(iVillage Total Health) - People addicted to cocaine and methamphetamines may have a new weapon in the fight to win their drug dependence battle: Researchers have developed vaccines to help overcome addiction to the stimulants.
Just as children receive chickenpox vaccines to avoid the virus that causes skin rashes, recovering drug addicts may be able to take vaccines—and booster shots—to block the stimulation caused by cocaine and methamphetamine (or meth).
Cocaine is a highly addictive stimulant drug made from the leaves of the coca plant. It elicits feelings of euphoria, excitement, restlessness and well-being. Methamphetamine is another extremely addictive stimulant that enhances mood and body movement. It may also be called "ice," "crystal" or "speed." Both act on the central nervous system and cause chemical changes in the brain.
According to a 2004 study conducted by the U.S. Department of Health and Human Services Substance Abuse and Mental Health Services Administration (SAMHSA), about 2 million people reported using cocaine in the month prior to the study.
The new vaccines work by prompting the body's immune system to produce antibodies that attack the cocaine and meth drug molecules in the bloodstream—before they reach the brain. This blocks the reactions that lead to dependency. The vaccines are not preventive measures, but are designed for patients already addicted to cocaine and meth.
"The vaccine slowly decreases the amount of cocaine that reaches the brain," Dr. Thomas Kosten, the study's lead investigator, said in a press release. "It's a slow process, and patients do not go through any significant withdrawal symptoms."
Researchers from the Baylor College of Medicine and Yale University School of Medicine developed the vaccines, but they stressed that the shots are not cure-alls for drug abuse and addiction. Relapse into cocaine and meth use may still be possible after the vaccine, especially if users return to old habits and fail to address underlying problems that may have led to the initial drug use.
"This is not a stand-alone treatment," Kosten added. "There is a reason drugs were used in the first place, and that needs to be dealt with either through counseling or behavioral therapies."
Neither vaccine has been approved by the U.S. Food and Drug Administration (FDA) for use in humans. The cocaine vaccine—called TA-CD—involves a series of injections administered over a three-month period. If needed, booster shots may be given every four to eight weeks.
Researchers studied the effects of the cocaine vaccine on 22 people—nine cocaine-dependent participants who were observed for potential to relapse and 13 participants who were also cocaine dependent but were assessed for likelihood of abstaining from drug use. The first group had to be drug free for at least two weeks prior to the start of the study as verified by urine testing. The second group was not required to have urine testing.
The groups received a series vaccinations ranging in total dosage from 300 up to 2,000 micrograms (mcg). Participants showed signs of cocaine antibodies in their blood about 70 to 90 days after vaccination and the antibodies lasted for at least six months. Eight of the participants received booster shots 15 to 18 months after the initial vaccination and all tested positive for cocaine antibodies two to four weeks later.
Three out of four people in the first study group—those who were assessed for relapse into drug use—stopped using cocaine during the 12-week study period. However, all of them had relapsed after 12 months when their antibody levels had declined.
A majority (58 percent) of the second group—those observed for likelihood of stopping cocaine use after vaccination—was able to abstain from cocaine use during the 12-week study period and 42 percent of them were still drug-free after six months.
The meth vaccine is still under development, but studies showed its effectiveness was similar to the cocaine vaccine, researchers said.
"We are impressed with these results which, although on a comparatively small number of subjects, are particularly significant as a number of addicts receiving the TA-CD vaccine were able to remain abstinent during the study periods," Bridget Martell, one of the researchers, said in a press release.
The study results were presented during the 66th annual scientific meeting of the College on Problems of Drug Dependence held June 12-17 in Puerto Rico. The study was funded by a grant from the National Institute of Drug Abuse.
Copyright 2007 iVillage Total Health.