title: Cognitive effects of intramuscular ketamine and oral triazolam in healthy volunteers.
abstract: BACKGROUND
  Several studies have documented impairments in memory processes as a result of ketamine administration; however, few studies have compared the profile of cognitive effects of ketamine to other drugs.
  
  
  OBJECTIVE
  The aim of this study was to compare the cognitive effects of ketamine with those of triazolam in healthy volunteers.
  
  
  METHODS
  Doses of ketamine (0.2, 0.4 mg/kg intramuscular (i.m.)), triazolam (0.2, 0.4 mg/70 kg p.o.), and double-dummy placebos were administered to 20 volunteers under repeated measures, counterbalanced, double-blind conditions. Peak physiological, psychomotor, subjective, and cognitive effects were examined.
  
  
  RESULTS
  Ketamine impaired balance when balance was assessed early in the task order, whereas triazolam impaired psychomotor coordination and divided attention irrespective of task order. Triazolam also tended to produce greater effects on working memory and episodic memory tasks than ketamine at doses that produced lower subjective effects and higher estimates of performance.
  
  
  CONCLUSIONS
  Ketamine produces less cognitive impairment than triazolam at doses that produced greater subjective effects. Thus ketamine does not produce the underestimation of cognitive impairment typically seen with triazolam.
authors.affiliation: Department of Pharmacology and Toxicology, University of Arkansas for Medical Sciences, 4301 W. Markham Street, Little Rock, AR 72205, USA.
authors.forename: Lawrence P
authors.initials: LP
authors.lastname: Carter
authors.forename: Bethea A
authors.initials: BA
authors.lastname: Kleykamp
authors.forename: Roland R
authors.initials: RR
authors.lastname: Griffiths
authors.forename: Miriam Z
authors.initials: MZ
authors.lastname: Mintzer
mesh_terms: D000759:Adjuvants, Anesthesia / Q000008:administration & dosage / Q000009:adverse effects*; D000284:Administration, Oral; D000328:Adult; D000778:Anesthetics, Dissociative / Q000008:administration & dosage / Q000009:adverse effects*; D003071:Cognition / Q000187:drug effects*; D003072:Cognition Disorders / Q000139:chemically induced; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007273:Injections, Intramuscular; D007649:Ketamine / Q000008:administration & dosage / Q000009:adverse effects*; D008297:Male; D008570:Memory, Short-Term / Q000187:drug effects; D011597:Psychomotor Performance / Q000187:drug effects; D014229:Triazolam / Q000008:administration & dosage / Q000009:adverse effects*; D055815:Young Adult
chemical_list: D000759:Adjuvants, Anesthesia; D000778:Anesthetics, Dissociative; D014229:Triazolam; D007649:Ketamine