Botulinum toxin the poison that heals: A brief review

Botulinum neurotoxins, causative agents of botulism in humans, are produced by Clostridium botulinum, an anaerobic spore-former Gram-positive bacillus. Botulinum neurotoxin poses a major bioweapon threat because of its extreme potency and lethality; its ease of production, transport, and misuse; and the need for prolonged intensive care among affected persons. This paper aims at discussing botulinum neurotoxin, its structure, mechanism of action, pharmacology, its serotypes and the reasons for wide use of type A, the various indications and contraindications of the use of botulinum neurotoxin and finally the precautions taken when botulinum neurotoxin is used as a treatment approach. We have searched relevant articles on this subject in various medical databases including Google Scholar, PubMed Central, ScienceDirect, Wiley Online Library, Scopus, and Copernicus. The search resulted in more than 2669 articles, out of which a total of 187 were reviewed. However, the review has been further constricted into only 54 articles as has been presented in this manuscript keeping in mind the page limitation and the limitation to the number of references. A single gram of crystalline toxin, evenly dispersed and inhaled, can kill more than one million people. The basis of the phenomenal potency of botulinum toxin (BT) is enzymatic; the toxin is a zinc proteinase that cleaves neuronal vesicle-associated proteins responsible for acetylcholine release into the neuromuscular junction. A fascinating aspect of BT research in recent years has been the development of the most potent toxin into a molecule of significant therapeutic utility. It is the first biological toxin which is licensed for the treatment of human diseases. The present review focuses on both warfare potential as well as medical uses of botulinum neurotoxin.