Availability

Currently, four commercially available sources of the purified protein of botulinum toxin are available. Three sources contain type A: (1) Botox Medical and (2) Botox Cosmetic are available worldwide from Allergan (Irvine, CA, USA); (3) Dysport, from Speywood Pharmaceuticals (Spotsylvania, VA, USA), is available in many parts of the world but not currently in the United States.The fourth source,Myobloc, from Elan Pharmaceuticals (San Francisco, CA,USA) [5], contains botulinum toxin type B and is available under the name Neurobloc in Europe. Myobloc functions in a similar manner as the type A botulinum toxin, although the two serotypes are not interchangeable for all uses.Aside from being antigenically distinct serotypes, Myobloc differs from botulinum toxin type B in its formulation characteristics, complications, dosing, and response [5, 6].