Article

Botulinum toxin type A (BTX-A) is a potent neurotoxin that blocks acetylcholine release from presynaptic nerve terminals by cleaving the SNARE complex.
BTX-A has been reported to have analgesic effects independent of its action on muscle tone.
The most robust results have been observed in patients with neuropathic pain.
Neuropathic pain due to peripheral lesions has been the most widely studied.
BTX-A has shown its efficacy on pain and allodynia in various animal models of
inflammatory neuropathic pain. The only randomized, double-blind,
placebo-controlled trial in patients with focal painful neuropathies due to nerve
trauma or postherpetic neuralgia demonstrated significant effects on average pain
intensity from 2 weeks after the injections to 14 weeks. Most patients reported
pain during the injections, but there were no further local or systemic side
effects. The efficacy of BTX-A in painful peripheral neuropathies has been more
recently studied. Results were positive in the only study in an animal model of
peripheral neuropathy. One study in patients with diabetic painful peripheral
neuropathy demonstrated a significant decrease in Visual Analog Scale. In
conclusion, one session of multiple intradermal injection of BTX-A produces
long-lasting analgesic effects in patients with focal painful neuropathies and
diabetic neuropathic pain, and is particularly well tolerated. The findings are
consistent with a reduction of peripheral sensitisation, the place of a possible
central effect remaining to define. Further studies are needed to assess some
important issues, i.e. BTX-A efficacy in patients with small fiber neuropathies
and the relevance of early and repeated injections. Future studies could also
provide valuable insights into pathophysiology of neuropathic pain.
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Langue : FRANCAIS