Rat Tests Find Cocaine Highly Toxic, Addictive

CHICAGO —  Laboratory animals given free access to cocaine, a drug used by as many as 24 million Americans, died at almost three times the rate of those given access to heroin, a new study found.

The study, reported today in the Journal of the American Medical Assn., supports other findings that cocaine is more addictive and toxic than heroin.

Scientists implanted tubes in the necks of 23 rats so that each animal could press a lever in its cage to self-administer a set dose of drug into its bloodstream. The rats were divided into two groups, one for each drug.

90% Mortality Rate

After 30 days, 11 of the 12 cocaine-using rats were dead, a mortality rate of 90%, compared to only four of the 11 heroin-using rats, a mortality rate of 36%, said the researchers, Michael A. Bozarth and Roy A. Wise of Concordia University in Montreal.

Rats using cocaine lost more weight and suffered more marked declines in health than the heroin-using rats, the researchers said.

Unlimited Access

“The fact that the number of fatalities following unlimited access to cocaine was over twice that following unlimited access to heroin has obvious implications for human drug abuse,” the study said.

“Cocaine produces a more tenacious dependency,” said Dr. Ronald K. Siegel, a pharmacologist at the UCLA School of Medicine. “With unlimited access, you will reach toxic levels faster.”

24 million Users

Government estimates put the number of U.S. cocaine users at 5 million to 8 million, according to Siegel, but he said his studies indicate that 24 million would be a “conservative” estimate.

At the end of 1984, 400,000 users were believed to need clinical attention, and about one person died from cocaine use per day, he said.

“Cocaine use . . . is considered by many to be a relatively safe habit,” the researchers said, explaining that relatively few deaths are attributed to it because availability is limited.