Chantix – Project Smoking Cessation!

Hello my friend,

I trust you’re having a wonderful beginning of the year! Today’s blog is directed at those of your kith and kin who have resolved to quit smoking, and may require some pharmaceutical help to boost their resolution.

The chief drug in cigarette smoke is nicotine, which has addictive characteristics similar to cocaine and heroin. How does nicotine make you feel good? Let’s look at the neurochemical mechanisms involved.

Acetylcholine (ACh) is a principal neurotransmitter in our body, both in the central and peripheral nervous systems. In the central nervous system, Ach is involved with memory and learning (damage to the system that releases Ach is likely involved with Alzheimer’s disease), as well as with arousal and reward pathways. In the peripheral nervous system, Ach activates muscles, and regulates respiration, perspiration, pupil dilation and constriction, digestion, urination and sexual arousal.

Ach produces its effect by stimulating Ach receptors. There are two kinds of Ach receptors, the nicotinic receptors and the muscarinic receptors, named for the fact that the plant alkaloid nicotine has an affinity for the former receptors and another plant alkaloid muscarine has an affinity for the latter receptors.

So, when you smoke a cigarette, how does nicotine act? When you inhale a puff, the nicotine in the smoke is absorbed in the lung and reaches the brain within a few seconds. It binds to the nicotinic receptors in the brain and activates several neurotransmitters in the brain, including dopamine that leads to euphoria, relaxation and later, addiction. Nicotine also binds to nicotinic receptors in the adrenal medulla, stimulating the release of adrenaline leading to increased pulse rate and blood pressure, quicker breathing and increased glucose release into the blood by the liver. This can lead to cardiovascular disease.

By virtue of its increased cholinergic activity, nicotine inhibits programmed cell death, one of the processes by which the body destroys damaged and pre-cancerous cells. Other ingredients of cigarette smoke can be carcinogenic or cancer-producing.

Obviously, it’s a good idea to stop smoking. In recent times, there have been several aids to help us achieve this goal. Chantix (generic name varenicline, it’s known by brand name Champix in Europe) is the most effective prescription medication available since 2006 to help us stop this habit. It comes in the form of tablets, approved for use for a period of 12 weeks. If, during that time period, the individual stops smoking, it has been approved for an additional 12 weeks.

Chantix is a nicotinic receptor partial agonist. It is a derivative of the natural plant alkaloid cytisine. It is a partial agonist of some kinds of nicotinic receptors, which means it binds to the receptor and produces effects that are not quite the entire spectrum of effects produced by nicotine at that receptor. By so doing, it decreases one’s cravings for nicotine and reduces the feel-good euphoria and relaxation produced by the drug. A year-long scientific study shows successful smoking cessation in 23 per cent of the subjects in the study.

Any negatives? Yes. In July 2009, the FDA required its strongest warning, the “black box warning” to be issued with Chantix, warning of possible side-effects of depression, and suicidal thoughts and actions, due to various reports of the same.

On the other hand, a study published in the British Medical Journal in October 2009 studied 10,973 individuals who were using Champix to quit smoking and found insignificant increase in depression or suicidal ideation or actions. This was part of a larger cohort study (also called panel study) of 80,660 individuals who were using various methods of smoking cessation. However, as we dig into the details of this study, the authors do list 18 episodes of self-harm in the 10,973 subjects. Also, the data was collected from a large population of general practitioners in the U.K. All of the deaths did not have full death certificates, so the number of suicides were likely under-reported, per the authors’ admission. In spite of these limitations, thorough statistical evaluation still indicates no significant increase in depression, self-harm or thoughts of the same.

Here are my thoughts. Every drug out there, yes even routine over the counter medication like Advil or ibuprofen, has side effects, some of which can be fatal. We still continue to use these meds as and when necessary. The medical establishment and the citizen evaluates and balances the pros and cons of the medicine and use it as needed.

We apply the same standard to Chantix. The health advantages of smoking cessation are well worth the risks of using pharmaceutical aid to do so. If while using the drug, we feel not-so-good thoughts and feelings, we inform our doctor. The doctor can take us off the medication if that’s the best course of action.

I wish you the best with your resolutions. Until next time, my friend, I wish you good health.

Dr. Ajit Damodaran

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