Modification of ethanol's reinforcing effectiveness in rhesus monkeys by cocaine, flunitrazepam, or gamma-hydroxybutyrate

Gail Winger, Chad M. Galuska, Steven R. Hursh

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


Background: Although ethanol is frequently used in combination with other psychoactive drugs, the behavioral and pharmacological reasons for this form of polydrug abuse have not been well described. Materials and methods: Rhesus monkeys with indwelling intravenous catheters produced intravenous injections of ethanol (50, 100, or 200 mg/kg/inj), flunitrazepam (0.001-0.03 mg/kg/inj), cocaine (0.01 or 0.03 mg/kg/inj), or combinations of ethanol and these drugs or gammahydroxybutyrate (GHB) (1.0 or 3.2 mg/kg/inj) by lever pressing according to a fixed-ratio schedule. The response requirement for each drug or drug combination was increased across sessions (10, 32, 100, 320, or 1,000). The dependent variables were rates of responding maintained by the drug or drug combination and the elasticity of drug demand when consumption was expressed as a function of price. Results: Elasticity (Pmax) values for each drug varied among the monkeys but retained the same rank order for the monkeys, suggesting a fundamental difference in the animals' apparent sensitivities to the reinforcing effects of the drugs. Combining ethanol with the other drugs did not increase their reinforcing effectiveness. GHB (ineffective in previous studies) did not modify ethanol's reinforcing effects; demand functions for the combination of ethanol and flunitrazepam were slightly less elastic than for ethanol alone, but no different from that for flunitrazepam alone; adding ethanol to cocaine detracted from the reinforcing effectiveness of cocaine. Conclusions: The hypothesis that use of ethanol in combination with sedative and stimulant drugs is due to an ability of ethanol to enhance the reinforcing effects of these drugs is not supported.

Original languageEnglish (US)
Pages (from-to)587-598
Number of pages12
Issue number4
StatePublished - Sep 2007


  • Ethanol-drug combinations
  • Reinforcing effectiveness
  • Rhesus monkeys

ASJC Scopus subject areas

  • Pharmacology


Dive into the research topics of 'Modification of ethanol's reinforcing effectiveness in rhesus monkeys by cocaine, flunitrazepam, or gamma-hydroxybutyrate'. Together they form a unique fingerprint.

Cite this