A drug used to combat high-blood pressure can save the lives of mice given lethal cocaine doses, and more work should be done to determine if the drug can help human overdose victims, researchers said.

Stanford University medical researchers said they found a "striking decrease" in overdose deaths in mice given propranolol - a "beta-blocker" drug that slows the heartbeat - before or shortly after large amounts of cocaine."If propranolol works in man as it does in mice, it will be a remarkable addition to the therapy of massive cocaine overdoses and save lives," Dr. Eugene Robin, the study's director, said in a telephone interview.

There is now no way to counteract the devastating effects of cocaine poisoning on the brain, said Robin, who estimates cocaine overdoses cause a "minimum of hundreds to more than hundreds of deaths" nationwide each year.

Although some doctors in the late 1970s reported success in treating overdose victims with propranolol, a 1981 study using dogs indicated the drug did not reduce the death rate from cocaine overdoses and such approaches were discouraged in humans.

In findings published in Annals of Internal Medicine, the Stanford team said its experiment was "more similar to human cocaine poisoning" than the 1981 study because the mice were injected with one large burst of cocaine, rather than the steady, intravenous dose given the dogs.

The researchers emphasized that "it is not at all clear that our results have any relevance to the treatment of human cocaine poisoning." But they added that the striking benefits found in mice strongly support further clinical trials to study the effectiveness of propranolol in humans.

In their study, the researchers found giving mice propranolol before cocaine dramatically reduced mortality, with just 23 percent of treated animals dying compared to 100 percent of the controls.

The anti-hypertension drug also produced "highly significant" results when it was given shortly after cocaine overdoses, researchers said.