NEW YORK (FORTUNE) -
A case wending its way through the courts could put antidepressants like Prozac and Zoloft under an even bigger cloud -- and cost their makers even more money.
Two years ago, Tim "Woody" Witczak killed himself at age 37 soon after going on Pfizer's Zoloft -- the top-selling member of Prozac's class of drugs, known as selective serotonin reuptake inhibitors, or SSRIs. His wife says Witczak was an upbeat man who was prescribed Zoloft for job stress.
"Woody's death was the most out-of-the-blue, out-of-character death," Kimberley Witczak says. She has sued Pfizer, alleging that Zoloft induced the suicide, and that the company failed to warn about the drug's potential to cause perilous side effects.
Pfizer (Research) declined to comment on the suit, but a spokesman asserted that there is "no scientifically based" evidence suggesting Zoloft can induce suicidal acts.
The Witczak case, which may play out in court next spring, is only the latest battle in a long, bitter dispute about SSRI side effects. Last year, SSRIs and older antidepressants were shown to double the risk of suicidal thoughts and behavior in children and adolescents. That discovery prompted the FDA to slap a stern "black box" warning on the drugs' package inserts. Now, a similar warning concerning adults appears probable, say experts.
The risk that prompted the black-box warning last year is limited, and many psychiatrists feel that it has been exaggerated. But the cloud of doubt over the drugs could have huge repercussions, vaporizing billions of dollars of future sales, increasing pressure on policymakers to curtail direct-to-consumer drug ads and prompting lawsuits.
SSRIs have been one of Big Pharma's greatest successes. Perhaps one in 20 adult Americans take them. Last year SSRIs and similar antidepressants called SNRIs racked up sales of nearly $11 billion, according to IMS Health. Besides Eli Lilly's (Research) Prozac, brands like Zoloft, GlaxoSmithKline's Paxil, Forest Laboratories (Research)' Celexa, and Solvay Pharmaceuticals' Luvox are now household names.
Events leading up to last year's black-box warning, however, suggest signs of their risks were downplayed or ignored. In June 2004, for example, New York Attorney General Eliot Spitzer sued GlaxoSmithKline (Research), alleging that it had fraudulently withheld unfavorable data on youngsters treated with Paxil. Glaxo, which asserts the lawsuit was "unfounded," settled by agreeing to post its clinical results on the web.
Critics also assert that the drugs have been overprescribed for relatively minor maladies. In April, the British House of Commons Health Committee issued a report concluding that industry promotions have "worked to persuade too many professionals that they can prescribe [SSRIs] with impunity" to treat "unhappiness [that] is part of the spectrum of human experience, not a medical condition."
The commotion about suicide risks began in 1990, when Harvard researchers reported that six depressed patients had developed "intense, violent suicidal preoccupation" on Prozac. The following year, an FDA advisory panel concluded that there was "no credible evidence" Prozac promotes suicidal or violent impulses.
But a less reassuring analysis had unfolded behind the scenes. In 1990, an FDA safety official wrote an internal memo to his superiors sharply criticizing a report that Eli Lilly had submitted to the agency in hopes of quelling the suicide concerns.
Another controversy, this one about withdrawal symptoms, erupted in the mid-1990s. Now some 3,000 suits alleging Paxil caused such symptoms have been filed against Glaxo, says Karen Barth Menzies, an attorney at Baum Hedlund, a Los Angeles law firm representing plaintiffs in such suits. Glaxo's drug washes out of the body more quickly than most other SSRIs, hence is more prone to cause withdrawal symptoms. Glaxo concedes that "discontinuation" symptoms may occur when people quit taking Paxil, but says they are mostly "mild" to "moderate." The company denies allegations that Paxil is addictive, or that it has tried to hide data on side effects.
How the controversy will affect industry revenues and profits over time isn't clear -- concerns about SSRIs may help speed the transition to newer, pricier antidepressants, offsetting the fiscal fallout. But more SSRI flare-ups clearly loom ahead.
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