The use of botulinum toxin in physical medicine and rehabilitation.

A review of the history and pharmacology of the botulinum neurotoxins is presented. Established mechanisms of action are discussed as well as preliminary evidence of other potential mechanisms, as related to botulinum toxins' antinociceptive properties. Methods of administration, including reconstitution, dilution, and basic injection techniques/principles are reviewed. Safety concerns are also addressed. Various applications relevant to the field of Physical Medicine & Rehabilitation are reviewed, specifically uses in the management of muscle over activity syndromes such as upper motor neuron-related spasticity, dystonias, and painful syndromes including Myofascial Pain Syndromes and headaches. Relevant literature related to these applications is reviewed and discussed. Botulinum toxin therapeutic efficacy and possible reasons for treatment failure (including development of antibody-mediated resistance) are discussed.