Botex, or Botulinum toxin, has raised safety concern and made the Food and Drug Administration conduct a review of the product. The trigger was the reports of deaths and breathing problems in some patients.
The dead list contains only children being treated for cerebral palsy-associated limb spasticity. The product is not approved and allowed for such use. But still there is no evidence that deaths were caused by any overdose or defect in the product.
Botex is a brand name for one of the most toxic proteins, used in minute doses both to treat painful muscle spasms, and as a cosmetic treatment in some parts of the world.
The similar toxin under investigation is Myobloc. It is manufactured by Solstice Neurosciences Inc., a private firm based in Malvern, Pa. It is used for blocking nerve impulses to certain muscles, causing them to relax, and is approved to treat cervical dystonia.
Side effects of both products can be predicted from the mode of action (muscle paralysis) and chemical structure (protein) of the molecule, resulting broadly speaking in two major areas of side effects: paralysis of the wrong muscle group and allergic reaction. Bruising at the site of injection is a side effect not of the toxin, but rather the mode of administration.
They may cause respiratory failure due to paralysis of the respiratory muscles, and in some cases cause difficulty swallowing, dysphagia.