Effects of alprazolam, caffeine, and zolpidem in humans trained to discriminate triazolam from placebo

Drug Alcohol Depend. 2001 Feb 1;61(3):249-60. doi: 10.1016/s0376-8716(00)00145-9.


This study compared the discriminative stimulus effects of zolpidem, a nonbenzodiazepine hypnotic, to benzodiazepines. Eight participants learned to discriminate triazolam (0.35 mg/70 kg) from placebo. The discriminative stimulus effects, self-reported subjective effects, and performance effects of triazolam (0.05-0.35 mg/70 kg), alprazolam (0.25-1.75 mg/70 kg), zolpidem (2.5-35 mg/70 kg) and caffeine (75-525 mg/70 kg) were assessed under two-response and novel-response drug discrimination procedures. Under the two-response procedure, triazolam, alprazolam and zolpidem fully substituted for triazolam and caffeine did not. Under the novel-response procedure, triazolam and alprazolam substituted for triazolam and zolpidem partially substituted for triazolam. Zolpidem, but not triazolam or alprazolam, also produced some novel responding. Caffeine produced both placebo-appropriate and novel responding. The self-reported effects of triazolam, alprazolam and zolpidem were similar. Overall, zolpidem produced similar, but not identical, effects as the benzodiazepines.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adolescent
  • Adult
  • Alprazolam / pharmacology*
  • Analysis of Variance
  • Caffeine / pharmacology
  • Discrimination, Psychological / drug effects*
  • Discrimination, Psychological / physiology
  • Female
  • GABA Agonists / pharmacology*
  • GABA Modulators / pharmacology*
  • Humans
  • Male
  • Phosphodiesterase Inhibitors / pharmacology
  • Pyridines / pharmacology*
  • Triazolam / pharmacology*
  • Zolpidem


  • GABA Agonists
  • GABA Modulators
  • Phosphodiesterase Inhibitors
  • Pyridines
  • Triazolam
  • Caffeine
  • Zolpidem
  • Alprazolam