Champix promises to prevent nicotine from creating that 'feelgood' sensation, with the aim of reducing a person's desire to smoke.

When nicotine is inhaled, it attaches to receptors in the brain. These receptors send a message to a part of the brain which releases a natural feelgood chemical called dopamine.

But dopamine's effects are only felt for a limited time. To maintain that sensation, people need another cigarette, and another.

Chris Westinghouse from Pfizer Australia, who manufacture the drug, says: 'Champix binds to the nicotine receptors in the brain and decreases the craving and withdrawal symptoms associated with quitting smoking. It reduces the pleasure obtained from cigarettes if the person taking it smokes.'

In clinical trials, people who took Champix were almost four times more likely to quit smoking after 12 weeks of treatment, compared to people who took a placebo. A year after using the treatment, people who took Champix were three times more likely to stay non-smokers.

Is it safe?
While the drug's manufacturers claim its most common side-effects are nausea, unpleasant dreams and insomnia, less commonly Champix has also been linked to depression and even suicidal thoughts.

In the UK, a 36-year-old father of two was found hanged shortly after completing a 13-week course of Champix and a 39-year-old TV editor killed himself after starting to use the drug to break his smoking habit.

Since the drug's launch in 2006, there have been some 2000 reports of adverse reactions in the UK alone, including more than 50 instances of people having suicidal feelings.

In Australia, Champix is available via prescription only (for about
$30 for the first month under an authority script). People who have a concession health card can purchase a 12-week course for $10. However, doctors warn the drug may not be suitable for anyone with a history of depression.

Suzie Stillman, deputy director of Quit Victoria, says: 'Further investigation needs to take place. In the interim, it's important GPs are mindful who they prescribe this drug to.'

Chicken and egg
Other doctors claim it's not the treatment per se which causes
the depression. According to Ian Hickie, professor of psychiatry at the Brain & Mind Research Institute at the University of Sydney, people who smoke are more likely to be depressed, and therefore more likely to become depressed upon quitting.

'People may know they're vulnerable to depression due to prior experience of the illness or because there's a family history of it,' Professor Hickie explains.

'Given that many smokers have underlying depression, it's not surprising most medications used to assist with quitting smoking have been associated with depression and, more rarely, with suicidal thoughts. These are situations that need to be monitored closely by the prescribing doctor,' he adds.

But smoking is still worth trying to give up, even if you're susceptible to depression, according to a study from the University of Helsinki in Finland. The study found persistent smokers are more prone to depression than non-smokers.

What's more, they're more likely to see their depression increase when they stop smoking. However depression levels dropped if they stayed away from cigarettes.

Professor Hickie agrees that when the depression is treated
with standard antidepressants and behavioural therapy, he has seen many cases of smokers who are 'finally able to kick the habit'. 

Need help to quit smoking?
Call the Quitline on 137 848, or go to www.quit.org.au

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