title: Antihistamines and aircrew: usefulness of fexofenadine.
abstract: BACKGROUND
  The aim of this study was to establish whether fexofenadine hydrochloride, an antihistamine, modulates daytime sleepiness or performance.
  
  
  METHODS
  The effects of fexofenadine (120, 180, and 240 mg) on digit symbol substitution, tracking, and vigilance tasks, and on objective (multiple sleep latency test) and subjective sleepiness, were studied in six healthy volunteers (two males, four females, aged 20-34 [mean 26.5] yr) from 1 h pre-ingestion to 8 h post-ingestion. The study was placebo-controlled and double-blind with a six-way cross-over design. The centrally acting antihistamine, promethazine (10 mg), was used as an active control to confirm the sensitivity of the experimental procedures.
  
  
  RESULTS
  There were no changes in performance or sleepiness with any dose of fexofenadine at any time, compared with placebo. Promethazine, compared with both placebo and fexofenadine, impaired performance on the digit symbol substitution task (2.5 h post-ingestion), vigilance task (2.5-5h post-ingestion) and tracking task (2.5-3.5 h post-ingestion), increased objective sleepiness (1.5-2.5 h post-ingestion) and subjective sleepiness (1.5-8h post-ingestion).
  
  
  CONCLUSIONS
  Consideration may be given to the clinical use of currently licensed doses of fexofenadine (120-180 mg) by individuals involved in skilled activity. Fexofenadine may be potentially useful for aircrew.
authors.affiliation: Defence Evaluation and Research Agency, Centre for Human Sciences, Farnborough, Hampshire, UK.
authors.forename: A N
authors.initials: AN
authors.lastname: Nicholson
authors.forename: B M
authors.initials: BM
authors.lastname: Stone
authors.forename: C
authors.initials: C
authors.lastname: Turner
authors.forename: S L
authors.initials: SL
authors.lastname: Mills
mesh_terms: D000328:Adult; D000337:Aerospace Medicine; D001288:Attention / Q000187:drug effects; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D006634:Histamine H1 Antagonists / Q000008:administration & dosage / Q000494:pharmacology*; D006801:Humans; D008297:Male; D011398:Promethazine / Q000494:pharmacology; D012894:Sleep Stages / Q000187:drug effects*; D016593:Terfenadine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: D006634:Histamine H1 Antagonists; D016593:Terfenadine; C093230:fexofenadine; D011398:Promethazine