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FDA Warns of Side Effects, Death from Botox Use
Severe side effects -- including respiratory distress and death
-- have been linked to the use of Botox or a related drug, especially among
young users who suffer from cerebral palsy.
In a Feb. 8 “early communication” notice, the federal Food and
Drug Administration said it would review the safety of Botox and Botox Cosmetic
(Botulinum toxin Type A) and Myobloc (Botulinum toxin Type B). The agency has
not yet decided whether to take regulatory action.
The FDA investigation is likely to focus on side effects
stemming from the drugs’ “off-label” use in treating cerebral palsy patients.
The most serious cases involved symptoms that resembled botulism, a rare, but
serious paralytic illness caused by the toxin botulin.
Botox and Myobloc have therapeutic uses in reducing body
spasms, while Botox Cosmetic is widely used to temporarily reduce facial
wrinkles.
The drugs have long carried warnings about several severe side
effects. But the agency said there was now evidence of “potentially
life-threatening systemic toxicity” from the medication’s use when it spreads
from the injection site to distant parts of the body.
The biggest risk appears to be for children, where there have
been reports of hospitalization and death. But weakness and numbness in the
lower extremities have also been reported among adult users, some of whom
required hospitalization.
The FDA announced the review shortly after Public Citizen, a
public interest watchdog group, urged the regulatory body to beef up mandatory
warnings for the drugs.
“In some cases, the toxin has spread to other parts of the
body with serious consequences, such as paralysis of respiratory muscles and
difficulty swallowing (dysphagia), the latter possibly leading to food or
liquids entering the respiratory tract and lungs, causing aspiration pneumonia,”
a Public Citizen press release stated.
According to the Public Citizen’s analysis of FDA data, makers
of the drug have reported 180 U.S. cases where patients developed sometimes
life-threatening conditions after receiving injections, including 16 deaths. The
FDA information comes from voluntary reports, which have been estimated to
account for only 10 percent of actual cases, the press release stated.
FDA officials declined to disclose the number deaths or
reports of serious side effects, except to say there were a “relative handful”
and fewer than 100.
Botox and Myobloc work by blocking impulses to muscles, causing them to relax.
Myobloc is approved for treating severe neck spasms. Botox has two approved
uses.
* Therapeutic. Botox is used to control spasms of the
eyelids, severe neck muscle spasms, and excessive sweating;
* Cosmetic. Botox Cosmetic is used to reduce unsightly
“frown lines” between the eyebrows. The injectable drug smoothes those wrinkles
by paralyzing nerve endings. A single treatment can last up to six months.
Allergan, Inc., the maker of Botox, reported $1.21 billion in
sales last year, split equally between therapeutic and cosmetic uses.
Botulinum toxins have been put to “off-label” use in treating
limb spasticity (severe arm and leg muscle spasms) in children and adults with
cerebral palsy. The FDA has not established any safe use or dosage of botulinum
toxins for that purpose.
However, Allergan said the drug has won approval for treating
cerebral palsy in children in about 60 countries. It’s typically used in higher
doses for that treatment than for its cosmetic use in smoothing wrinkles.
“The pediatric botulism cases occurred in patients less than
16 years old, with reported symptoms ranging from dysphagia to respiratory
insufficiency requiring gastric feeding tubes and ventilatory support,” the FDA
said. “Serious outcomes included hospitalization and death.”
In reports of botulism among adults, patients experienced
difficulty holding up their heads, difficulty swallowing, and drooping eyelids.
Those side effects could be related to approved therapeutic uses. Current
labeling on Botox, Botox Cosmetic and Myobloc already warns of those adverse
reactions near the injection sites.
However, in some adult cases, “reports described systemic
effects that occurred distant from the site of injection and included weakness
and numbness of the lower extremities,” the FDA said. It’s unclear from the FDA
notice whether those side effects stemmed from the drugs’ use in treating adults
with cerebral palsy.
Among the adult cases that were serious, including those
involving hospitalization, none required feeding tubes or breathing support, the
FDA said, and no deaths were reported.
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