ABSTRACT
INTRODUCTION Clinical use of botulinum neurotoxins has virtually exploded over the past 40 years, and these biologic agents now provide relief for millions with focal dystonia and spasticity. OnabotulinumtoxinA (BOTOX®, Allergan, Irvine, CA, USA) is a purifi ed botulinum neurotoxin type A complex that inhibits acetylcholine release into the synaptic cleft, producing focal reduction in pathological overactivity (1-3). Initially available in the USA in 1989 for the treatment of VII nerve disorders and blepharospasm as Oculinum®, the trade name was soon changed to BOTOX. Since that time, onabotulinumtoxinA has been rigorously studied, with 50 randomized controlled trials in over 11,000 patients confi rming long-term effi cacy and safety. Potential uses continue to emerge (4-10), and 21 separate indications have been approved by regulatory agencies worldwide, most recently for the treatment of chronic migraine headaches in adults (Table 27.1).
