BOTOX® injections are noted primarily for the ability to reduce the appearance of facial wrinkles. They're also used to treat conditions such as neck spasms (cervical dystonia), excessive sweating (hyperhidrosis), an overactive bladder and lazy eye. BOTOX® injections may also help prevent chronic migraines. Botox® injections use a toxin called onobotulinumtoxinA to temporarily prevent a muscle from moving. This toxin is produced by the microbe that causes botulism, a type of food poisoning. BOTOX® was the first drug to use botulinum toxin. Other products now include abobotulinumtoxinA (Dysport®), rimabotulinumtoxinB (Myobloc) and incobotulinumtoxinA (Xeomin®). Each is a little different, particularly when it comes to dosage units, so they aren't interchangeable.
These substances target the nervous system, disrupting the nerve signaling processes that stimulate muscle contraction. This is how the drug causes temporary muscle paralysis. In order for any muscle to contract, the nerves release a chemical messenger called acetylcholine at the junction where nerve endings meet muscle cells. Acetylcholine attaches to receptors on the muscle cells and causes the cells to contract, or shorten. Toxin injections prevent the release of acetylcholine, which stops the muscle cells from contracting. In this way, the toxin helps the muscles to become less stiff.