Mechanisms of Botulinum Toxin Type A Action on Pain

Already a well-established treatment for different autonomic and movement disorders, the use of botulinum toxin type A (BoNT/A) in pain conditions is now continuously expanding. Currently, the only approved use of BoNT/A in relation to pain is the treatment of chronic migraines. However, controlled clinical studies show promising results in neuropathic and other chronic pain disorders. In comparison with other conventional and non-conventional analgesic drugs, the greatest advantages of BoNT/A use are its sustained effect after a single application and its safety. Its efficacy in certain therapy-resistant pain conditions is of special importance. Novel results in recent years has led to a better understanding of its actions, although further experimental and clinical research is warranted. Here, we summarize the effects contributing to these advantageous properties of BoNT/A in pain therapy, specific actions along the nociceptive pathway, consequences of its central activities, the molecular mechanisms of actions in neurons, and general pharmacokinetic parameters.

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Sustained effect of repeated botulinum toxin type A injections in trigeminal neuralgia

Neurology and Clinical Neuroscience ◽

10.1111/ncn3.12309 ◽

2019 ◽

Vol 7 (6) ◽

pp. 318-321 ◽

Cited By ~ 1

Author(s):

Bhavya Gorimanipalli ◽

Arunmozhimaran Elavarasi ◽

Vinay Goyal ◽

Chanchal Goyal ◽

Garima Shukla ◽

...

Keyword(s):

Botulinum Toxin ◽

Trigeminal Neuralgia ◽

Botulinum Toxin Type A ◽

Type A ◽

Botulinum Toxin Type ◽

Sustained Effect

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Synergic Effect of Botulinum Toxin Type-A and Triamcinolone Alleviates Scar Pruritus By Modulating Epidermal Hyperinnervation: A Preliminary Report

Aesthetic Surgery Journal ◽

10.1093/asj/sjab105 ◽

2021 ◽

Author(s):

Shu-Hung Huang ◽

Kuo-Wei Wu ◽

Jing-Jou Lo ◽

Sheng-Hua Wu

Keyword(s):

Botulinum Toxin ◽

Clinical Efficacy ◽

Molecular Mechanisms ◽

Transient Receptor Potential ◽

Botulinum Toxin Type A ◽

Type A ◽

Botulinum Toxin Type ◽

Nerve Fibers ◽

Therapeutic Interventions ◽

Transient Receptor Potential Vanilloid

Abstract Background Patients often experience scar-related pruritus, which negatively affects quality of life. Triamcinolone acetonide (TAC) is widely used to treat pathological scars, and botulinum toxin type-A (BTX-A) reportedly improves scarring and associated discomfort. Objectives To investigate the clinical efficacy of the combined TAC and BTX-A (TAC/BTX-A) in reducing scar itch and their potential mechanisms via animal model. Methods In a clinical study, each scar on a patient was divided into 2 equal parts, with one part receiving TAC/BTX-A and the other TAC alone. Therapeutic interventions were administered over 3 sessions, each 4 weeks apart. Itch intensity was measured using visual analogue scale before each therapeutic intervention (V1, V2, V3) and 4 weeks after the last intervention (V4). In a rat model, rats were allocated into 5 groups: control, untreated burn, TAC, BTX-A, and TAC/BTX-A groups. We evaluated alloknesis in the right hind paw and analyzed possible molecular mechanisms. Results In humans, TAC/BTX-A significantly reduced scar itch compared with TAC alone at V4 (p = 0.04). In rats, post-burn itch was mitigated at 4 weeks after treatment with TAC, BTX-A, and TAC/BTX-A (p = 0.03, p = 0.0054, and p = 0.0053, respectively). TAC/BTX-A significantly decreased the density of intraepidermal nerve fibers post-burn relative to the untreated burn (p = 0.0008). TAC/BTX-A downregulated the expressions of nerve growth factor (NGF) and protein transient receptor potential vanilloid subtype 1 (TRPV1). Conclusions TAC/BTX-A therapy exhibited enhanced and sustained clinical efficacy in relieving scar itch, possibly via modulating epidermal innervation and TRPV1 expression.

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