Chantix, once hailed as a huge success for drug maker Pfizer Inc., is quickly losing its luster. Already linked to suicidal thoughts and behavior, a new report last week said Chantix could be associated with heart problems and other serious side effects. Chantix was Pfizer’s most promising drug, with some analysts estimating its sales could reach $2.28 billion by 2012. But Chantix’s problems could soon have many rethinking those forecasts.
Chantix, approved in the US in 2006, works by blocking nicotine receptors to the brain. Chantix is the first such nicotine receptor partial agonist approved by the Food & Drug Administration (FDA). It was heralded as an alternative to other smoking cessation drugs and nicotine replacement therapy.
In the US, 34 Chantix users have reportedly committed suicide. According to an FDA Nov. 20 Early Communication, the agency said that its preliminary assessment revealed that many of the cases reflected new-onset of depressed mood, suicidal ideation, and changes in emotion and behavior within days to weeks of initiating Chantix treatment. In February, the FDA said “it appears increasingly likely that there may be an association between Chantix and serious neuropsychiatric symptoms.” The agency said that it had asked Pfizer to elevate the prominence of safety information regarding suicidal thoughts and other psychiatric problems to the warnings and precautions section of the Chantix prescribing information, or labeling.
Last Tuesday, the Institute for Safe Medication Practices issued a report detailing Chantix adverse event repots to the FDA. The report specifically cited 224 reports of potential heart-rhythm disturbances, 372 reports of possible movement disorders and 544 reports of likely glycemic problems, including diabetes. There were also reports of traffic accidents and falls linked to Chantix. The Institute’s report has already gotten the attention of the Federal Aviation Administration, which has banned its use by pilots and air traffic controllers.
None of this is good news for Pfizer. It is expected that many analysts will revise their once-rosy Chantix sales forecasts soon. Some analysts have already said forecasts for Chantix sales could be downgraded by as much as 30 percent. Unfortunately for Pfizer, Chantix is the company’s second biggest growth driver, after Lyrica, a drug for fibromyalgia.