Current Clinical Applications of Botulinum Toxin

Abstract

Botulinum toxin has long been known for its paralytic effects on the human voluntary musculature via inhibition of acetylcholine release at neuromuscular junctions. Its original clinical use for the treatment of strabismus has expanded significantly to include neurological conditions related to muscle hyperactivity and/or spasticity (e.g., dystonia, spasticity, tics, tremor, dysphonia). Recently, botulinum toxin has been shown to impact autonomic disorders by acting at acceptors on glands and smooth muscle, and consequently it has been used in the management of a number of other conditions including hypersecretory disorders, pain syndromes, detrusor sphinchter dyssenergia or overactivity and gastointestinal smooth muscle/sphincter spasm; it may also reduce pain in patients for whom it is used to treat these and other primary conditions. This article will review the pharmacology and formulations of botulinum toxins as well as data from clinical trials demonstrating their efficacy for numerous conditions based on their effects on cholinergic synapses outside the motor nervous system.

Botulinum toxin A, brain and pain

“…Presently, BoNT/A is produced by over 20 manufacturers in US, Europe, and other parts of the world (Truong et al, 2009). Potency units for each of the BoNT products are specific, and cannot be compared or converted between different products.…”

Characterization of Botulinum Neurotoxin A Subtypes 1 Through 5 by Investigation of Activities in Mice, in Neuronal Cell Cultures, and In Vitro

“…Currently, the Food and Drug Administration (FDA) has approved two serotypes, A1 (abo-, ona-, and incobotulinumtoxin A) and B1 (rimaotulinumtoxin B), for treatment of various indications in humans. BoNT/A1 is the predominant serotype of botulinum neurotoxin used for pharmaceutical applications (8,9) and is the best-studied BoNT. Its extraordinary potency (10), its long duration of action, and its localized activity in the inhibition of neuromuscular activity upon intramuscular injection have contributed to the use of BoNT/A as a valuable pharmaceutical for treatment of a variety of clinical as well as aesthetic applications (reviewed in reference 11).…”

Behavioral and immunohistochemical evidence for central antinociceptive activity of botulinum toxin A

“…Apart from its well known therapeutic use in muscular hyperactivity and certain autonomic disorders (Ward et al, 2006, Truong et al, 2009, botulinum toxin A (BTX-A) was recently registered for migraine treatment (Dodick et al, 2010). Besides migraine, its beneficial effects not associated with cholinergic neurotransmission were reported in cluster headache, neuropathic pain, joint pain, back pain, etc (Querama et al, 2010).…”