Future aspects of botulinum neurotoxins.

The future of botulinum neurotoxin (BoNT) development is expected to proceed along two lines: the development of novel indications and the development of novel products. New indications will likely be based on the neuromuscular mode of action of BoNTs, as well as action on primary sensory fibers and other neuronal types. Novel BoNT products may be designed for increased specificity or enhanced duration. As new products enter the market, it will be important for each to demonstrate efficacy and safety. Unfortunately, the future of BoNTs will also likely include attempts to obtain and distribute unlicensed and illegal BoNT products that may pose substantial risks to patients.