It is being reported that the FDA has issued an early warning pertaining to an anti-smoking drug made by Pfizer called Chantix.

According to the agency, there may be an increased risk of suicidal thoughts in people taking the drug, and a recent death may also be linked to the drug which is also known as varenicline.

An early agency assessment "reveals that many of the cases reflect new-onset of depressed mood, suicidal ideation (thoughts) and changes in emotion and behavior within days to weeks" of starting treatment, the FDA said in a posting about the new review.

"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."

"My first thought is this is another example of the FDA being overly safety conscious in light of the withdrawal of certain products, such as Vioxx and Avandia," said Damien Conover, an analyst at investment research group Morningstar.

"When the (attention deficit disorder) drugs got associated with increased risk of suicidal thinking, you definitely saw a class effect of slower growth," he added.

Furthermore, the FDA stated that they are investigating reports of people becoming overly drowsy after taking the drug.

The FDA said it was "considering, but has not reached a conclusion about whether this information warrants any regulatory action."