Toxicity associated with long-term intravenous heroin and cocaine self-administration in the rat

JAMA. 1985 Jul 5;254(1):81-3.


Laboratory rats were given unlimited access to intravenous cocaine hydrochloride or heroin hydrochloride. Animals self-administering cocaine quickly developed a pattern of episodic drug intake, with periods of excessive cocaine self-administration alternating with brief periods of abstinence. Subjects allowed continuous access to intravenous heroin showed stable drug self-administration, with a gradual increase in daily heroin intake over the first two weeks of testing. The general health of the animals became markedly different: those self-administering heroin maintained grooming behavior, pretesting body weight, and a good state of general health; rats self-administering cocaine tended to cease grooming behavior, to lose up to 47% of their pretesting body weight, and to show a pronounced deterioration in general health. The mortality rate for 30 days of continuous testing was 36% for animals self-administering heroin and 90% for those self-administering cocaine. These results suggest that cocaine is a much more toxic compound than heroin when animals are given unlimited access to intravenous drug.

Publication types

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

MeSH terms

  • Animals
  • Body Weight / drug effects
  • Cocaine* / administration & dosage
  • Grooming / drug effects
  • Heroin / administration & dosage
  • Heroin Dependence / mortality*
  • Humans
  • Infusions, Parenteral
  • Male
  • Rats
  • Self Administration
  • Substance-Related Disorders / mortality*


  • Heroin
  • Cocaine