Botulinum toxin is a powerful medication that has been used to treat various conditions in humans for several decades. In the last few years, there has been an explosion in the use of this drug for cosmetic purposes. Millions have benefited from the therapeutic effects of botulinum toxin, with very few patients experiencing adverse effects. In this chapter, we will discuss the various techniques and therapeutic uses of botulinum toxin in the field of cosmetic dermatology.

MECHANISMS OF ACTION

The mechanism of action of botulinum toxin (BTX) has been well established (Sakaguchi 1983; Carruthers and Carruthers 1992; Keen et al. 1994; Hambleton 1992). Protein interactions at the neuromuscular junction prevent the release of acetylcholine. There are seven known antigenically distinct serotypes of BTX (A–G). The most widely used and studied is botulinum toxin type A (BTX-A). This protein irreversibly binds and cleaves the SNAP-25 protein. There are currently two available preparations of BTX-A on the U.S. market: Botox and Dysport. Botulinum toxin type B (BTX-B) binds to synaptobrevin. BTX-B is available commercially as Myobloc. The temporary nature of therapeutic BTX therapy is due to axonal sprouting at the motor end plate of the neuromuscular junction as well as the development of extrajunctional acetylcholine receptors (de Paiva et al. 1999). This occurs over several months after BTX therapy.

COSMETIC USE

Cosmetic BTX treatments have become one of the most common nonsurgical procedures performed by dermatologists and plastic surgeons.