Proof of Concept, Feasibility, and Safety of Local Anticholinesterase Treatment for Neuromodulator-Induced Facial Muscle Paralysis.

[BACKGROUND] As yet, there is no functional focal reverser for the adverse effects of cosmetic botulinum toxin injections.

[OBJECTIVE] The authors report the first Phase 1 study in human subjects of local administration of an anticholinesterase for reversing muscle weakness, which may result from these neurotoxin-induced complications.

[MATERIALS AND METHODS] An anticholinesterase, or cholinesterase inhibitor, indicated for reversal of neuromuscular blockage in anesthesia, was injected into the same 5 injection sites as were used for the cosmetic onabotulinum toxinA, glabellar treatment.

[RESULTS] In most patients treated with the reversal agent under investigation, there was a notable recovery of cosmetic blockade; no subject treated with placebo demonstrated a reversal response. Evidence of reversal became evident within the first 15 minutes after injection of the study drug, with no major or persistent adverse events.

[CONCLUSION] Proof of concept, feasibility, and safety of local neuromodulator reversal are now shown; however, further studies are required to optimize dosage, distribution, and formulation.