Hydromorphone-naloxone combinations in opioid-dependent humans under a naloxone novel-response discrimination procedure

Exp Clin Psychopharmacol. 1998 May;6(2):169-78. doi: 10.1037//1064-1297.6.2.169.


Naloxone-hydromorphone combinations were tested in participants trained to discriminate naloxone from placebo under a novel-response drug discrimination procedure while maintained on methadone. Naloxone alone produced dose-related increases in naloxone-appropriate responding, little or no "novel"-appropriate responding, and increases in opioid antagonist adjective ratings (n = 5). Hydromorphone alone produced dose-related increases in novel-appropriate responding, little or no naloxone-appropriate responding, and increases in opioid agonist adjective ratings (n = 6). When combined with naloxone, hydromorphone produced dose-related decreases in naloxone-appropriate responding and antagonist adjective ratings (n = 6). These findings are consistent with nonhuman data and suggest that this procedure may be useful as a human laboratory model of opioid withdrawal.

Publication types

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

MeSH terms

  • Adult
  • Discrimination Learning / drug effects*
  • Dose-Response Relationship, Drug
  • Female
  • Humans
  • Hydromorphone / administration & dosage*
  • Male
  • Methadone / therapeutic use
  • Naloxone / administration & dosage*
  • Opioid-Related Disorders / drug therapy*
  • Opioid-Related Disorders / psychology


  • Naloxone
  • Hydromorphone
  • Methadone