Behavioral problems linked with Chantix User

Thinking of quitting smoking? Beware of using Chantix. Food and Drug Administration has received reports mentioning that Pfizer Inc.'s (PFE) new smoking-cessation drug Chantix induces many behavioral changes in a person. The most common of these side effects are suicidal thoughts, aggressive and violent behavior and erratic mood swings.

FDA is still in the process of gathering information but has advised the physicians to properly monitor the behavior of the patients who are using this drug. Meanwhile Pfizer has added the warnings in the product label mentioning the reports of depressed mood, agitation, changes in behavior, suicidal ideation, and suicide in patients attempting to quit smoking while taking Chantix.

Pfizer is the world leader in medicine in terms of sales. After this information hit the markets, the increasing Pfizer shares fell to an annual low of $22.42 on Tuesday afternoon, and closed at $22.72. The stock fell 37 cents to $22.35 in premarket electronic trading. Chantix has already generated about $600m (£290m) in sales this year, with $241m coming only in the third quarter.

Chantix is a nicotine-free, oral tablet which is to be taken twice a day for 12 weeks to help adults quit smoking. This works by cutting the pleasure of smoking and reducing withdrawal symptoms by the help of an active ingredient Varenicline.

The investigations are being carried out to find the reason of a Texas musician’s death, who died while he was on a prescription of this drug. The company however said that there is still no scientific reason for us to believe that the death has been caused due to the drug. The company released a data saying that there were no such cases of suicides when the trials were carried out on 5000 people.

The drug won regulatory approval last year to aid adults trying to quit smoking and sales totaled $101 million.

The FDA said on its Web site: "The role of Chantix in these cases is not clear because smoking cessation, with or without treatment, is associated with nicotine withdrawal symptoms and has also been associated with the exacerbation of underlying psychiatric illness. However, not all patients described in these cases had pre-existing psychiatric illness and not all had discontinued smoking."

Goldman Sachs analyst James Kelly believes that the news will probably have a bad effect on Pfizer’s stocks. Kelly thinks that Chantix is an important growth driver for Pfizer's sales growth, as the drug is effective and more and more people are using this drug to quit smoking.

"The efficacy has been superior to other smoking cessation products on the market, allowing the drug to enjoy better uptake than most smoking cessation products," he said in a note to clients.

"New prescriptions have risen 13 percent sequentially this quarter on a quarter-to-date basis, an acceleration from the prior quarter," he added.