Researchers discovered in the 1950s that injecting overactive muscles with minute quantities of botulinum toxin type-A would result in decreased muscle activity by blocking the release of acetylcholine from the neuron by preventing the vesicle where the acetylcholine is stored from binding to the membrane where the neurotransmitter can be released. This will effectively weaken the muscle for a period of three to four months.
In cosmetics, a Botox injection, consisting of a small dose of botulinum toxin, can be used to prevent formation of wrinkles by paralyzing facial muscles. As of 2007, it is the most common cosmetic operation, with 4.6 million procedures in the United States, according to the American Society of Plastic Surgeons. Qualifications for Botox injectors vary by county, state and country. Botox cosmetic providers include dermatologists, plastic surgeons, cosmetic physicians, nurse practitioners, nurses, physician assistants, and medical spas. The wrinkle preventing effect of Botox lasts for approximately three to four months, upto six months.
In addition to its cosmetic applications, Botox is currently used in the treatment e.g. spasms and dystonias, by weakening involved muscles, for the 60-70 day effective period of the drug. The main conditions are:
Cervical dystonia (spasmodic torticollis) (a neuromuscular disorder involving the head and neck)
Blepharospasm (excessive blinking)
Severe primary axillary hyperhidrosis (excessive sweating)
Achalasia (failure of the lower oesophageal sphincter to relax)
Local intradermal injection of BTX-A is helpful in chronic focal painful neuropathies. The analgesic effects are not dependent on changes in muscle tone.
Migraine and other headache disorders, although the evidence is conflicting in this indication
Other uses of botulinum toxin type A that are widely known but not specifically approved by FDA (off-label uses) include treatment of:
Pediatric incontinence, incontinence due to overactive bladder, and incontinence due to neurogenic bladder.
Anal fissure vaginismus To reduce the spasm of the vaginal muscles.
Spastic disorders associated with injury or disease of the central nervous system including trauma, stroke, multiple sclerosis, Parkinson’s disease, or cerebral palsy.
Focal dystonias affecting the limbs, face, jaw, or vocal cords.
TMJ pain disorders
Vocal cord dysfunction (VCD) including spasmodic dysphonia and tremor
Reduction of the Masseter muscle for decreasing the size of the lower jaw
Treatment and prevention of chronic headache and chronic musculoskeletal pain are emerging uses for botulinum toxin type A. In addition, there is evidence that Botox may aid in weight loss by increasing the gastric emptying time.