Discrimination of butorphanol and nalbuphine in opioid-dependent humans

Pharmacol Biochem Behav. 1990 Nov;37(3):511-22. doi: 10.1016/0091-3057(90)90021-9.


The purpose of the study was to evaluate the agonist and antagonist stimulus properties of the mixed opioid agonist antagonists butorphanol and nalbuphine in opioid-dependent subjects. Opioid-dependent volunteers (methadone 30 mg/day, PO) were trained in a three-choice drug discrimination procedure to discriminate between the effects of saline (2 ml), hydromorphone (10 mg/70 kg) and naloxone (0.15 mg/70 kg) administered IM. Subjects earned monetary reinforcement for correctly identifying the training drugs by letter code. Other subjective, behavioral and physiological measures were also collected. Hydromorphone and naloxone increased drug-appropriate responses and other characteristic subjective effects measures. Butorphanol and nalbuphine produced increases in naloxone-appropriate discrimination responding and in those subjective effect measures increased by naloxone. Butorphanol produced greater than 80% naloxone-appropriate responding at 1.05 mg/70 kg; nalbuphine produced 100% naloxone-appropriate responding at 2.1 mg/70 kg. Neither butorphanol nor nalbuphine showed opioid agonist-like effects in these subjects maintained at moderate levels of physical dependence. In opioid-dependent subjects, the stimulus effects of butorphanol and nalbuphine are antagonist-like.

Publication types

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

MeSH terms

  • Adult
  • Behavior / drug effects
  • Blood Pressure / drug effects
  • Body Temperature / drug effects
  • Butorphanol / pharmacology*
  • Discrimination, Psychological / drug effects*
  • Generalization, Psychological / drug effects
  • Humans
  • Hydromorphone / pharmacology
  • Male
  • Methadone / pharmacology
  • Middle Aged
  • Nalbuphine / pharmacology*
  • Naloxone / pharmacology
  • Psychomotor Performance / drug effects
  • Pupil / drug effects
  • Receptors, Opioid / drug effects*


  • Receptors, Opioid
  • Naloxone
  • Nalbuphine
  • Hydromorphone
  • Butorphanol
  • Methadone