Botulinum Toxin Safety Warnings Updated and Name Changes Issued

Emma Hitt


August 04, 2009

August 4, 2009 — The US Food and Drug Administration (FDA) has announced revisions to both the prescribing information and the names of botulinum toxin products.

An alert sent yesterday from MedWatch, the FDA's safety information and adverse event reporting program, describes updates to previous safety alerts on 4 botulinum toxin drug products, noting that all of them now have boxed warnings on their labels. In addition, medication guides have been issued for patients, as directed by the agency in April 2009.

The following revisions to the prescribing information of Botox/Botox Cosmetic (Allergan, Inc) and Myobloc (Solstice Neurosciences, Inc) have been made: a boxed warning now highlights the possibility of experiencing potentially life-threatening distant spread of toxin effect from the injection site after local injection, and, a risk evaluation and mitigation strategy that includes a patient-directed medication guide has been issued. Changes also have been made to the established drug names to reinforce individual potencies and prevent medication errors.

Established name changes for the 4 botulinum toxin products are as follows:

  • Botox/Botox Cosmetic: new name: onabotulinumtoxinA; old name: botulinum toxin type A

  • Dysport (Medicis Pharmaceutical Corporation): new name: abobotulinumtoxinA; old name: botulinum toxin type A (approved April 29, 2009)

  • Myobloc: new name: rimabotulinumtoxinB; old name: botulinum toxin type B

"The potency units are specific to each botulinum toxin product, and the doses or units of biological activity cannot be compared or converted from one product to any other botulinum toxin product," the FDA notes. "The new established names reinforce these differences and the lack of interchangeability among products," the agency adds.

According to an FDA press release, symptoms associated with distant spread of toxin effect from the injection site have been reported mostly in children with cerebral palsy being treated for muscle spasticity, a nonapproved use of the drug. "Symptoms have also been reported in adults treated both for approved and unapproved uses," the FDA states. However, no definitive serious adverse event reports of distant spread of toxin effect have been associated with dermatologic uses such as glabellar lines or hyperhidrosis.

More information is available on the MedWatch Web site.

Adverse events related to use of botulinum toxin products should be communicated to MedWatch by telephone at 1-800-FDA-1088, by fax at 1-800-FDA-0178, online at, or by mail to 5600 Fishers Lane, Rockville, Maryland 20852-9787.