A Vaccine for Cocaine

By Medical Discovery News

Feb. 4, 2012

A Vaccine for Cocaine

In the city that never sleeps, 274 people died due to cocaine abuse last year, according to the New York Post. While that figure has decreased by almost half in the past four years in New York City alone, scientists are attempting to create vaccines to end the addiction for millions of people around the world.

Despite the general belief that drug addiction is a moral failure rather than a physical disease, developing and producing inexpensive vaccines for addicts can reduce the hundreds of millions of dollars spent on their medical care and incarceration. Plus, it can help turn their lives around.

After 20 years of work by a number of different scientists, a cocaine vaccine is showing promising results. A trial study by an arm of the National Institutes of Health showed the vaccine reduced cocaine use in 38 percent of vaccinated patients. It works by stimulating the immune system to produce anti-cocaine antibodies that attack cocaine molecules in the blood, preventing them from traveling to organs such as the brain. If it’s not allowed in the brain, cocaine can’t induce a high. Therefore, over time, the patient may have a better chance at kicking the addiction.

Cocaine works by binding to receptors that normally would receive dopamine from another neuron. That leaves excess dopamine stuck between neurons, stimulating these neurons to fire repeatedly, creating the euphoria users feel. Some scientists believe this high makes cocaine the most addictive of drugs and is the reason why behavior therapy has not been effective in helping addicts stay off the drug.

A complication in developing the vaccine was the small size of the cocaine molecule, which does not generate a good immune response and high levels of antibodies. So, the idea was to link it to a large protein molecule. Researchers focused on an unlikely partner molecule – the cholera toxin B, a portion of cholera toxin that does not cause disease, but will stimulate the immune system to respond.

Researchers then attached this portion of the toxin to the cocaine molecule. Once the vaccine is injected, it induces production of antibodies that then circulate in the blood. When an addict uses cocaine, the antibodies bind to the molecule and prevent it from entering the brain.

The vaccine is a strict regimen of five shots over 12 weeks, a schedule that was challenging for many addicts to meet. In those that did, a third saw positive results. After two months, they needed a booster vaccine to maintain the proper level of cocaine antibodies. Researchers say the next step is to make the vaccine effective for a larger proportion of the people taking it, and to maintain the antibody level for longer than two months. It’s also clear that counseling and behavior therapy is necessary to control urges since the vaccine does not affect this physical component of the addiction.

Making a cocaine vaccine available to a wide range of people in both developed and developing countries would curb the damaging toll of this drug.

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