BOTOX® (onabotulinumtoxinA) is a prescription medicine that is injected into muscles and used to prevent headaches in adults with chronic migraines.
Also referred to as Botulinum toxin, it is a neurotoxin produced by clostridium botulinum, the bacteria that thrive in poorly sterilized canned food and produces the severe food poisoning called botulism. This is the toxin that paralyzes nerves by blocking the release of a substance called acetylcholine – which blocks the muscles and prevents them from contracting thereby causing paralysis. The substance which is ingested in spoiled food and causes the illness is known as botulism.
However, in therapeutic uses, Botox is injected directly into the muscle rather than absorbed into the bloodstream. The dose is a fraction of that which causes botulism.
Botox is well known for its use in treatment of wrinkles. It has approval for use in treating facial tics and spasms, dystonia and other forms of spasticity in cerebral palsy for example. Its tolerability and safety record for these uses are excellent. The principle behind its use in this case, is to relax tense or spastic muscles by blocking Acetylcholine release which stimulates muscle contraction.
“The discovery of Botox for treatment of migraine was quite by accident”
The discovery of Botox for treatment of migraine was quite by accident. Several patients who were using Botox for injection of wrinkles also happened to have migraine. They reported improvement in their headaches following injection of Botox to their brow and forehead muscles.
Safety is always a concern. However, Botox’ record since 1989 is excellent. There is no systemic absorption as there is with oral medication; therefore no systemic side-effects are seen. Drooping eyelids can occur with improper injection techniques, but these are transient. Botox can be considered in patients when other migraine treatments fail or are contradicted. Cost depends on the number of units required. Safety and tolerability are excellent. Studies are ongoing to prove efficacy.
At present the use of Botox® is restricted to a few specialist headache centres, but as time goes on there should be increasing numbers of trained injectors available. In all cases, however, you should ensure that the person injecting has received appropriate training, both in the diagnosis and management of chronic migraine, and in the delivery of Botox®.