The FDA has announced changes to the safety label on botulinum toxin due to reports that the effects of the toxin may spread from the area of injection to other areas of the body causing serious adverse problems. This new label requirement is required on Botox and Botox Cosmetic (botulinum toxin type A); Myobloc (botulinum toxin type B); and a new FDA-approved product, Dysport (abobotulinumtoxinA).
When the botulinum toxin spreads beyond the area injected the toxin can cause symptoms similar to those of botulism. These symptoms include unexpected loss of strength or muscle weakness, hoarseness or trouble talking, trouble saying words clearly, loss of bladder control, trouble breathing, trouble swallowing, double vision, blurred vision and drooping eyelids.
Even though these adverse events have been reported in adults most have been reported in children with cerebral palsy. These adverse events have been reported in patients treated for approved and unapproved (off-label) uses.
All three products (Botox, Myobloc, and Dysport) are approved by the FDA for the treatment of cervical dystonia (a condition marked by repetitive contraction of the neck muscles). Botox Cosmetic and Dysport are approved for use in the temporary improvement in the appearance of glabellar frown lines. Botox is approved for the treatment of severe underarm sweating (primary axillary hyperhidrosis), crossed eyes (strabismus), and abnormal tics and twitches of the eyelids (blepharospasm). All other uses are considered off-label.
Risk Evaluation and Mitigation Strategy (REMS) will now be necessary for all botulinum toxin products. Currently, Dysport is the only one with an available REMS as it was part of their product approval. The companies that manufacture Botox and Myobloc have 30 days to submit the requested label changes. The FDA is also requiring the manufacturers to collect safety data in children and adults with muscle spasticity to assess the signal of risk regarding distant spread of toxin effects.
The companies that make Botox and Myobloc are required to submit the requested safety label changes, including the boxed warning and the Medication Guide, to the FDA within 30 days, or to provide a reason why they do not believe such changes are necessary. If they do not submit new language, or the FDA disagrees with the language the companies propose, the Food, Drug, and Cosmetic Act provides strict timelines for discussions regarding the changes. At the end of these discussions the agency is allowed to issue an order directing the label change as deemed appropriate to address the new safety information.
Physicians who use botulinum toxins should understand the dosage strengths and differences between the products. Patients and their families should be educated about the potential adverse effects. Both physicians and patients should understand that these effects have been reported as early as several hours and as late as several weeks after treatment.
Health care professionals and consumers may report serious adverse events (side effects) or product quality problems with the use of this product to the FDA's MedWatch Adverse Event Reporting program either online, by regular mail, fax or phone.
-- Online: www.fda.gov/MedWatch/report.htm
-- Regular Mail: use postage-paid FDA form 3500 available at: www.fda.gov/MedWatch/getforms.htm and mail to MedWatch, 5600 Fishers Lane, Rockville, MD 20852-9787
FDA News (April 30, 2009)