v4n3 - Breaking a Bad Habit

CURE, Fall 2005, Volume 4, Issue 3

Of the 45 million smokers in the United States, 70 percent want to quit. Many people relapse when trying to quit smoking, but support and cessation aids help increase long-term success rates.

Nicotine-replacement therapy (NRT) uses a step-down approach with different nicotine strengths. Nicotine gum, nasal spray or the lozenge Commit® suppress immediate cravings by releasing the addictive chemical for quick absorption into the bloodstream. Nicotine patches release the chemical over a longer period of time. The Straw™, currently in phase III trials, contains small beads of nicotine that are ingested for immediate relief. The disposable plastic straw delivers as much nicotine as other NRTs.

Zyban® (bupropion), known as the antidepressant Wellbutrin®, is the only non-nicotine FDA-approved drug for smoking cessation. Nicotine withdrawal symptoms are similar to depression, making Zyban, and other antidepressants used off-label, effective for smoking cessation. Zyban combined with NRT may improve quit rates. A major study showed that smokers using both Zyban and nicotine patch had a higher one-year continuous quit rate (23 percent) compared with either treatment alone (18 percent and 10 percent, respectively). Common side effects of Zyban include insomnia, nausea and headache.

Another non-nicotine drug called varenicline helped about half of smokers quit compared with Zyban in a phase II clinical trial. Varenicline, now in phase III, targets receptors in the brain to block the pleasure of smoking and reduce nicotine cravings and withdrawal symptoms.

Acomplia™ (rimonabant), also in phase III testing, suppresses cravings for food and narcotics in the brain’s hypothalamus by blocking receptors in the brain. Recent research showed that nearly a third of smokers quit for a longer period of time than smokers trying to quit without taking the drug. Currently under FDA review, Acomplia will likely gain approval for treating obesity in 2006.

A novel option for combating nicotine addiction uses the body’s immune system. Typically, nicotine travels from the lungs into the bloodstream and enters the brain after crossing the blood-brain barrier. Nicotine binds to nerve cell receptors and causes a stimulatory response. A vaccine called NicVAX™ stimulates production of antibodies that bind to nicotine molecules, preventing them from crossing the blood-brain barrier. The “high” normally caused by nicotine does not occur, making it easier for people to quit. In a phase II test, NicVAX lowered nicotine levels in the brain 64 percent.

Studies show that combining cessation treatment with social or behavioral support carries the best chance for long-term success. Visit www.smokefree.gov for more on how to quit smoking.