Varenicline Tartrate for Smoking Cessation
Varenicline tartrate was discovered and developed by Pfizer, Inc. specifically to help people quit smoking. Marketed as Chantix™, this prescription medicine works on two levels.
First, Chantix partially activates sites in the brain known as nicotinic acetylcholine receptors that are affected by nicotine. This gives the person quitting mild nicotine-like effects and eases symptoms of nicotine withdrawal.
Second, Chantix has the unique ability to neutralize the effects of nicotine if a person smokes while using this drug. Let's take a closer look.
Nicotine is Highly AddictiveNicotine provides its user with an almost immediate "kick" of euphoria that is the result rapidly changing brain chemistry beginning within 7 seconds of the first puff on a cigarette. Nicotine attaches to nicotinic receptors which affect functions such as breathing and heart rate. That process in turn triggers the release of dopamine, the neurotransmitter thought to be responsible for reinforcing the pleasure/reward associations people have with smoking.
How Nicotinic Acetylcholine Receptors WorkThe nicotine molecule is very similar in shape to the neurotransmitter acetylcholine, which affects many bodily functions, including breathing, heart rate, learning and memory. Acetylcholine also affects other neurotransmitters that have influence over appetite, mood, and memory. In the brain, nicotine binds with nerve cell receptor sites in places where acetylcholine would, creating the same effects.
Chantix and Nicotinic ReceptorsChantix works by partially activating a specific type of nicotinic receptor called alpha4beta2 nicotinic receptors. The effect of this on the user is similar to a low to medium dose of nicotine. In this way, Chantix helps to relieve symptoms of nicotine withdrawal that people experience when they quit smoking.
Nicotine and Dopamine
Nicotine activates the same reward system as do other drugs of abuse such as cocaine or amphetamine, although to a lesser degree. Research has shown that nicotine increases the level of the neurotransmitter dopamine, a chemical in the brain responsible for feelings of pleasure and well-being.
The acute effects of nicotine wear off within minutes, so people continue dosing themselves frequently throughout the day to maintain the pleasurable effects of nicotine and to prevent withdrawal symptoms.
Chantix and DopamineOnce in place, Chantix blocks nicotine from activating alpha4beta2 nicotinic receptors, which in turn prevents dopamine stimulation in the brain. This gives the person quitting a critical advantage. Should he/she decide to smoke while using this drug, there is no nicotine "feel good" rush, and the smoking experience is flat; dull. Smoking then becomes unfulfilling, and quitting hopefully, easier to accomplish.
Is Chantix Effective?Six clinical trials involving 3659 chronic cigarette smokers were used as a basis for the effectiveness of Chantix as a therapy for smoking cessation.
Five of the trials were randomized, placebo-controlled studies, and showed that Chantix was more effective than a placebo to help people quit smoking. In two of the five trials, people using Chantix therapy (22 percent) were more successful at quitting smoking than those using Zyban (bupropion hydrochloride) (16 percent) as a quit smoking aid. For those taking a placebo, abstinence at the one year mark was approximately 8 percent.
While a 22 percent success rate may not seem like great odds, keep in mind the sheer number of people who are addicted to nicotine and dying because of it today. Globally, smoking-related disease causes 4 million deaths every year. Put another way, tobacco claims a human life every 8 seconds somewhere in the world. A drug that has the potential to help 22 out of every 100 people using it quit smoking is impressive indeed.
We are fortunate to live in a time when advances in medicine offer smokers more choices than ever before to quit smoking successfully. Nicotine addiction kills, plain and simple, and drugs like Chantix give hope to those who might not have been able to quit smoking otherwise.
- Medication Guide Chantix™ (varenicline) Tablets. U.S. Food and Drug Administration. Accessed on 18 May 2010 http://www.fda.gov/downloads/Drugs/DrugSafety/ucm088569.pdf.
- FDA Approves Novel Medication for Smoking Cessation. 11 May 2006. U.S. Food and Drug Administration. Accessed on 16 Oct 2006 http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/2006/ucm108651.htm.
- "Chronic Disease - Tobacco-At-A-Glance." Targeting Tobacco Use: The Nation’s Leading Cause of Death. 10 July 2006. Centers for Disease Control and Prevention. Accessed on 16 Oct 2006 www.cdc.gov/nccdphp/publications/aag/osh.htm.