Adverse reactions to botulinum toxin (Botox®, Dysport®, Vistabel®, Neurobloc®)

In cooperation with the European Pharmacovigilance Working Party, the Danish Medicines Agency has studied adverse reactions to medicinal products containing botulinum toxin. Botulinum toxin is licensed for the treatment of different types of muscle spasms, but it is also used cosmetically to smooth skin wrinkles.

In very rare cases, serious adverse events have been identified as a result of the botulinum toxin having spread to adjacent muscles. Reports point to muscular weakness and difficulties in swallowing and breathing. Swallowing difficulties increase the risk of food entering the respiratory tract and lungs.

The Danish Medicines Agency has received nine reports on such adverse reactions. Worldwide, more than 600 serious adverse reactions have been recorded.

Compared with the overall consumption, these adverse reactions are rare. However, it is important to stress that only doctors specialised in this type of treatment should give botulinum toxin. Furthermore, doctors must be aware that some patients, e.g. patients with neurological disorders, may be more exposed to adverse reactions.

Companies that market products with botulinum toxin have been ordered to inform doctors about the adverse reactions observed. Furthermore, the Danish Medicines Agency emphasises to doctors the importance of following the dose guidance.

The Danish Medicines Agency advises doctors and patients who experience adverse reactions to report such reactions. See the factbox to the right if you want to report adverse reactions.

For further information, please contact Chief Medical Officer Doris Irene Stenver, Consumer Safety Division, telephone +45 44 88 92 47.