Current and investigated alternatives to botulinum toxin for managing blepharospasm

Introduction: Benign essential blepharospasm (BEB) is an adult-onset focal dystonia characterized by involuntary spasms of the orbicularis oculi (OO) muscle. BEB typically develops in the fifth to sixth decade, has a variable female preponderance, and a tendency to spread to adjacent body regions. Idiopathic BEB is thought to be a multifactorial disorder resulting from the contribution of both environmental and genetic factors. To date, BEB treat- ment is largely based on botulinum A toxin (BTX). Areas covered: This article summarizes current knowledge on the therapeutic approaches that can be proposed to BEB patients who are truly unresponsive to BTX. Current and investigated alternatives to BTX can be included in the following categories: i) alternative therapeutic weakening of the OO muscle; ii) treatments of ophtalmological complaints; and iii) therapeutic interven- tions on central nervous system mechanisms underlying BEB. Expert opinion: Therapeutic strategies to manage BEB of patients who are truly unresponsive to BTX are very limited. Currently available treatments include myectomy, oral medication and deep brain stimulation. Experimental therapeutics include topical acetyl hexapeptide-8, a promising new drug for extending the duration of action of BTX, and transcranial magnetic stimula- tion. At present, the choice of the best treatment strategy, including medical, surgical and non-invasive treatments remains largely empirical and depend- ing on existing reports of toxicity rather than efficacy.