Newly published research shows that Botox moves beyond its injection site and can weaken nearby muscles.
The study, conducted at the University of Calgary in Canada, adds to mounting evidence about unintended consequences of injections of Botox’s weakened version of botulinum toxin, at least in doses higher than those used to eliminate wrinkles.
Botox-maker Allergan of Irvine, meanwhile, notes that Botox has been used safely by millions of patients over the past two decades. Local doctors also report no problems.
Lead researcher Walter Herzog, co-director of Calgary University’s Human Performance Lab, told the Daily Mail newspaper in Britain, “What we found was that the toxin passed easily into the surrounding muscles and weakened all the muscles in the area. The results support other research that has already shown that botulinum can pass through muscle fascia (the packing tissue around muscles).”
“Our research showed that the toxin can also affect the working of the neighboring muscles,” he said.
In addition to its well-known uses as a wrinkle-fighter, Botox in stronger concentrations is used for an increasing number of muscle-related problems, including cerebral palsy, muscle rigidity after strokes, and muscle tightness that can cause incontinence or migraines.
“While I see the benefits of it as a therapeutic tool, its applications in humans are increasing and it is important we understand more about this product, which is a toxin,” Herzog said.
His study, which was published in the Journal of Biomechanics, involved Botox injections into cats.
Allergan spokesman Dr. Antony Fulford-Smith told the Daily Mail that evidence drawn from animal studies has limited application to humans.
“Dr. Herzog’s research was on cats and therefore it is inappropriate to make any conclusions at all about the safety of Botox in relation to humans,” he said. “It was a laboratory experiment using doses that would not normally be used in a therapeutic situation.”
“Botox has been used worldwide to treat millions of people for many conditions for nearly 20 years, providing huge relief in many cases. We closely monitor any adverse reactions and if used as indicated and injected in the right dose it is very rare for there to be any serious side-effects in relation to the spread of the toxin.”
Last month the Food and Drug Administration announced that 16 deaths occurred after patients were injected with Botox and a similar drug, Myobloc, which is not used as a cosmetic treatment. The FDA said it is reviewing safety warnings on those medications.
Only one of those deaths involved a patient who was injected with Allergan’s Botox Cosmetic. Her physician said the treatment did not cause the fatality, which occurred seven weeks afterwards.