 Zyban: In Monday's Health section, an article on quitting smoking said that the smoking-cessation medication Zyban might act by blocking the brain chemicals norepinephrine and dopamine. In fact, Zyban is believed to act by blocking the reuptake of norepinephrine and dopamine into nerve cells. This would enhance, not block, activity of the two chemicals. —
Most smokers try to stop multiple times before finally kicking the habit, and fewer than 10% will succeed in permanently abstaining without medicine or counseling.
Nearly 1 in 5 Americans are at least occasional smokers, risking cancer, heart disease and a shortened life span -- and costing the nation more than $193 billion annually, including healthcare costs and decreased workplace productivity among smokers, the CDC says. They continue to light up even as employers increasingly charge higher health insurance premiums for smokers.
Nicotine's hold on the brain is not easily broken, as the struggles of President Obama -- a very self-disciplined man by all accounts -- illustrate. Many would-be quitters, like the president, relapse when the appeal of nicotine is simply too strong.
For the vast majority who can't go it alone, researchers and pharmaceutical companies are developing new treatments that can help smokers stub out that final butt. And they are finding newer, more effective ways to use nicotine-replacement therapies such as gum and patches.
Zyban
Zyban, the commercial name for bupropion, is a smoking cessation aid that contains no nicotine. It was first marketed as the antidepressant Wellbutrin by Brentford, England-based GlaxoSmithKline. Unexpectedly, smokers using the pill reported that their cigarette cravings decreased. After three studies confirmed the effect, the company in 1997 repackaged bupropion as Zyban.
Chantix
Varenicline, marketed in the U.S. since 2006 as Chantix by New York-based Pfizer Inc., was the first new smoking-cessation drug in nearly a decade.
The drug works by attaching to the brain's nicotine receptors, preventing nicotine from stimulating them. (Since it interferes with the brain's ability to sense nicotine, it is not recommended in combination with nicotine-replacement therapies.) Varenicline also dampens the symptoms of nicotine withdrawal by partially activating the nicotine receptors. "It's like taking out a 100-watt light bulb and putting in a 60-watt light bulb," Hughes says. The most common side effect is nausea. Some patients also report vivid dreams.
A 2007 Cochrane report examined nine studies on varenicline, encompassing more than 7,000 subjects. Overall, varenicline doubled or tripled quit rates compared with inactive placebos. It also worked somewhat better than the nicotine patch or bupropion, making it a top choice among many physicians and patients.
But Chantix has also raised concerns. During the fourth quarter of 2007, the FDA received nearly 1,000 reports of serious injury (such as accidents, falls, heart arrhythmias or seizures) or psychological disturbances (such as hostile or suicidal thoughts) for people taking varenicline.
No study has analyzed these side effects in detail, so it is not clear how many of them were caused by the drug. "There's reason to worry, but there's not enough data to understand how much to worry, or who to worry about," Shiffman says.
The FDA advises patients to tell their doctors about any history of psychiatric illness, and says doctors and family members should monitor Chantix users for changes in mood or behavior. The Federal Aviation Administration has banned pilots and air traffic controllers from taking the drug. But most doctors feel that Chantix is safe and are comfortable prescribing it to the majority of patients.
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