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Botulinum Toxin Safety Warnings; Established Names of Drugs Changed

On August 3, 2009 the U.S. Food and Drug Administration announced an update on a previous safety alert on four botulinum toxin drug products. The update notes that all four drugs now contain boxed warnings on their labels, as well as developed Medication Guides for patients as was directed by the FDA in April 2009. The revised labels are being used to emphasize that the different botulinum toxin products are not interchangeable because the units used to measure the products are different. There has not been as of yet any reports of adverse effects when products are used as directed.

The new boxed warning cautions now on the product warn the patient that the effects of the botulinum toxin treatment may spread from the area of injection to other areas of the body which can cause symptoms similar to those of botulism. These symptoms can be potentially life threatening. Swallowing and breathing difficulties have been reported and in some cases death can occur. Such symptoms have mostly been reported in children with cerebral palsy who are being treated with botulinum toxin for muscle spasticity. This use of the drug has not been approved by the FDA. These symptoms have also been reported in adults treated for both approved and unapproved uses.


The four affected products are:

  • Botox (new established name: onabotulinumtoxinA)
  • Botox Cosmetic (new established name: onabotulinumtoxinA)
  • Myobloc (new established name: rimabotulinumtoxinB)
  • Dysport (abobotulinumtoxinA) is not making any name or label changes at this time.