The Clinical journal of pain
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Botulinum toxin has dramatically improved the treatment of a variety of neurologic disorders. Two botulinum toxin preparations are commercially available in the United States: type A (Botox) and type B (Myobloc). ⋯ This mechanism enables botulinum toxin to alleviate symptoms of focal dystonias (which are characterized by excessive muscle contraction), and it may also, along with other theoretical mechanisms, be responsible for pain relief. Studies conducted in patients with cervical dystonia have shown that botulinum toxin effectively reduces pain associated with this disorder, suggesting that this agent may be effective in alleviating other painful syndromes.
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Botulinum toxin has been shown to effectively treat several types of pain associated with neurologic disorders. It has recently been evaluated for the treatment of various types of headaches. In studies of migraine headache, chronic daily headache (more than 15 days of headache per month), tension-type headache, and post-whiplash headache, patients have reported decreased pain after treatment with botulinum toxin type A. ⋯ It may also provide peripheral and central neurogenic effects and reduce inflammation. Large, rigorously controlled trials of botulinum toxin are needed to better characterize its effects on various types of headaches and its role as a therapeutic agent. Current data suggest that botulinum toxin is safe and does not produce systemic effects associated with other types of headache treatments.
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The seven botulinum neurotoxin serotypes share less than 50% sequence homology and are immunologically distinct. The neurotoxins inhibit release of the neurotransmitter acetylcholine from the axon terminals of motor neurons, preganglionic sympathetic and parasympathetic neurons, and postganglionic parasympathetic nerves by a multi-step mechanism that differs slightly, but significantly, for each serotype. ⋯ The resulting muscle paralysis has provided the basis for therapeutic use of botulinum toxin types A and B in a variety of focal dystonias. The safety of the botulinum toxins, when administered focally, has permitted their widespread use in a number of other painful conditions.
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The immune system is unable to determine whether material it encounters is deleterious, benign, or even beneficial to the organism. This presents a significant challenge when protein-based biological therapies, such as botulinum toxin, are administered to patients. Many factors combine to influence the likelihood and the magnitude of an immune response if a response is elicited. ⋯ The majority of anti-toxin antibodies do not affect its function. Finally, although crossreactivity has been reported among the seven botulinum toxin serotypes, non-neutralizing antibodies are present that recognize regions of similarity among the serotypes. No cross-neutralizing antibodies have been described in patients administered any of the toxin serotypes.
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Temporomandibular disorder (TMD) is a collective term used to characterize a heterogeneous group of conditions involving the temporomandibular joint (TMJ) and its contiguous tissues. Although the pathologies behind TMDs have not been completely explained, the symptoms associated with these disorders are similar and are most commonly manifest as pain in the orofacial region. ⋯ This article describes common TMDs and their treatment with botulinum toxin. Dosing guidelines and illustrations of affected muscles and target injection sites are provided.