Overview of Botox
Botulinum toxin injection therapy (also known as “BOTOXÂ® therapy” or onabotulinumtoxinA) is used to treat dystonia â€” a neuromuscular disorder that produces involuntary muscle contractions, or spasmâ€”that affects muscles that control movement in the eyes, neck, face, limbs, voice box, or the smooth muscle in the bladder. The goal of the therapy is to reduce muscle spasm and pain.
In October 2010, the U.S. Food and Drug Administration (FDA) approved BOTOX injections to treat chronic migraines in adults who experience headaches on 14 or more days each month. This treatment involves multiple injections in the head and neck, administered every 12 weeks.
Botulinum toxin is a neurotoxin is produced by Clostridium botulinum, a bacterium that causes food poisoning (botulism). There are seven known types of C. botulinum toxin, but only types A; (BOTOXÂ® Cosmetic) and B (MyoblocÂ®) are used as medical treatments.Botulinum toxin has proven to be useful in the treatment of many forms of dystonia, including the following:
- blepharospasmâ€“forceful involuntary closure of the eyelids
- strabismusâ€“misalignment of the eyes
- hemifacial spasmâ€“sudden contraction of the muscles on one side of the face
- spasmodic torticollis, or cervical dystoniaâ€“muscle spasm in the neck that causes the head to turn to one side, and sometimes forward or backward
- oromandibular dystoniaâ€“continuous spasms of the face, jaw, neck, tongue, larynx, and in severe cases, the respiratory system
- urinary retentionâ€“severe inability to urinate that requires catheterization
- spasmodic dysphoniaâ€“spasm of the vocal cords that causes sudden disruption of speech
- stutteringâ€“repetitions of parts of words and whole words, long pauses, elongated sounds
- voice tremorâ€“quavering vocalization
- limb spasticity (e.g., following stroke )
Neurons generate new nerve endings that reactivate the dystonia, so improvement is not long lasting, and treatment is usually repeated every 3 to 4 months. Physical or occupational therapy usually is undertaken to stretch and restore normal muscle function. Some patients develop antibodies to the toxin over time, rendering the treatment ineffective.