title: Botulinum toxin in pain treatment.
abstract: OBJECTIVE
  Botulinum toxin (BTX) is one of the most potent bacterial toxins known and its effectiveness in the treatment of some pain syndromes is well known. However, the efficacy of some of its indications is still in the process of being confirmed. The objective of this study was to review the history, pharmacological properties, and clinical applications of BTX in the treatment of pain of different origins.
  
  
  BACKGROUND
  Botulinum toxin is produced by fermentation of Clostridium botulinum, a Gram-positive, anaerobic bacterium. Commercially, BTX comes in two presentations, types A and B. Botulinum toxin, a neurotoxin with high affinity for cholinergic synapses, blocks the release of acetylcholine by nerve endings without interfering with neuronal conduction of electrical signals or synthesis and storage of acetylcholine. It has been proven that BTX can selectively weaken painful muscles, interrupting the spasm-pain cycle. Several studies have demonstrated the efficacy and safety of BTX-A in the treatment of tension headaches, migraines, chronic lumbar pain, and myofascial pain.
  
  
  CONCLUSIONS
  Botulinum toxin type A is well tolerated in the treatment of chronic pain disorders in which pharmacotherapy regimens can cause side effects. The reduction in the consumption of analgesics and length of action of 3 to 4 months per dose represent other advantages of its use. However, further studies are necessary to establish the efficacy of BTX-A in chronic pain disorders and its exact mechanism of action, as well as its potential in multifactorial treatments.
authors.affiliation: Doutorando em Ciências Médicas pela USP de Ribeirão Preto. esperanssoli@uol.com.br
authors.forename: Orlando Carlos Gomes
authors.initials: OC
authors.lastname: Colhado
authors.forename: Marcelo
authors.initials: M
authors.lastname: Boeing
authors.forename: Luciano Bornia
authors.initials: LB
authors.lastname: Ortega
mesh_terms: D000109:Acetylcholine / Q000378:metabolism; D019274:Botulinum Toxins, Type A / Q000494:pharmacology / Q000627:therapeutic use*; D006801:Humans; D009465:Neuromuscular Agents / Q000494:pharmacology / Q000627:therapeutic use*; D010146:Pain / Q000188:drug therapy*
chemical_list: D009465:Neuromuscular Agents; D019274:Botulinum Toxins, Type A; D000109:Acetylcholine