A Stop-Smoking Pill?
WEDNESDAY, July 26 (HealthSCOUT) -- Canadian researchers say they may have found a magic potion sought by millions: a pill that can make smokers glad to give up cigarettes.
The potion is a medication called methoxsalen, now marketed for skin conditions such as psoriasis. A group led by Dr. Edward Sellers at the University of Toronto says the drug also has the interesting ability to strengthen the activity of nicotine in the body.
That's good for smokers, says Sellers, because it means that smokers who take methoxsalen will get the same nicotine jolt from many fewer cigarettes. It's now accepted that cigarette smoking is an addiction caused by the body's craving for nicotine. Given with oral nicotine, methoxsalen helps keep the blood levels of nicotine up and could eliminate the desire to smoke.
"We think the strategy could help people cut down and make it easier to stop," says Sellers, who is professor of pharmacology, medicine and psychiatry at Toronto.
"It actually affects people's motivation to smoke. They will buy fewer cigarettes and smoke fewer of them,"says Jaylan Turkkan, chief of behavioral science research at the U.S. National Institute on Drug Abuse (NIDA), which helped finance the Canadian work.
Tobacco use is still the leading preventable cause of death in the United States, killing more than 400,000 people each year.
The road to methoxsalen started with an observation by Seller and his colleagues of a genetic defect, a deficiency of an enzyme called CYP2A6 that breaks down nicotine. That deficiency makes nicotine last longer in the body. People with CYP2A6 deficiency are less likely to start smoking and smoke less if they do, the Toronto groups reported two years ago in the journal Nature.
"Then we started looking for compounds that we could give to people that would be potent inhibitors of the enzyme," Sellers says. After screening more than 200 compounds, they came up with methoxsalen.
The compound has passed its first tests, the Toronto researchers report in this month's issue of the journal, Clinical Pharmacology and Therapeutics. In one test, 17 regular smokers were given different doses of methoxsalen and nicotine tablets. Measurements showed higher blood levels of nicotine in smokers that got the largest doses of methoxsalen, and those smokers also reported far less desire to smoke.
In a second test, smokers got either methoxsalen or a placebo, an inactive compound, with nicotine, and were allowed to smoke. Those who got methoxsalen smoked fewer cigarettes, had longer intervals between cigarettes and took fewer puffs.
The next step is a safety trial with a few patients, followed by large-scale effectiveness trial at a number of medical centers.
And while methoxsalen appears to be safe, Sellers does not recommend that smokers go out and try it to help them give up the habit because of possible side effects. "In high doses, it can sensitize the skin, so that one is more sensitive to sunburn," he says.
What To Do
Until a vaccine or drug treatment for smoking is developed, smokers should use all the available tools, such as nicotine patches and counseling, to give up the habit.
To help in the effort, check out this brochure from the Centers for Disease Control and Prevention that gives tips, key points and how to react in special situations.
And Committed Quitters has such features as a nicotine dependency quiz, a savings calculator, craving tips, stress relievers and more.