Botulinum toxin products: rare but serious risks

Products that contain botulinum toxin are associated with the risk of serious adverse reactions due to distant spread of toxin.

Article date: October 2007

4 products that contain botulinum toxin that are licensed in the UK include:

  • botox
  • dysport
  • neuroBloc
  • vistabel.

Indications include focal spasticity, some types of spasm, and excessive sweating of the axillae (arm pits). Vistabel is indicated only for treatment of vertical frown lines between the eyebrows, where their severity has an important psychological effect on the patient. Botulinum toxins prevent the release of acetylcholine at neuromuscular or other cholinergic junctions and reversibly denervate muscles or eccrine glands.

Other reactions can include:

  • spread reactions including muscle weakness, dysphagia, and aspiration - these have been reported rarely with all products that contain botulinum toxin
  • extreme caution is needed on administration of products that contain botulinum toxin to patients who have neurological disorders, or a history of dysphagia or aspiration
  • only physicians with appropriate experience (including use of the required equipment) should administer products that contain botulinum toxin
  • patients or caregivers should be informed about the risk of spread of toxin, and should be advised to seek immediate medical care if problems with swallowing or speech develop, or if respiratory symptoms arise
  • units of botulinum toxin are not interchangeable from one product to another
  • recommended administration techniques and specific dosing guidance (including the recommendation to use the minimum effective dose and titrate according to individual need) should be followed

For more information see letters sent to healthcare professionals in June 2007.


Article citation: Drug Safety Update October 2007; Vol 1, Issue 3: 10.

Updates to this page

Published 11 December 2014