Chantix Suicide Risk Questioned by New Study

The results of a new British study raise questions about whether side effects of Chantix, a stop smoking drug manufactured by Pfizer, increase the risk of suicides and suicide attempts. However, the researchers acknowledged that their study was limited, which could have affected the findings.

The study, which was published last week online by the British Medical Journal, analyzed a database of patients in the United Kingdom who tried to quit smoking using Chantix (varenicline) and other smoking cessation products.

Researchers from Britain’s Medicines and Healthcare Products Regulatory Agency and the University of Bristol looked at a database of more than 80,000 men and women between 18 and 95 years of age who used various anti-smoking treatments, such as Chantix, Zyban and nicotine replacement products. There were 10,973 Chantix users identified in the database, and researchers found no evidence of an increased risk for suicide, suicidal thoughts or depression with Chantix when compared to other smoking cessation products.

The findings contradict conclusions by the FDA, which ordered Pfizer to place a “black box” warning on Chantix this summer, alerting consumers that the drug had been linked to reports of psychological side effects, including suicide, depression, and hallucination. This is the strongest warning that can be placed on a prescription medication, and came after the FDA received reports of at least 90 suicides on Chantix and 188 suicide attempts.

Given the limitations of the British study, researchers cautioned that there could still be a two-fold risk of suicide with Chantix, or it may be halved. In addition, the researchers noted that suicidal thoughts were likely under-recorded in the medical databases, which raise further questions about the study. They indicate that additional research into the Chantix suicide risk is necessary.

Pfizer is currently conducting new clinical trials regarding the potential Chantix side effects, including individuals with psychiatric disorders, who were excluded from earlier studies before the drug was introduced.

Chantix was approved by FDA in 2006. It works by blocking the receptors in the brain that are commonly stimulated by nicotine, reducing the positive feelings that come from cigarettes. However, soon after Chantix was introduced, it became one of the drugs most associated with adverse event reports in the United States.

According to a report by the Institute for Safe Medication Practices, the FDA received 988 reports of serious problems involving the use of Chantix in the fourth quarter of 2007. The median average for 769 different drugs during the same quarter was only 5 reports of serious injuries per drug. Only 35 other drugs had more than 100 adverse event reports, and they included drugs like fentanyl, interferon beta, oxycodone, etanercept and other drugs used for serious illnesses, where the benefits are weighed against known risks that were typically contained in “black box” warnings.

Pfizer currently faces a growing number of Chantix lawsuits filed on behalf of users who have suffered serious or fatal injuries as a result of a suicide, suicide attempt or other unusual aggressive behavior while taking the drug. Last week, a panel of federal judges ordered that the federal Chantix litigation will be consolidated into an MDL and centralized in the Northern District of Alabama for pretrial litigation.