Botulinum Toxin Injection for Chronic Migraine
Botulinum Toxin A has been approved by the Federal Drug Administration for treatment of chronic migraine in individuals 18 years of age and older. Botulinum toxin does not cure chronic migraine and it may not be effective in some patients. There have, however, been no serious injuries or deaths resulting from its use in chronic migraine.
Administration of botulinum toxin is performed by injecting a small amount of botulinum toxin into the muscles of the head and neck. Any benefits resulting from botulinum toxin tend to wear off after about 3 months, with a repeat injection required if benefit is to be maintained. Injections are usually done every 12 weeks with maximal effect peak achieved by about 2-3 weeks. Botulinum toxin is expensive and you should be sure of what costs you will incur from the injections.
The side effects of botulinum toxin used for chronic migraine may include:
- Temporary transient, and usually mild, facial weakness with facial injections
- Transient, and usually mild, head or neck weakness with head/neck injections
- Reduction or loss of forehead facial animation due to forehead muscle weakness
- Eyelid drooping (ptosis) – although this is rare
- Pain at the site of the injection or ecchymosis (bruising) at the site of injection
- Dry eye
- Double vision
- Potential unknown long-term risks
It is also possible that as with any injection, there may be an allergic reaction or no effect from the medication. Reduced effectiveness after repeated injections is sometimes seen. All care will be taken to prevent these side effects. If therapy is given over a long period of time, atrophy and wasting in the injected muscle may occur. Occasionally patients become refractory to treatment because they developed antibodies to the toxin. I n this event, therapy needs to the modified.