[Use of botulinum neurotoxin therapy].

Botulinum neurotoxins (BoNTs), produced by the gram-positive anaerobic bacterium Clostridium botulinum, act on motor nerve endings and induce muscle relaxation. BoNT type A and B are used as therapeutic agents. Several preparations of BoNT type A are commercially available; Botox®, Dysport®, and Xeomin® are popular. They differ in the manufacturing method used, for example, BoNT consists of neurotoxin and a complex protein, Botox® and Dysport® contain a complex protein, whereas Xeomin® is free from the protein. However, when applied clinically, there is no significant difference in the efficacy and adverse effects between these BoNT products. Intramuscular BoNT injection is widely recognized as a safe and effective treatment for blepharospasm, hemifacial spasm, cervical dystonia, spasticity, squint, migraine, hyperhidrosis, wrinkles (cosmetic purpose), achalasia, hyperactive bladder, etc. BoNT preparations are used in more than 70 countries. In Japan, BoNT is used to treat blepharospasm, hemifacial spasm, cervical dystonia, and spasticity in addition to being used to treat wrinkles. However, its use is not yet widespread in Japan. This article reviews the structure and characteristics of BoNT, and throws light upon the technique of injecting BoNT.