Dangers of Paxil Withdrawal
Quit Paxil, And Then: Zap!
Complaints Surface About Stopping Drug
By Brian Reid
Special to The Washington Post
Tuesday, August 27, 2002; Page HE01
Paxil, the world's best-selling antidepressant, has become the target of growing
complaints that stopping the drug causes severe side effects ranging from
flu-like symptoms to electric-shock-like sensations in the brain that patients
have labeled the "zaps." This marks the first time that one of the new
generation of antidepressant medications, often described as non-habit-forming,
has been accused of being addictive. The patient complaints, which previously
circulated chiefly on electronic bulletin boards and specialized Web sites,
became more public last week when a federal judge in California ordered the
drug's maker, GlaxoSmithKline, to pull TV ads that boast the drug is "not
habit-forming." The judge later put that ruling, which said the ads may have
underplayed the drug's possible role in causing withdrawal symptoms, on hold.
Both Glaxo and the Food and Drug Administration (FDA) have challenged the
decision, part of a California court case brought on behalf of Paxil users.
At stake, potentially, is the treatment of thousands of U.S. patients on Paxil,
which brought Glaxo almost $3 billion in revenue last year and was prescribed
more than 70 million times in the last decade. That growth has been driven in
part by an expanding list of uses. Paxil is approved for the treatment of
depression, obsessive-compulsive disorder, panic disorder, social anxiety
disorder, post-traumatic stress disorder and generalized anxiety disorder.The
judge's initial action highlights concerns that have dogged the drug since it
was introduced a decade ago. Although Paxil has become a staple of pharmacologic
treatment for depression and anxiety, the very chemical attributes that make it
a wonder drug for some patients may also contribute to symptoms when the drug is
stopped.
A member of a class of drugs known as selective serotonin reuptake inhibitors
(or SSRIs), which includes Prozac and Zoloft, Paxil works by ensuring that the
chemical serotonin, which the brain sends from one nerve cell to another,
reaches its destination. (In depressed individuals, serotonin is often
reabsorbed by sender cells before it can be transmitted.) Over the course of
treatment, brain cells adapt to the presence of the drug, changing their
physical properties.
Paxil, however, breaks down more quickly than Prozac and Zoloft. Once Paxil is
stopped, the levels of the drug in the cells drops quickly, say medical experts,
triggering the kinds of problems that prompted the lawsuit against Glaxo. One
patient involved in the California suit, Pamela Fikter, described the sensation
as "like I was going crazy," according to court documents. "I was dizzy,
light-headed, uncoordinated. . . . I was so terrified that something very
serious must be wrong with me."
Reports of similar ailments in patients who had stopped taking Paxil began
showing up in the medical literature within a few years of the drug's 1992 U.S.
debut.
By the late 1990s, clinical studies offered evidence that the symptoms
associated with discontinuing use of the drug -- ranging from flu-like ailments
and nausea to dizziness, insomnia and electric-shock-like sensations in the
brain -- appeared more often in patients treated with Paxil than in patients
treated with other psychotropic drugs. That has spawned a network of Web sites
and bulletin boards, with names like www.quitpaxil.org, devoted to spreading
information on the side effects. And it prompted Baum, Hedlund, Aristei Guilford
& Schiavo, a California law firm that had represented antidepressant users in
past suits, to launch legal action last summer claiming that Paxil patients had
been misled and asking for punitive damages against Glaxo, the world's
second-biggest drug maker.
The evidence from the medical research and the side effect reports submitted to
the FDA have convinced experts on both sides of the issue that some patients who
stop taking the drug -- especially those who halt it abruptly -- will experience
symptoms as the drug washes out of their system.
The 'Withdrawal' Question
But causality is hotly debated. Last December, Glaxo changed Paxil's label,
under FDA direction, to include reports of symptoms following discontinuation of
the drug. The change reads pointedly that the symptoms "may have no causal
relationship to the drug." It also never mentions the word "withdrawal."
Still, the change gave doctors FDA-sanctioned instructions to be on alert for
the problem, encouraging physicians to recommend "a gradual reduction in the
dose rather than abrupt cessation."
Where disgruntled Paxil patients and Glaxo have parted ways is not on whether
the symptoms exist but rather whether the symptoms are the mark of a
habit-forming drug or just a mild, expected consequence of treatment. The
patients in the lawsuit refer to the side effects as "withdrawal symptoms" that
can make stopping the drug disabling. The drug maker refers to the same effects
as "discontinuation" symptoms.
A final ruling in favor of the plaintiffs, who are seeking reimbursement for
their Paxil prescriptions and for medical treatment in addition to punitive
damages, could harm both Glaxo's bottom line and the drug's image.
"Clearly, we disagree with the ruling and we don't believe that the ads were
misleading," said Alan Metz, Glaxo's vice president for clinical development.
"There is no evidence that Paxil is addictive." The FDA backed the company's
position, arguing in a court filing that "FDA scientists that have considered
this very issue do not regard [Paxil] to be habit-forming."
Distinguishing between a drug that is addictive and one that has side effects
associated with going off it is the key to Glaxo's contention that the drug
isn't habit-forming.
The company and the FDA note that other non-addictive drugs, such as steroid
treatments and some high-blood-pressure medications called beta blockers, also
leave patients at risk of problems when they stop taking the medications. But
the FDA says neither those drugs nor Paxil prompts the kind of "drug seeking"
behavior associated with addictive drugs like opium or cocaine.
"Patients ask me, 'Is this habit-forming?' I say no," said Fred Goodwin, a
professor of psychiatry at George Washington University Medical School and the
former head of the mental health branch of the National Institutes of Health.
"But if you stop it suddenly, your body isn't going to like it very much."
But other doctors and patients say Glaxo shouldn't dismiss ill effects as
common, expected events, even if Paxil users don't act like cocaine addicts.
"The way they phrase it, you would think that most of the withdrawal is mild,"
said Joseph Glenmullen, the Harvard psychiatrist who wrote "Prozac Backlash."
"Clearly, this is withdrawal and that's what it should be called. . . . It's
like throwing a car that's going 60 miles an hour into reverse. The cells were
making adaptation to living with the drug 24 hours a day."
Brian Reid is a regular contributor to the Health section.
© 2002 The Washington Post Company
Last Updated on
02/20/05
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