The institute called for a stronger risk warning on the Chantix label.
A Pfizer statement released Wednesday speculated that the large number of reports might be linked to the high level of adverse publicity associated with the drug. It noted also that nicotine withdrawal could cause irritability, depressed mood and other changes in behavior.
"Based on the [the] totality of data, we stand by the efficacy and safety profile of Chantix when used as directed," the statement said. "Chantix labeling accurately reflects its efficacy and safety event reports and clinical trial data."
Figures released Tuesday by Pfizer showed U.S. sales of Chantix at $96 million in the third quarter, down 49% from the same period last year.
The increase in deaths during the first quarter was not dominated by any one drug. Instead, 10 drugs each caused more than 100 deaths, compared with an average of one to three drugs in previous quarters.
Many of the reports were linked to powerful painkillers or narcotics such as oxycodone, fentanyl, morphine, methadone and hydrocodone, all of which have a high potential for abuse.
Acetaminophen and ibuprofen were among the top 10 drugs causing both injuries and deaths. The drugs are often used in suicide attempts because they are easily accessible. Overdosing or prolonged usage of either of the over-the-counter medications can cause side effects including gastrointestinal damage and heart attacks.
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thomas.maugh@latimes.com
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(BEGIN TEXT OF INFOBOX)
Drugs with the most complaints
Medications that accounted for the largest number of adverse events during the first quarter of 2008:
SERIOUS INJURY
1. Varenicline (smoking cessation) 1,001 cases
2. Heparin (blood thinner) 779
3. Fentanyl (painkiller) 631
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DEATHS
1. Oxycodone (painkiller) 185 cases
2. Alprazolam (anti-anxiety) 163
3. Acetaminophen (painkiller) 160
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Source: Food and Drug Administration
