Last month, we reported that the FDA was requiring stronger warnings on four types of botulinum toxin drug products. The most popular of the drugs affected by the warning change is Botox, which is commonly used in the United States for the off-label use of smoothing wrinkles. The FDA announced yesterday that all four of the botulinum toxin drug products now have a black box warning label on them.

The new warning cautions that the toxin used in the drugs, which is a variant of the bacteria that causes botulism, can migrate from the injection site to other areas of the body and can potentially cause symptoms similar to those experienced from botulism. The migration has mostly been reported when children with cerebral palsy are treated with the drug for muscle spasticity, an off-label use of the drug. In those children, the migration can cause severe adverse effects such as trouble swallowing and trouble breathing. No serious adverse effects have been reported from migration when the drugs are used for dermatologic purposes.

The new labels also caution health professionals that the four different types of botulinum toxin drugs are not interchangeable, because the units to measure each of the drugs are different. To help reduce the potential for dosing errors, the drugs have changed their established drug names (their generic names).

For more information, see the FDA Press Release at:
http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm175013.htm

See the Drug Safety Information for Patients and Providers at:
http://www.fda.gov/Drugs/DrugSafety/PostmarketDrugSafetyInformationforPatientsandProviders/DrugSafetyInformationforHeathcareProfessionals/ucm174949.htm

See the update of Safety Review for Patients and Providers at:
http://www.fda.gov/Drugs/DrugSafety/PostmarketDrugSafetyInformationforPatientsandProviders/DrugSafetyInformationforHeathcareProfessionals/ucm174959.htm

Labels: Botox, botulinum toxin, botulism, cerebral Palsy, FDA

The FDA announced yesterday that all botulinum toxin products will now require a black box warning for safety purposes. The agency decided to require a stronger warning due to interchangeability problems among the 3 main botulinum drugs and serious adverse events that were being reported. Many of the adverse events reported concerned that the botulinum toxin could spread from the injection site to other areas of the body, causing symptoms similar to those of botulism. Some of these symptoms include: unexpected loss of strength or muscle weakness, trouble talking and saying words clearly, loss of bladder control, trouble breathing, trouble swallowing, double/blurred vision, and droopy eyelids. Most of these symptoms have been reported in children that take botulinum drugs for cerebral palsy, but some symptoms have been reported by adults that use botulinum for both FDA approved and unapproved uses.

The products that the FDA is requiring to adopt a new label are:
Botox and Botox Cosmetic
Myobloc
Dysport

All three drugs are FDA approved to treat cervical dystonia, a condition where the muscles in the neck constantly contract. Botox Cosmetic and Dysport are used to temporarily treat “frown lines” between the eyebrows. Also Botox is used for severe underarm sweating, crossed eyes, and abnormal tics of the face. Treatment of muscle spasticity for cerebral palsy is not an FDA approved use of any of the three botulinum drugs.

The FDA wants healthcare professionals to understand that that dosage strength is not interchangeable between the three drugs. A dose in one of the botulinum drugs may be more potent than a dose of another botulinum drug. Also, adverse events have been reported as little as a few hours after the drugs were administered to as long as several weeks after the drugs have been administered.

Anyone who has experienced adverse experiences from the use of the drug should report it to the FDA.

For more information, see the FDA warning page:
http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm149574.htm

See also the FDA’s response to the Citizen Petition at:
http://www.fda.gov/cder/drug/early_comm/botulinum_CP_response.pdf

Labels: Black box label, Botox, botulism, Dysport, FDA, Myobloc, warning