Pfizer Halts Distribution of Smoking Cessation Drug, Chantix

Pfizer recently paused distribution of its smoking cessation treatment, Chantix, after finding nitrosamines in the pills.

Nitrosamines are cancer-causing agents. Previously, Pfizer had contacted other companies whose drugs had N nitrosodimethylamine (NDMA) over accepted levels. 

"The benefits of Chantix outweigh the very low potential risks, if any, posed by nitrosamine exposure from varenicline on top of other common sources over a lifetime," Pfizer spokesperson Steven Danehy said in an email to Reuters.

Chantix is specifically designed to partially activate the nicotinic receptor. The drug works to block the pleasurable effects of smoking and reduces the craving and withdrawal symptoms from quitting. 

FDA approved Chantix in 2006. This was the first drug approved for smoking cessation in over a decade. 

The agency based its approval based on trials that enrolled 2,000 cigarette smokers who smoked 21 cigarettes per day for an average of nearly 25 years. 

In two studies, patients receiving a 12-week course of Chantix therapy 1 milligram twice daily were more likely to quit than those taking a placebo. These patients were also more likely to quit than patients taking bupropion 150 milligrams twice daily after 12 weeks. 

In a statement, Hank Mckinnel, former CEO of Pfizer, stated that smoking causes one in five deaths in the US and costs the US healthcare system nearly $167 billion annually.

With the approval, patients now had access to a groundbreaking treatment option. 

But in 2014, many patients who were prescribed Chantix to stop smoking blamed the drug for triggering suicidal thoughts, behavioral changes, hostility, agitation, depression, and other psychological problems. 

Pfizer spent $300 million to settle the lawsuits and the court ruled that the nationwide litigation should be dismissed.

Just one year later, FDA updated its warning label for Chantix to include information about various studies investigating the risk of neuropsychiatric side effects on mood, behavior, or thinking when taking Chantix. 

The studies included observational studies and analyses that Pfizer conducted of randomized controlled clinical trial data.

Global revenue from Chantix fell 17 percent to $919 million in 2020 as COVID-19 hampered demand and Pfizer lost patent protection in the US last November. 

The recent pause in distribution is out of an “abundance of caution” and pending further testing.