(Adds detail from drug label, paragraph 6)
By Susan Heavey
WASHINGTON, Oct 22 (Reuters) - Pfizer Inc’s (PFE.N) smoking-cessation drug Chantix should carry a strong warning about the potential risks of accidental injury and death, U.S. researchers said on Wednesday.
Pfizer defended its drug as safe and effective when used as directed. The drugmaker was aware of the reports of serious accidents, vision problems and heart trouble the researchers analyzed, but such reports were inconclusive, it said in a statement.
More than 1,000 health problems and injuries were reported in the first quarter of 2008 in patients taking the drug, including 50 deaths, researchers at the nonprofit Institute for Safe Medication Practices and Wake Forest University found.
The scientists analyzed post-marketing data submitted to the U.S. Food and Drug Administration about people who took the drug, which was approved in 2006.
Chantix, or varenicline, already carries a warning for depression, suicidal behavior, agitation and other unusual activity.
Its label also advises patients to use caution when driving or operating machinery until they know how the drug affects them. But the precaution stops short of warning patients not to engage in such activity.
The researchers first reported the rise of serious accidents, vision problems and heart trouble in patients taking the drug in May, citing 173 reports of accidents and injuries.
Immediately after the report, the U.S. Federal Aviation Administration banned use of Chantix by pilots.
In their latest findings, the researchers said there were 1,001 new reports of complications and deaths that included 15 traffic accidents and 52 incidents of blackouts or loss of consciousness.
The reports of problems with Chantix were greater than for any other prescription drug for the second quarter in a row, the researchers added.
The FDA is reviewing the reports to see if current information on the drug’s label is sufficient for doctors and patients, agency spokesman Christopher DiFrancesco said.
Under power granted to the agency last year, the FDA could order new warnings for the drug’s label, or just information on the reports. It could also choose not to act.
Pfizer, the world’s largest drugmaker, had been counting on Chantix to spur earnings as it prepares to face generic competition to its blockbuster cholesterol drug Lipitor and other products.
U.S. sales of the smoking drug dropped by more than a third in the third quarter to $109 million. Sales of Chantix overseas, where it is sold as Champix, grew 3 percent to $207 million.
Pfizer resurrected television commercials for Chantix last month after withdrawing them in January, according to media reports. Company spokeswoman Kristen Neese said the ads “will continue because there are few things that provide greater health benefits than quitting smoking.”
Shares of Pfizer fell nearly 3.5 percent to close at $16.74 on the New York Stock Exchange. (Additional reporting by Lisa Richwine; editing by Tim Dobbyn, Leslie Gevirtz, Gary Hill)