Botulinum A exotoxin for glabellar folds: a double-blind, placebo-controlled study with an electromyographic injection technique.

BACKGROUND: Botulinum A exotoxin (BTX) has been used successfully to treat a variety of hyperkinetic movement disorders. BTX is also capable of reducing hyperkinetic facial lines including prominent glabellar frown lines. OBJECTIVE: The purposes of this study were to (1) confirm the efficacy of BTX in a double-blind, placebo-controlled investigation; (2) evaluate the use of an electromyogram attached to the injection needle to confirm intramuscular corrugator placement of the BTX; and (3) determine the optimum direction injection technique. METHODS: Length and depth of glabellar frown lines were measured before treatment and 4 and 12 weeks after injection of 10 units of BTX or saline solution. RESULTS: Patients treated with BTX had a highly significant reduction in depth and length of glabellar frown lines compared with control subjects. CONCLUSION: BTX appears to be effective and safe for reduction of glabellar frown lines.