Complications of botulinum toxin type A.

Introduced over 30 years ago for the treatment of strabismus and blepharospasm, botulinum toxin type A (BTX-A) now has established uses for various therapeutic and cosmetic purposes. Although remarkably safe and effective, BTX-A is a potent toxin. Complications can occur, particularly when used by the inexperienced injectors. Through knowledge of its mechanism of action and effect and careful attention to dosing and technique can minimize the risk of more serious adverse events.