On December 16, the FDA permitted drugmaker Pfizer Inc. to remove the black box warning from the label of its smoking-cessation drug, Chantix. The agency required the stringent warning in 2009 after receiving thousands of reports linking the drug to suicidal thoughts, hostility, agitation, and other mental health issues. 
Seven months ago, European health regulators lifted a similar warning on the drug, called Champix in Europe.
Pfizer failed to convince the FDA to remove the black box warning in 2014 after the agency decided to wait for more trial data. The company has spent opulently on advertising and settling Chantix-related lawsuits.
Since then, Pfizer has released data that showed Chantix did not significantly increase the side effects. The trial involved 8,000 smokers who had no prior history of psychiatric problems. 
It’s important to note – while not defending Chantix – that quitting smoking in any fashion can cause major withdrawal symptoms, including irritability, mood swings, and depression. Additionally, psychiatric conditions are more common in smokers than in non-smokers.
In September, an independent panel to the FDA voted in favor of removing the warning by a slim margin and said the benefits of Chantix outweighed its side effects and that there was no clear evidence of causality between the drug and the side effects. 
But FDA scientists weren’t completely satisfied with the panel’s assessment and flagged numerous inconsistencies in data collection. After removing the inconsistent data, the trial results appeared to coincide with Pfizer’s conclusion.
Though Pfizer was allowed to remove the black box warning, the FDA said the Chantix label should contain the post-marketing reports of the serious side effects linked to the drug.
Additionally, the FDA required that the Chantix label mention that the drug was more effective than other available smoking-cessation therapies.
Pfizer Chief Medical Officer Dr. Freda Lewis-Hall said:
“Especially in patients with mental illnesses, there’s been a kind of a barrier in the shape of a box and in the shape of a bias … so the boxed warning, based on the post-marketing report we felt needed to be clarified.”
In an online post, the FDA said:
“The risk of these mental health side effects is still present, especially in those currently being treated for mental illnesses such as depression, anxiety disorders, or schizophrenia, or who have been treated for mental illnesses in the past.” 
Thousands of lawsuits have been filed over Chantix on behalf of users who allege the drug made them depressed, angry and, most often, suicidal.
The most famous case occurred in September 2007, when Texas musician Carter Albrecht, best known for his work with Edie Brickell & The New Bohemians, was shot to death in Dallas by a neighbor who said Albrecht showed up at his back door around midnight in a drunken rage after storming out of his girlfriend’s home. When the neighbor’s husband fired a warning shot at Albrecht, thinking he was a robber, it hit him in the head and killed him. 
Albrecht had been taking Chantix to quit smoking in an effort to save his singing voice. He began experiencing personality changes and vivid dreams almost immediately, according to his girlfriend.
In another horrifying case, a jail inmate sued Pfizer claiming Chantix made him gouge his eyes out while behind bars in 2014. Michael Shabsis began taking Chantix in 2013 to quit smoking.
Four months later, he suffered a psychotic episode that caused him to violently attack his grandfather. He was put in isolation in jail, despite being in the midst of a severe manic episode. In the lawsuit, Shabsis claimed that the pain became so intense and the glare of the lights became so disturbing that he used “his own hands and fingers to gouge out both eyes as he believed he was in hell.”
 Associated Press
 ABC News
Featured image source: Photographer: JB Reed/Bloomberg News