title: Differential cognitive effects of terfenadine and chlorpheniramine.
abstract: The H1-histamine antagonist, terfenadine, has been proposed to have reduced cognitive side effects. In the present study, the relative cognitive effects of terfenadine, 60 mg, chlorpheniramine maleate, 8 mg, and placebo were tested with a double-blind, randomized, three-period crossover design in 24 healthy adult subjects. The dependent variable was latency of the P3-evoked potential. The P3 is a cognitively evoked electroencephalographic response that is an objective and sensitive measure of sustained attention and cerebral processing speed. Disease and drug states that adversely affect the central nervous system can slow P3 latency. For example, the centrally active anticholinergic scopolamine slows cognitive processing speed and prolongs P3 latency. P3 latency (millisecond) means (+/- mean standard error) were pretreatment, 310 (+/- 1.7; placebo, 313 (+/- 3); terfenadine, 320 (+/- 3); and chlorpheniramine, 333 (+/- 3). The findings suggest that terfenadine may be particularly advantageous in patients who require alertness and intact cognitive abilities.
authors.affiliation: Department of Neurology, Medical College of Georgia, Augusta 30912.
authors.forename: K J
authors.initials: KJ
authors.lastname: Meador
authors.forename: D W
authors.initials: DW
authors.lastname: Loring
authors.forename: E E
authors.initials: EE
authors.lastname: Thompson
authors.forename: W O
authors.initials: WO
authors.lastname: Thompson
mesh_terms: D000328:Adult; D001559:Benzhydryl Compounds / Q000494:pharmacology*; D002744:Chlorpheniramine / Q000494:pharmacology*; D003071:Cognition / Q000187:drug effects*; D004311:Double-Blind Method; D005073:Evoked Potentials, Somatosensory / Q000187:drug effects; D005260:Female; D006634:Histamine H1 Antagonists / Q000494:pharmacology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011897:Random Allocation; D011930:Reaction Time / Q000187:drug effects; D016593:Terfenadine
chemical_list: D001559:Benzhydryl Compounds; D006634:Histamine H1 Antagonists; D002744:Chlorpheniramine; D016593:Terfenadine