Smokers may be much more likely to stop by using a new drug called rimonabant — and quit without unusual weight gain. Now a Utah research firm is enrolling patients for a new clinical study of the drug and its effect on smoking.
The findings of a recently concluded large clinical trial of rimonabant were presented to a meeting of the American College of Cardiology by researchers from the University of Cincinnati College of Medicine in March. The cardiology group has keen interest because of the impact smoking has on heart disease. It is estimated that a third of smokers will die from a tobacco-use-related disease.
Radiant Research 64th South will begin enrolling about 55 patients in another trial of the drug, said Dr. James Ferguson, executive medical director.
"When I first heard about this, I was very skeptical," he said, describing a new class of drugs that blocks receptors in the human brain that respond to the active ingredient in marijuana.
The brain has "many little chemicals" and scientists don't understand everything they do. The brain even makes its own opiates, called endorphins, which make one feel good, like the "high" someone can get while running. About six years ago, researchers found the same kinds of receptors for the active ingredient in marijuana and started wondering what its real role is, since the brain clearly doesn't produce it to create a craving for the illegal drug, Ferguson said.
Researchers studied it to see if it would help schizophrenia. It didn't. Because people who smoke the substance get the munchies, they looked at that and found it may be involved in appetite and weight control by affecting the CB1 receptor and reducing the craving for food.
Early research has shown no abuse potential and no significant side-effects, he said.
Because marijuana and the CB receptor are tied into the brain-reward system, the researchers theorized it might block the effects of nicotine, at least indirectly.
Nicotine stimulates the dopamine receptors. When participants in the clinical trial used rimonabant, they had a high nicotine quit rate and markedly decreased cravings, though cravings didn't stop all together.
"None of these things are on-off switches," Ferguson said. "There are too many pathways. But if we can blunt cravings and combine it with a stop-smoking program . . . "
That's what the new study will test. Over the 12-week course of the clinical trial, which is free, participants will receive about 20 minutes of counseling each visit on topics like craving, appetite and social situations that trigger the urge to smoke. To stop smoking, someone must deal with the whole psychological side of addiction, Ferguson said.
Most important is how long someone stops smoking, he said, and rimonabant has a good record out to two years later. "That's a significant health intervention. If you stop for three months, in the scope of things, that doesn't really matter a lot. If you've had a couple of years to work on (the psychological issues on which counseling is offered), the chances of lifelong abstinence are better."
Participants must have general good health and can't be using a substance of abuse, such as marijuana. Alcohol use should be very limited or nonexistent. And the participant has to be willing to quit smoking and to sign a "quit-date" agreement.
Initially, participation means a weekly appointment once a week, during the day, which will taper off as the study progresses. It's a blind study, so some participants will receive a placebo.
For more information, call 261-9093.