Sunday, September 6, 2009

Chantix works on a smoker's brain

Varenicline is a smoking cessation drug developed by Pfizer. It is sold under the brand name Chantix in the US and Champix in Canada and Europe. And, thousands of users consider its use a recipe for disaster.

It is thought to work by reducing the smoker’s urge to smoke and by relieving craving and withdrawal symptoms because it is apparently capable of mimicking the effects of nicotine to some degree. And, by binding to nicotine receptors in the pleasure centre in the brain, it can also reduce the pleasure derived from smoking.

The Chantix website explains: “CHANTIX is different from most other quit-smoking products. It targets nicotine receptors in the brain, attaches to them, and blocks nicotine from reaching them. By activating these nicotine receptors, it is also believed that CHANTIX causes less dopamine – compared to nicotine – to be released.”

It is believed that . . . ? Are they really saying they don't know? Some might consider that somewhat akin to a chemically induced frontal lobotomy for smokers.

Since its introduction to the market, there have been a continually growing number of complaints about this latest “wonder drug” from the pharmaceutical industry.Thousands of people have complained of serious side-effects associated with the drug, the most disturbing of which is suicidal ideation, which may have resulted in 100 or more actual suicides.

The US FDA (Food and Drug Administration) recently advised the manufacturers of the smoking cessation drug to carry a suicide warning. But, Chantix, despite concerns of the FDA and the public, has not been pulled from the market.

In many respects, it is getting the same kid-glove treatment afforded another smoking cessation drug, Zyban, and an anti-depressant medication, Wellbutrin, both of which are distributed by Glaxo-Smith-Kline under the trade name bupropion. Zyban has also been implicated as the cause of serious side-effects, including suicide, among users.

The drug manufacturers are permitted to keep marketing the drugs in the US by simply including a cautionary “black box” warning (the FDA's most serious caution) on the packaging and instructions for use, advising users of the possible side-effects.

The warning, of course, does little to reduce the potentially life-threatening side-effects of Chantix (or Zyban). It does, however, reduce legal liability for Pfizer, the manufacturer of the drug. They can now claim that they followed the directives of the FDA regulators (or Health Canada, or Britain's NHS, etc.) and warned consumers of the potentially serious side effects of the smoking cessation drug.

But, Pfizer needed FDA approval to market the drug in the first place. And, to obtain that approval, they were required to conduct clinical trials. So, why weren't the life-threatening side-effects noted during those trials?

Well, according to a synopsis of the study released by ASH (UK),
“Trial entry criteria included good health, male and female smokers aged 18 to 75, smoking at least 10 cigarettes per day during the past year, no prior use at all of varenicline or bupropion for any indication, and being motivated to stop smoking. Smokers were excluded if they had had serious or unstable disease within six months, weighed less than 7st 2lbs (100lbs / 45kg) or had a BMI of less than 15 or more than 38, had a history of drug or alcohol abuse in the past year, had used another form of tobacco, or marijuana, in the past month, had used NRT, clonidine or nortriptyline in the past month, had received any treatment for major depression in the previous 12 months, had a history of or current panic disorder, psychosis or bipolar disorder, or had contraindications for bupropion (Zyban and ellbutrin).”

In other words, the study participants did not accurately reflect the demographic for which the drug was intended. Only comparatively healthy individuals with a strong motivation to quit were included in the trials. The drug trials ignored the fact that a substantial portion of the smoking population for whom Chantix would be prescribed would likely suffer from the full spectrum of heath concerns which were deliberately excluded from the studies.

Even the authors acknowledge the limits of the trials.
“First, participants who volunteer for clinical trials of investigational drugs tend to be in better general health and are by definition more motivated than those in a typical primary care population. The external validity of the trial is also limited by the fact that individuals with serious medical illness or current or recent depression were excluded from the trial.”

The recent FDA ruling means that both the makers of Chantix and Zyban will be required to conduct clinical trials to assess the mental health risks associated with the drugs. Oh, well. Better late than never, as the old saying goes.

But, despite the alleged risks to users, Chantix (Champix) is still widely advertised on television and in other media. And, supporters of the drug in the anti-smoker cartel continue to aggressively promote the drug.

Dr. Curtis J. Rosebraugh, director of the drug evaluation office at the FDA which approved the drugs, is quoted as saying:
“Stopping smoking is a goal we should all be working towards. We don’t want to scare people off from trying a medication that could help them achieve this goal. You should just be careful.”

Just be careful? The logic (or lack of it) is mind-boggling. Smokers must be helped on their way to smoke-free Nirvana, even if it means killing off a few hundred and making life miserable for thousands more. But, what the Hell? Only smokers will suffer the alleged adverse consequences of using these drugs.

And, as Clive Bates, of ASH (UK), told BBC News Online: "Most of these people would have died anyway.” Uh-huh. Smokers, it seems, have become expendable; sacrificial lambs to be offered on the altar of the Great God, Public Health.

So what else is new?

1 comment:

humpty said...

Most smokers don't mind being 'expendable' if they could be one of the five chantix users who can actually kick the habit for good. So who's complaining ?