William J. Binder reported in 2000 that patients who had cosmetic injections around the face reported relief from chronic headache.[57] This was initially thought to be an indirect effect of reduced muscle tension, but it is now known that the toxin inhibits release of peripheral nociceptive neurotransmitters, suppressing the central pain processing systems responsible for migraine headache.[58][59]
Hoffman’s husband’s experience is not unusual. Once a patient gets the more expensive prescription, health insurance providers can still try and push them back to cheaper drugs. Brigham and Women’s Hospital’s Loder says that most health insurance companies stop paying for Botox if it’s not reducing a patient’s migraines by at least 50 percent. “It’s important to keep careful headache diaries and keep careful notes in order to be able to prove to the insurance company that the treatment is worth it,” Loder says. “You’re not home free once they approve it.”

Focal Spasticity is a condition in which certain muscles in your body become stiff or tight. It is caused by damage to parts of the central nervous system that control voluntary movements. When this happens, your nerves send continuous messages to your muscles telling them to contract, or tighten. If you or someone you care for has stiffness in the muscles of the elbow, wrist, fingers, thumb, ankle, or toes, it could be Focal Spasticity.1
Botulinum toxin is used to treat a number of disorders characterized by overactive muscle movement, including post-stroke spasticity, post-spinal cord injury spasticity, spasms of the head and neck,[8] eyelid,[9] vagina,[10] limbs, jaw, and vocal cords.[11] Similarly, botulinum toxin is used to relax clenching of muscles, including those of the oesophagus,[12] jaw,[13] lower urinary tract and bladder,[14] or clenching of the anus which can exacerbate anal fissure.[15] It may also be used for improper eye alignment.[16] Botulinum toxin appears to be effective for refractory overactive bladder.[17]
The potency Units of BOTOX are specific to the preparation and assay method utilized. They are not interchangeable with other preparations of botulinum toxin products and, therefore, units of biological activity of BOTOX cannot be compared to nor converted into units of any other botulinum toxin products assessed with any other specific assay method [see DESCRIPTION].
Proper refrigeration at temperatures below 3 °C (38 °F) retards the growth of Clostridium botulinum. The organism is also susceptible to high salt, high oxygen, and low pH levels.[citation needed] The toxin itself is rapidly destroyed by heat, such as in thorough cooking.[72] The spores that produce the toxin are heat-tolerant and will survive boiling water for an extended period of time.[73]

In response to the occurrence of these side effects, in 2008 the U.S. Food and Drug Administration notified the public of the potential dangers of the botulinum toxin as a therapeutic. Namely, they warned that the toxin can spread to areas distant from the site of injection and paralyze unintended muscle groups, especially when used for treating muscle spasticity in children treated for cerebral palsy.[28] In 2009, the FDA announced that boxed warnings would be added to available botulinum toxin products, warning of their ability to spread from the injection site.[29] Additionally, the FDA announced name changes to several botulinum toxin products, meant to emphasize that the products are not interchangeable and require different doses for proper use. Botox and Botox Cosmetic were renamed onabotulinumtoxinA, Myobloc was renamed rimabotulinumtoxinB, and Dysport name renamed abobotulinumtoxinA.[29] In conjunction with this, the FDA issued a communication to health care professionals reiterating the new drug names and the approved uses for each.[30] A similar warning was issued by Health Canada in 2009, warning that botulinum toxin products can spread to other parts of the body.[31]
Ophthalmologists specializing in eye muscle disorders (strabismus) had developed the method of EMG-guided injection (using the electromyogram, the electrical signal from an activated muscle, to guide injection) of local anesthetics as a diagnostic technique for evaluating an individual muscle’s contribution to an eye movement.[44] Because strabismus surgery frequently needed repeating, a search was undertaken for non-surgical, injection treatments using various anesthetics, alcohols, enzymes, enzyme blockers, and snake neurotoxins. Finally, inspired by Daniel Drachman’s work with chicks at Johns Hopkins,[45] Alan B Scott and colleagues injected botulinum toxin into monkey extraocular muscles.[46] The result was remarkable: a few picograms induced paralysis that was confined to the target muscle, long in duration, and without side-effects.
Though there's still more research to be done on Botox for migraines and doctors aren't yet completely sure why the procedure is effective, they have some ideas. Ravitz tells me, "What [Botox] does is paralyze nerve terminals. Essentially, nerve terminals transmit pain, but they also produce pain substances while they’re doing that, and it completely paralyzes that process." She says that it stops the process of pain patterning and it also relaxes the muscles.
It is not known whether BOTOX® is safe or effective to treat increased stiffness in upper limb muscles other than those in the elbow, wrist, fingers, and thumb, or in lower limb muscles other than those in the ankle and toes. BOTOX® has not been shown to help people perform task-specific functions with their upper limbs or increase movement in joints that are permanently fixed in position by stiff muscles. Treatment with BOTOX® is not meant to replace existing physical therapy or other rehabilitation that may have been prescribed.