Abstract
Botulinum toxin (BoTX) is the strongest known poison, but also one of the most diverse drugs with many therapeutic opportunities. It selectively inhibits acetylcholin (ACH) at the cholinergic synapses and can thus be used as a blockade for nerve impulses.
Striated and smooth muscles as well such as welding, salivary and lacrimal glands are stimulated by cholinergic synapses, who can be inhibited irreversibly by BoTX until new nerve endings are built again. Although potential therapeutic use of the toxin has been suggested already in the 19th century, it took nearly 150 years before A.
Scott, an ophthalmologist from San Francisco (USA), evaluated the effect on the eye muscles in rabbits. Finally, this resulted in the first therapeutic use in the treatment of strabismus.
Since then, several indications for BoTX have been established such as torticollis, blepharospasmus or hemifascial spasm. Today, the range of indications is growing in various medical specialties.
Besides this effect on muscular action, the effectiveness of BoTX in chronic pain indications has been evaluated in several clinical pilot trials. Although being an off label use, indications such as chronic tennis elbow, plantar fasciitis or chronic myofascial neck and shoulder pain have been evaluated with positive clinical outcome.
Whereas the effect of BoTX and its mechanism of action is clear with regards to the weakening of muscular strength and the effect on glands, its possible effect within the peripheral pain sensation remains unclear.