Wednesday, 13 April 2011

Nicotine receptors in the brain: Of Champix and vaccines

As the scale of the radiation disaster in Japan becomes clear we learn that a nicotine vaccine is on the way. Just what the doctor ordered.

Comparisons with Champix should raise alarm bells (see link from Dick Puddlecote's post). Champix works by attaching itself to and blocking nicotine receptors in the brain. As a side effect, it can also block serotonin receptors in the brain, as described here by lawyers involved in Champix litigation. Champix has been banned for use by pilots for many years now. The risk of adverse consequences is very well known.

Much as I distrust antis, I can't go along with the idea that they have produced a drug that would block smokers from experiencing any pleasure at all. Even although some people find it hard to believe it, parts of the brain do respond to nicotine specifically, and it is these receptors that the manufacturers of Champix have attempted to block.

Smokers are, however, expected to accept a fair risk that they will react badly to Champix. And that doesn't just mean a sore head. If you're unlucky, the Champix blocks your seratonin receptors too:
Varenicline, the active ingredient of Chantix, has only one significant side effect: it also has an affinity for the 5-HT3 serotonin receptor. If the varenicline binds to this serotonin receptor, the serotonin response, like the nicotine response, is inhibited. Serotonin regulates several stress hormones, so an inhibition of serotonin reception can lead to side effects like nausea, headaches, anxiety disorders, and changes in libido and appetite, similar to side effects seen for SSRI antidepressants.
There is no shortage of warnings and stories on the internet on this drug.

ASH Scotland, perhaps uniquely, tells us 'there is emerging evidence that varenicline is safe and effective for people with mental health problems'. Not by my definition of the word 'safe', there isn't.


Anonymous said...

Chantix reduces dopamine as well as serotonin.

The reduction of both of these chemicals causes severe physchological symptoms with severe depression being the most common.

The treatment for severe depression is Prozac.

What a coup for the pharmaceutical companies.

Anonymous said...

Prozac is a serotonin re-uptake inhibitor. It just ensures that there is serotonin available to bind to receptors. If the receptors are blocked the amount of serotonin available is irrelevant. Prozac would not only not help, but might well make things worse by creating high local concentrations of serotonin that desensitize the remaining available receptors.

Anonymous said...

I took champix twice. During the first semester and last semester of my 5 semester program. Although the symptoms are not noticeable, the fact that my grades where 80 when I was on it and 70 when I was off it shows that it did something. I also noticed a better social life, higher self confidence and self esteem. It really does wonders for me. So I never stopped taking it, it's been 11 months. It helped stop me from thinking so much.