 and 40 mg, promethazine 25 mg and placebo in 24 healthy volunteers in a double-blind, randomised cross-over study.
  
  
  METHODS
  Following each dose, subjects were required to perform a series of tests of cognitive function and psychomotor performance at 1.5, 3 and 6 h post-dose. The test battery consisted of critical flicker fusion (CFF), choice reaction time (CRT), compensatory tracking task (CTT) and assessment of subjective sedation (LARS).
  
  
  RESULTS
  Cetirizine and loratadine at all doses tested were not significantly different from placebo in any of the tests used. However, as expected for a verum, all measures with the exception of CTT were significantly disrupted by promethazine (P < 0.05). Promethazine caused a reduction in CFF threshold at all test points; these differences were significant at 3 h and 6 h post-dose (P < 0.05). There was also a significant increase in total reaction time at 3 h post-promethazine administration. Subjective reports of sedation were significantly greater following the administration of promethazine at all time points (P < 0.05).
  
  
  CONCLUSIONS
  These results allow the conclusion that cetirizine at its recommended therapeutic dose of 10 mg is demonstrably free from disruptive effects on aspects of psychomotor and cognitive function in a study where the psychometric assessments have been shown to be sensitive to impairment, as evidenced by the effects of the positive control, promethazine 25 mg.
authors.affiliation: HPRU Medical Research Centre, University of Surrey, Egerton Road, Guildford, GU2 5XP, United Kingdom. z.shamsi@surrey.ac.uk
authors.forename: Z
authors.initials: Z
authors.lastname: Shamsi
authors.forename: S
authors.initials: S
authors.lastname: Kimber
authors.forename: I
authors.initials: I
authors.lastname: Hindmarch
mesh_terms: D000328:Adult; D017332:Cetirizine / Q000494:pharmacology*; D003071:Cognition / Q000187:drug effects*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D005425:Flicker Fusion / Q000187:drug effects; D006634:Histamine H1 Antagonists / Q000494:pharmacology*; D006801:Humans; D017336:Loratadine / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D011398:Promethazine / Q000494:pharmacology; D011597:Psychomotor Performance / Q000187:drug effects*; D011930:Reaction Time
chemical_list: D006634:Histamine H1 Antagonists; D017336:Loratadine; D011398:Promethazine; D017332:Cetirizine