title: Central effects of H1 and H2 antihistamines.
abstract: H1-antihistamines are usually associated with impairment of central nervous functions, but unacceptable decrements in performance may not be an inevitable sequel of their use. Effects are dependent on the ability of a particular drug to cross the blood brain barrier, and so compounds which cross so slowly that tolerance of the central nervous system can develop gradually without any immediate changes in performance are of interest. However, sustained release formulations and compounds which have a selective affinity for the peripheral receptor may also have their part to play in the management of allergic states in those involved in skilled activity. As far as H2-antagonists are concerned, it is likely that as they are less liposoluble they would be free of central effects. Studies on the central effects of H1 and H2 antagonists are reviewed, and tentative recommendations are made in respect of these findings concerning the possible use of these drugs in aircrew.
authors.forename: A N
authors.initials: AN
authors.lastname: Nicholson
mesh_terms: D000337:Aerospace Medicine; D001559:Benzhydryl Compounds / Q000009:adverse effects; D002490:Central Nervous System / Q000187:drug effects*; D002744:Chlorpheniramine / Q000009:adverse effects; D002927:Cimetidine / Q000009:adverse effects; D002974:Clemastine / Q000009:adverse effects; D006634:Histamine H1 Antagonists / Q000009:adverse effects*; D006635:Histamine H2 Antagonists / Q000009:adverse effects*; D006801:Humans; D010640:Phenothiazines / Q000009:adverse effects; D011398:Promethazine / Q000009:adverse effects; D011597:Psychomotor Performance / Q000187:drug effects; D011899:Ranitidine / Q000009:adverse effects; D012894:Sleep Stages / Q000187:drug effects; D013329:Structure-Activity Relationship; D016593:Terfenadine; D014792:Visual Acuity / Q000187:drug effects; D014796:Visual Perception / Q000187:drug effects
chemical_list: D001559:Benzhydryl Compounds; D006634:Histamine H1 Antagonists; D006635:Histamine H2 Antagonists; D010640:Phenothiazines; D002744:Chlorpheniramine; D016593:Terfenadine; D002927:Cimetidine; D011899:Ranitidine; D002974:Clemastine; D011398:Promethazine; C006069:mequitazine