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Since the 1980s, botulinum toxins (BTX) have been used for many
putative conditions that cause pain. The U.S. Food and Drug Administration
(FDA) has not yet approved their use for any specific pain disorders,
although two forms of BTX (A and B) have been approved by the FDA
for other medical conditions associated with pain and discomfort.
However, BTX continues to be used successfully by a range of specialists
to address pain control.
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Although there are many case reports and open-label studies on
the effectiveness of BTX in treating painful conditions, a dearth
of double-blind, placebo-controlled, randomized clinical trials exist
that directly addresses its use for pain management. Some double-blind,
placebo-controlled, randomized clinical studies show that botulinum
toxin type A (BTX-A) injections are effective in treating various
headache disorders (Table 23-1). However, there are no published
clinical trials showing its effectiveness in cluster headaches.
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All of the data presented in this chapter, and most of the published
experience in headache management is from BTX-A studies, but botulinum
toxin type B (BTX-B) also may be effective, given the similarity
of the two serotypes.
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Headache is one of the most common types of pain disorder, responsible
for more than 10 million physician visits annually in the United
States. Although the terminology of various types of headaches may
be confusing, we limit our discussion here to primary headaches,
for which BTX data is available to make preliminary recommendations
until more information is available from ongoing large, multi-center,
double-blind, randomized, placebo-controlled trials.
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Migraine is a neurologic disorder that features recurrent attacks
of headache, most often occurring unilaterally. It accompanies various
combinations of symptoms, such as nausea, vomiting, and sensitivity
to light, sound, and other stimuli. Migraine attacks can occur at
any time of day or ...