Authors: Alice Weatherston
In a presentation that took place yesterday at the American Academy of Neurology (AAN) 68th Annual Meeting (15 – 21st April, Vancouver, BC, Canada) new AAN guidelines for the use of botulinum toxin for spasticity, cervical dystonia, blepharospasm and migraine were released based on recent updates in research.
Currently four noninterchangeable preparations of botulinum toxin are available in the USA – the new guideline assessed each of these formulations separately for each of the identified conditions.
A research team reviewed all available literature on the use of botulinum toxin in the disorders, concluding that the drug is generally safe and effective for treating adult spasticity, cervical dystonia, blepharospasm and chronic migraine.
Major changes from the previous guidelines consist of its use in the treatment of chronic migraine, which was not previously recommended, due to a lack of supportive scientific evidence. Studies, particularly with onabotulinumtoxinA, have now indicated reductions in the regularity of headaches with the drug, however these benefits are currently still small. Individuals treated generally exhibit a reduction of around 15% in the number of days suffering with a headache four weeks after initial treatment, in comparison to a placebo.
No updates were made to guidelines for essential tremor, hemifacial spasm and disorders of the voice due to no new scientific evidence being available since the 2008 guideline publication.
AbobotulinumtoxinA, incobotulinumtoxinA, and onabotulinumtoxinA are recommended for spasticity and rimabotulinumtoxinB should be considered. For lower limb spasticity specifically abobotulinumtoxinA and onabotulinumtoxinA are recommended.
Cervical dystonia is responsive to abobotulinumtoxinA and rimabotulinumtoxinB and the use of onabotulinumtoxinA and incobotulinumtoxinA should be considered for treatment.
Finally, the guidelines for blepharospasm state that onabotulinumtoxinA and incobotulinumtoxinA are probably effective and should be considered and that abobotulinumtoxinA is possibly effective and may be considered.