Chantix: How Does This New Quit Smoking Medicine Work?
1. Chantix binds to nicotine receptors and blocks them so that nicotine can no longer activate those receptors (an effect that pharmacologists sometimes call an “antagonist” effect). This means that when someone is trying to quit and they lapse and smoke a cigarette, they probably won’t get much satisfaction from smoking it, and will be less likely to smoke another.
2. When Chantix binds to nicotine receptors it also triggers some of the same effects that nicotine has (an effect pharmacologists call an “agonist” effect). This includes a small release of dopamine, the reward neurotransmitter in the brain. In this way Chantix dampens down nicotine withdrawal symptoms and cravings.
The results of clinical trials of Chantix have been very encouraging. In all the trials published to date, smokers treated with Chantix had a significantly higher quit rate than smokers treated with a placebo pill. (Note these were “double blind” trials in which no-one knew who got the real drug and who received the “dummy” pills until the end). In some of the trials Chantix was compared to bupropion (the drug marketed as Zyban for smoking cessation or Welbutrin for depression). In those trials more people quit with bupropion than placebo pills, but Chantix produced higher quit rates than bupropion. The other interesting finding has been that the longer people use Chantix the more likely they are to stay quit. The standard treatment consists of one week before the “Quit Date” (in which the dose is gradually increased while the person gets used to the drug) and then 12 weeks after the quit date at the full dose (two 1mg pills per day, one with breakfast and the other with dinner). But people who took it for an extra 12 weeks were less likely to relapse. Just this week a new trial was published. It reported that among smokers who took Chantix for a year, 37% remained smoke-free, compared with 8% among those receiving placebo pills.
Importantly, Chantix appears to have a good side-effect profile. Mild to moderate nausea is the most frequent symptom but it only infrequently leads to discontinuation. Sleep disturbance and abnormal dreams were the next most common side-effects but again these were typically mild.
Although this medicine appears to be very promising, it is important that people don’t expect a magic bullet that makes it easy to stop smoking. While Chantix appears to reduce cravings and withdrawal symptoms and to triple quit rates, people using it still have to put up with some continued urges to smoke. They should use all the usual helpful strategies (preparation, counseling, online support, get rid of tobacco etc) to quit smoking as well as the medicine.