DRUG TESTED TO EASE CRAVINGS FOR COCAINE

European scientists have developed a drug that uses a promising new
approach to ease cravings for cocaine in addicted rats.

BP 897 is the first drug to target the "conditioning" effect of cocaine, or
the way, for example, that the mere sight of a street corner where the
addict used to buy cocaine can evoke a craving, said Maria Pilla, a
psychologist at the University of Cambridge in England who led the study.

The only other drugs available either mimic cocaine so much that they
themselves can become addictive, or block its effects so well that addicts
overload on cocaine to deal with the pangs of withdrawal.

Full-scale tests in humans could begin as early as next year.

The study was published in Thursday's issue of the journal Nature.

BP 897 eases the cravings associated with cocaine withdrawal by mildly
stimulating the brain while regulating dopamine levels, a brain chemical
that can create intense pangs for the narcotic.

This is the first drug that creates a balance in the brain to help addicts
deal with withdrawal, said Gary Aston-Jones, a University of Pennsylvania
neuroscientist who co-wrote an accompanying commentary.

Cocaine is particularly hard to kick because of its ability to "condition"
users and evoke cravings the way an old song or a whiff of perfume can
trigger a flood of memories. An addict in rehab can get a craving for
cocaine just by returning to the room where he used to snort it.

Pilla and her colleagues reported that BP 897 helped rats addicted to
cocaine break away from the effects of conditioning.

The researchers first trained rats to give themselves cocaine through a
catheter by pulling a lever. A light was rigged to go on every time the
rats did this, conditioning them to associate the light with the high.

Later, the rats were taken off the cocaine. When researchers continued to
turn the light on, the rats were reminded of the drug and pulled the lever.

"The rat is probably going through an intense craving at this point," said
Pierre Sokoloff, a French researcher who worked on the project at the
National Institute for Health and Medical Research in Paris. "This is a
state that simulates withdrawal."

But once scientists gave them BP 897, the rats sought cocaine only half as
much as before.

Although it hasn't been tested with other addictive drugs, BP 897 might
also be effective in treating heroin or tobacco addiction because they,
too, condition addicts, said Jonathan Druhan, an expert in drug addiction
at the University of Pennsylvania.