Cocaine vaccine may be on the way

Vaccines that block the addictive rush of cocaine and amphetamines have been successfully tested in laboratory animals, scientists at California's Scripps Research Institute have announced.

The researchers said they hope to begin tests on humans later this year.

Cocaine and amphetamines are made up of extremely small molecules which travel undetected through the immune system. The vaccines developed by scientists successfully attached the drug molecules to proteins which were big enough for the animals' immune systems to recognize.

Once the molecules were bound with the proteins, antibodies blocked the drug in the bloodstream, before it reached the brain.

Researchers hope a cocaine vaccine could be used to treat drug overdoses.

The vaccines could also help people who want to drop their habit, researchers say. When a user feels the urge to take cocaine, the vaccine could be used to block the effects of the drug, gradually weaning people from its addictiveness.

Cocaine is quickly absorbed by the body, while amphetamines last longer. But cocaine can be quite addictive, with up to three-quarters of users who start treatment going back to the drug.

It is hoped that the vaccine would be particularly useful in the difficult, early stages of quitting the drug.

In the United States, more than 2 million people are believed to be in need of addiction treatment for cocaine.