title: A randomized, placebo-controlled laboratory study of the effects of D-cycloserine on craving in cocaine-dependent individuals.
abstract: BACKGROUND
  D-Cycloserine (DCS), a partial glutamate N-methyl-D-aspartate (NMDA) receptor agonist, enhances extinction of conditioned fear responding; preliminary data suggest that it may facilitate extinction of drug cue reactivity.
  
  
  OBJECTIVE
  This study investigates DCS effects on cocaine cue craving and drug use in cocaine-dependent subjects.
  
  
  METHODS
  Thirty-two subjects were randomly assigned to receive (1) DCS only, (2) DCS before sessions 1 and 3, placebo (PBO) before session 2, or (3) PBO only 15-min before each of 3 1-h cocaine cue exposure sessions conducted 1 day apart. Craving ratings were obtained before, during, and after sessions. Drug use and cue-induced craving were assessed 1 week after the last cue session.
  
  
  RESULTS
  Repeated presentation of cocaine cues resulted in decreased craving both within and between sessions. DCS did not facilitate extinction learning and may have enhanced craving. The group that received three doses of DCS had significantly higher craving than the PBO group at the baseline ratings taken before sessions 2 and 3, as well as significantly higher cue-induced craving at follow-up. The group that received two doses of DCS did not differ from the PBO group. There were no group differences in postextinction cocaine use.
  
  
  CONCLUSIONS
  The reduction of cocaine cue reactivity in the PBO group suggests that the study procedures were sufficient to produce extinction. Under these conditions, DCS did not facilitate extinction and may have enhanced craving. Further studies of glutamatergic agents and extinction in cocaine dependence should include consideration of procedural variables that could have a major impact on study outcomes.
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Division of Clinical Neuroscience, Medical University of South Carolina, 67 President Street MSC 861, Charleston, SC 29425, USA. kimber.l.price@gmail.com
authors.forename: Kimber L
authors.initials: KL
authors.lastname: Price
authors.forename: Nathaniel L
authors.initials: NL
authors.lastname: Baker
authors.forename: Aimee L
authors.initials: AL
authors.lastname: McRae-Clark
authors.forename: Michael E
authors.initials: ME
authors.lastname: Saladin
authors.forename: Stacia M
authors.initials: SM
authors.lastname: Desantis
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Santa Ana
authors.forename: Kathleen T
authors.initials: KT
authors.lastname: Brady
mesh_terms: D000328:Adult; D019970:Cocaine-Related Disorders / Q000188:drug therapy*; D003463:Cues; D003523:Cycloserine / Q000494:pharmacology*; D004311:Double-Blind Method; D005108:Extinction, Psychological / Q000187:drug effects*; D005239:Fear / Q000187:drug effects*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome
chemical_list: D003523:Cycloserine