What is a Botox Injection Anyway?

The cosmetic form of botulinum toxin, often referreddrug for the treatment of strabismus, hemifacial
to by its product name Botox, is a popularspasms, and blepharospasm. BOTOX is distributed in
non-surgical injection that temporarily reduces or100-unit vials.The original batch of neurotoxin
eliminates frown lines, forehead creases, crows feetprepared by Shantz in November 1979 (designated
near the eyes and thick bands in the neck. The toxinbatch 79-11) constituted the original BOTOX
blocks the nerve impulses, temporarily paralyzing theformulation and was used until December 1997. It
muscles that cause wrinkles while giving the skin awas replaced by a new neurotoxin complex batch
smoother, more refreshed appearance. Studies havedesignated BCB 2024. The new bulk batch is 5-6
also suggested that Botox is effective in relievingtimes more potent on a weight basis. In a 100-unit
migraine headaches, excessive sweating and musclevial, only 4.8 ng of neurotoxin is needed compared to
spasms in the neck and eyes. Botulinum neurotoxin is25 ng of 79-11. The new BOTOX is comparable in
produced by the gram-negative anaerobic bacteriumclinical efficacy and safety to the old, and a unit dose
Clostridium botulinum.of new BOTOX provides an equivalent response to
Eight serologically distinct botulinum neurotoxins exist,the same unit dose of old BOTOX. Hopefully, the
designated as A, B, C1, C2, D, E, F, and G. Seven arereduced protein load of the new BOTOX leads to
associated with paralysis. Types A, B, E and, rarely, Freduced immunogenicity and a lower incidence of
and G are associated with human botulism.The doseneutralizing antibody formation.Dysport is another
of botulinum toxin is expressed in mouse units. Oneformulation of botulinum toxin type A available in
unit is equal to the amount that will kill 50% of aEurope and a few other countries. It is prepared
group of 18- to 22-g Swiss Webster mice whenusing column-based purification techniques and
injected intraperitoneally. The human lethal dose (LD)distributed in 500-unit vials that can be stored at
for BOTOX (botulinum type A purified neurotoxinroom temperature. BOTOX and Dysport are both
complex) is estimated at approximately 3000 units.botulinum toxin type A preparations but are quite
BOTOX injections of less than 100 units usually aredistinct from one another. BOTOX is approximately 4
used for cosmetic purposes and of less than 300-600times more potent on a per unit basis, and Dysport
units for other purposes, thereby allowing a widedoses often are approximately 4 times the BOTOX
safety margin. Recognizing that doses are notdoses used to generate a similar clinical effect.
interchangeable among different formulations ofDifferences in these toxins may relate to differences
botulinum toxin (BOTOX, Dysport, Myobloc) isin the strain of bacterium, preparation, diffusion, and
important; to achieve similar clinical effects, differentpotency testing.Myobloc is a botulinum toxin type B
doses are used.BOTOX is a sterile lyophilized form ofpreparation currently in clinical trials. It is anticipated
botulinum toxin type A. It is produced from a culturethat it will be distributed as a solution. Little
of the Hall strain of C botulinum and purified by ainformation is available concerning the cosmetic use
series of acid precipitations to a crystalline complexof Dysport and Myobloc. The remainder of this article
containing the toxin and other proteins. The FDAtherefore focuses on BOTOX, and all unit doses
approved BOTOX in December 1989 as an orphanrefer to BOTOX unless otherwise specified.