Author: Patricia Nicholson

About 19 per cent of Canadians – almost 5 million people – are smokers. Most of them have some motivation to quit, and many have tried, but relapse rates are high – especially without help.

Nicotine addiction can be viewed as a chronic medical condition, says Dr. Bernard Le Foll, head of the translational addiction research laboratory at the Centre for Addiction and Mental Health (CAMH). As with other addictions, most people will need some type of treatment or assistance to quit for good.

‘It is a true drug addiction, and requires long-term, repeated clinical interventions,’ Dr. Le Foll said during a presentation at Women’s College Hospital on May 5, 2010.

How tobacco addiction works

While some of the other 4,000 chemicals present in cigarette smoke contribute to its addictive effect, it is nicotine that smokers are addicted to. Nicotine binds to specific receptors (nicotinic acetylcholine receptors) in the central nervous system. This binding triggers an increase in the release of the dopamine, which gives a sensation of pleasure and is a secondary basis of addiction.

Dopamine is a neurotransmitter, a substance that helps relay information between nerve cells and other cells. When dopamine levels decrease between cigarettes, it leads to withdrawal symptoms such as irritability and stress, and the smoker craves nicotine in order to release more dopamine. Nicotine has a fairly short half-life of about two hours, so symptoms of withdrawal set in quickly.

The majority of smokers are motivated to quit, and 87 per cent of current smokers have tried to quit at least once. Most try to stop smoking without using any pharmacological quitting aids. However, only 5 per cent of long-term smokers quit without using any form of assistance, Dr. Le Foll said.

Eight days is the average time to relapse in people trying to stop smoking, but Dr. Le Foll noted that this is the nature of addiction, not a failure of the individual. Most people try to quit several times before they are successful.

Nicotine withdrawal syndrome is defined as having four or more of the following symptoms:

• dysphoric or depressed mood
• insomnia
• irritability, frustration or anger
• anxiety
• difficulty concentrating
• restlessness or impatience
• increased appetite

Help for smokers who want to quit falls into two main categories: pharmacological interventions and non-pharmacological interventions. The most successful approaches combine both types of treatment to address both the physical addiction and the behavioural aspects of smoking.

Non-pharmacological interventions don’t involve medications. They include doctors’ advice, self-help materials, individual and group counselling, and social support.

‘All of these increase the effectiveness of cessation,’ Dr. Le Foll said.

Current pharmacological approaches include nicotine replacement therapy and medications.

Help is available

Nicotine replacement therapy (NRT) is intended to maintain a nicotine level similar to smoking. On its own, NRT has been shown to be more effective than placebo, but it works best when combined with non-pharmacological approaches. It is available in patches, gums, lozenges and nasal spay.

Patches are long-acting, and are designed maintain nicotine levels throughout the day. They come in different strengths (7 milligrams, 14 milligrams and 21 milligrams) and provide a continuous dose of nicotine. Possible side effects include skin irritation from the patch itself, and sleep disturbances.

Gum and lozenges are short-acting, and provide nicotine when required. They come in 2 milligram and 4 milligram doses, and deliver that dose over a 30-minute period. They can be used as an immediate response to a craving to smoke, and may provide some of the oral gratification that smokers may miss when they quit. Side-effects can include upset stomach and hiccups from chewing the gum too fast.

It can be difficult to use nicotine gum as recommended, Dr. Le Foll said. It is meant to be chewed intermittently by biting down on it once and then ‘parking’ it between the teeth and cheek. This slow release can be challenging when dealing with cravings.

A nicotine inhaler is shaped like a cigarette, and provides a dose of nicotine through puffs that mimic smoking. Dr. Le Foll noted that the term ‘nicotine inhaler’ is a bit misleading, because it isn’t meant to be actually inhaled: the nicotine is absorbed in the mouth in small puffs. However, it may help to satisfy some the sensory or ritualistic aspects of smoking that people miss when they quit.

Depending on the needs of the person quitting, it is possible to combine different NRT products for the best results. Because different smokers have different needs, it is essential to adjust dosage based on withdrawal symptoms, Dr. Le Foll said.

Recent study results suggest that starting to use a nicotine patch before quitting may increase success rates, and that this approach appeared to be safe.

Other studies are investigating longer-term use of NRT. Although some smokers believe it is wise to stop using NRT as quickly as possible to avoid dependence on NRT products, Dr. Le Foll pointed out that NRT does not cause addiction.

‘They are already addicted,’ he said. ‘So you’re not causing an addiction to nicotine.’

Providing relief from cravings and withdrawal symptoms may keep quitters comfortable, while giving them time to create new habits and learn to be a nonsmoker.

Other pharmacological approaches

Beyond NRT, there are two medications that help smokers quit. Both require a prescription from a doctor.

Bupropion, sold under the brand name Zyban, was originally marketed as an antidepressant. It increases levels of dopamine and also affects norepinephrine (another neurotransmitter), as well as interfering with the nicotinic receptors. It not only doubles the chances of quitting successfully, but it may also help to minimize the weight gain associated with quitting.

The medication should be started one or two weeks before the quit date. Side-effects can include insomnia and dry mouth. There is also a small (one in 1,000) risk of seizure.

Varenicline, sold under the brand name Champix, is a newer drug that appears to work in two ways: it not only affects dopamine levels, but also prevents nicotine from binding to the nicotinic acetylcholine receptors.

‘It’s the most effective drug we have,’ Dr. Le Foll said. In studies, it showed better short-term and long-term results than either Zyban or placebo. However, Health Canada advises that it may be associated with adverse effects including mood changes, depression, suicide ideation and suicide. Although it is difficult to assess whether varenicline is the root cause of these symptoms because quitting smoking is also associated with these effects, it is important to monitor for these side-effects for safety.

People ready to quit smoking often have concerns about withdrawal, cravings, weight gain and other issues they may encounter as they become smoke-free. Dr. Le Foll noted that it’s very important to look at quitting not as a single step, but as a process with many physical and behavioural aspects.

When choosing which treatments to use to help them quit, people who want to stop smoking can consult with their doctor and discuss their best options based on patient preference, side-effects, safety, tolerability, cost and quit date, he said.