Pearls and pitfalls in the therapeutic use of botulinum toxin.

Botulinum toxin is a potent toxin and powerful therapeutic tool. Botulinum toxin has therapeutic application in the treatment of a host of neurological, ophthalmologic, gastroenterological, urologic, and dermatologic conditions. Although there are issues specific to each disorder for which botulinum toxin therapy is employed, there are several common principles. This article reviews several of these general principles by addressing common questions that arise in the therapeutic use of botulinum toxin. Areas of focus include patient selection, drug preparation and delivery, use of electromyography to guide injections, drug resistance, and organization of a therapeutic botulinum toxin clinic.