Last week, the Food and Drug Administration released a list of about 20 pharmaceutical drugs that the agency’s researchers are closely monitoring for potential safety concerns. Not surprisingly, Chantix (Varenicline) claimed a spot on the list. According to the FDA, the drug is being watched to determine whether it causes or contributes to angiodema (rapid and potentially life-threatening swelling of skin and tissue), other serious skin reactions, visual impairment, and accidental injury.
Data pulled from the FDA’s Adverse Event Reporting System (AERS) between October and December of 2008 suggested that Chantix may be linked to the side effects. The FDA will continue to monitor Chantix for an unspecified length of time until it determines what, if any, regulatory action is needed.
The FDA does not fully test prescription drugs for safety before allowing them to enter into the market. Why? It’s a matter of logistics more than anything. Typically, FDA studies are designed to measure a drug’s effectiveness using thousands of patients who willingly participate in pre-market clinical trials. These patients obviously represent a very small slice of U.S. population. The FDA also relies on studies conducted by the pharmaceutical companies themselves to determine how effective test drugs are. If new drugs that have passed tests for efficacy appear to be reasonably safe, then FDA researchers give them the green light.
The FDA, incidentally, reviewed Chantix in six months rather than the regular review time of 10 months.
The millions of people in the U.S. and around the world who started taking Chantix when it debuted on the world market in May 2006 became patients in the world’s first mass clinical trial. Most people assume that the FDA seal of approval means that the drug will be perfectly safe, but the truth is that most of a drug’s risks are not known until it is prescribed to millions of consumers.
The first reports of adverse events linked to Chantix emerged just months after the drug was released to the public. On February 1, 2008, the FDA issued a statement saying “it appears increasingly likely that there is an association between Chantix and serious neuropsychiatric symptoms.”
By May 2008, Chantix was linked to more than 3,000 reports of serious side effects. By November of the same year, data from the FDA’s Adverse Event Reporting System showed that more reported serious injuries resulted from Chantix than any other prescription drug.