An extremely potent poison, originally developed as a nerve gas before the Second
World War. Its therapeutic use is now recognised in a range of symptoms. Botulinum
toxin is a drug that may be used to treat spasticity and spasms. Researchers are
also looking into the drug as a treatment for bladder problems.
How botulinum toxin works
By preventing nerve messages being transmitted to muscles, thus causing paralysis.
In small, therapeutic doses, botulinum toxin is injected into individual muscles
to prevent the nerve messages that cause spasticity and spasm.
The effects of an injection with botulinum toxin can last from six to ten months.
Side effects may occur such as:Early Communication about an Ongoing Safety Review
about Botox and Botox Cosmetic - Botulinum toxin Type A, and Myobloc - Botulinum
toxin Type B.
This information reflects FDA’s current analysis of available data concerning these
drugs. Posting this information does not mean that the FDA has concluded there is
a causal relationship between the drug products and the emerging safety issue. Nor
does it mean that FDA is advising healthcare professionals to discontinue prescribing
these products.
FDA is considering, but has not reached a conclusion about whether this information
warrants any regulatory action. FDA intends to update this document when additional
information or analyses become available.
FDA has received reports of systemic Serious reactions including respiratory compromise
and death following the use of botulinum toxins types A and B for both FDA-approved
and unapproved uses. The reactions reported are suggestive of botulism, which occurs
when botulinum toxin spreads in the body beyond the site where it was injected.
The most serious cases had outcomes that included hospitalisation and death, and
occurred mostly in children treated for cerebral palsy-associated limb spasticity.
Use of botulinum toxins for treatment of limb spasticity (severe arm and leg muscle
spasms) in children or adults is not an approved use in the U.S.
These serious systemic serious reactions occurred following treatment of a variety
of conditions using a wide range of botulinum toxin doses. FDA is currently reviewing
safety data from clinical studies submitted by the manufacturers of Botox, Botox
Cosmetic and Myobloc, as well as post-marketing serious event reports and the medical
literature.
Approved for treatment of conditions such as blepharospasm (spasm of the eyelids),
cervical dystonia (severe neck muscle spasms), and severe primary axillary hyperhydrosis
(excess sweating). Botox Cosmetic, also botulinum toxin Type A, is approved for temporary
improvement in the appearance of moderate to severe facial frown lines.
Myobloc - botulinum toxin Type B
Approved for the treatment of adults with cervical dystonia; the safety and effectiveness
of Myobloc for cervical dystonia in children have not been established.
FDA is aware of the body of literature describing the use of botulinum toxins to
treat limb spasticity in children and adults. The safety, efficacy and dosage of
botulinum toxins have not been established for the treatment of limb spasticity of
cerebral palsy or for use in any condition in children less than 12 years of age.
The current prescribing information (labelling) for Botox, Botox Cosmetic and Myobloc
describes Serious reactions occurring in regions near the site of injection for each
product’s approved uses, such as dysphagia - difficulty swallowing after injections
to treat cervical dystonia, or ptosis - drooping eye lids after injections for glabellar
frown lines or for strabismus and blepharospasm.
The Warnings sections of the labelling for both botulinum toxin products note that
important systemic Serious effects, including severe difficulty swallowing and difficulty
breathing have occurred in people with neuromuscular disorders after local injection
of typical doses of botulinum toxin.
FDA now has evidence that similar, potentially life-threatening systemic toxicity
from the use of botulinum toxin products can also result after local injection in
people with other underlying conditions such as those with cerebral palsy associated
limb spasticity. Systemic toxicity has been reported in children, several of whom
required feeding tubes and/or ventilation (breathing) support.
Until such time that FDA has completed its review, healthcare professionals who use
medicinal botulinum toxins must:
Understand that potency determinations expressed in “Units” or “U” are different
among the botulinum toxin products; clinical doses expressed in units are not comparable
from one botulinum product to the next
Be alert to the potential for systemic effects following administration of botulinum
toxins such as: dysphagia, dysphonia, weakness, dyspnea or respiratory distress
Understand that these effects have been reported as early as one day and as late
as several weeks after treatment
Provide people and caregivers with the information they need to be able to identify
the signs and symptoms of systemic effects after receiving an injection of a botulinum
toxin
Tell people they should receive immediate medical attention if they have worsening
or unexpected difficulty swallowing or talking, trouble breathing, or muscle weakness
