While thousands if not millions of people report no adverse affects from the use of botulinum neurotoxin to smooth muscles, a new report suggests you might be harming your brain.
The study is published in the Journal of Neuroscience by researchers at the University of Padova in Italy.
Researchers injected the botulinum neurotoxin type A near the rats’ whiskers. The toxin actually moved to the brain stem, appears to disrupt nerve cells' ability to communicate and may change spinal cord circuitry, the authors wrote.
Those changes continued to be observed up to six months after the injection.
Researchers were surprised and say that the study indicates that the human experience should be examined more closely for any changes to the central nervous system.
Botox Cosmetic® is made from the type A botulinum toxin by Allergan.
With more than $1.2 billion in sales last year, Allergan says millions have used this treatment. Dr. Matthew Avram of Massachusetts General Hospital’s Dermatology, Laser and Cosmetic Center in Boston told Bloomberg.com in an interview that, “we’re not seeing major central nervous system uses with it.”
Dr. Avram was not involved in the study but he warned, ``The idea that there could be some transmission of this to the central nervous system needs to be followed up.”
A spokeswoman from Allergan, Caroline Van Hove says that more work is necessary because the study contradicts previous findings and it lacks a conclusion.
In a statement, Van Hove said, “The authors used a laboratory preparation of botulinum toxin and did not use Botox®, and data suggest that different preparations of botulinum toxin react differently in both the laboratory and in clinical practice.”
But these findings are not entirely new.
Myobloc®, a competing form of botox uses type B neurotoxin and chief medical officer for maker Solstice Neurosciences, Edgar Salazar-Grueso says that in monkeys studies show toxin A migrates more than type B. And, he says, monkeys are more like humans than rats or mice.
And the FDA is reviewing adverse reaction reports including respiratory reaction and death following the use of botulinum toxins types A and B. The reports suggest that the botulinum toxin spreads in the body beyond the injection sites.
The warning label for both Myobloc® and Botox® already includes literature about the possibilities of breathing difficulties and swallowing problems. The most serious cases have occurred in children with cerebral palsy who received high doses of botulinum toxin to treat limb spasticity, an off-label use.
In January, Public Citizen asked for black-box label warnings after 16 deaths were linked to the use of the toxin. #