Eric A. Johnson

CHAPTER 58 – Medical applications of botulinum neurotoxins

During the past decade, the pharmaceutical utility of botulinum toxin complex (BTX) has extended to a variety of disorders that do not have an apparent origin in hyperactive synaptic cholinergic activity. These include various pain disorders, inflammatory conditions, and autonomic syndromes. Drawbacks and side effects to BTX use are formation of antibodies in a subset of patients and undesirable spread from the targeted area. Systemic complications have been rare. BTX consists of non-toxic proteins non-covalently linked with the biologically active botulinum neurotoxin (BoNT). Advances in understanding of the biochemistry, structure, and cellular biology of BoNTs have provided leads to improve the efficacy of BoNT as a drug and application to new indications. This chapter describes the scientific basis for BTX and BoNT as pharmaceuticals and describes clinical aspects of the toxin. It also presently has some disadvantages, such as spread to neighboring muscles, requirement for repeated injections, lack of consistency of biological activity, and antibody formation with improper use. It is likely that many of these disadvantages will be overcome as the physiology in relation to the human body is better understood and new generation botulinum drugs are developed. Despite its current shortcomings, it has benefited thousands of humans and allowed them to live normal and healthy lives.