Botulinum toxin in the management of blepharospasm: current evidence and recent developments

Abstract

Blepharospasm is a focal dystonia characterized by involuntary closure of the eyelids [Stacy, 2007]. It usually affects both orbicularis oculi, and can progress into causing significant disability. It may occur in isolation, or be associated with other dystonias. Parkinsonism, dystonic cerebral palsy, and tardive phenomena are some of the commonly associated disorders. Adequate treatment of blepharospasm is necessary to allow maintenance of quality of life, avoid functional blindness, and to prevent complications such as corneal abrasions and dermatochalasis. In 1989, blepharospasm (in patients older than 12 years old) was the first indication approved by the United States Food and Drug Administration (FDA) for the use of BoNT-A [Ramirez-Castaneda and Jankovic, 2013]. Before the introduction of chemodenervation through botulinum neurotoxin (BoNT) injections, treatment was challenging, as oral medications had minimal effectiveness and produced limiting side effects. We provide here an up-todate review of the use of BoNT for blepharospasm. Epidemiology Prevalence estimates of blepharospasm range from 16-133 cases per million [Defazio and

A trial of a mechanical device for the treatment of blepharospasm

“…Botulinum toxin injections are the most effective treatment for blepharospasm [10]. These not only reduce the forceful spasms of eye closure by weakening the orbicularis oculi, but also often normalise or reduce the high periodic blink rate and reduce the sensory symptomatology.…”

Pharmacological differences and clinical implications of various botulinum toxin preparations: a critical appraisal

“…The manufacturing processes of BoNTAs, as well as the analytical specifications and methods for assessment of biological activity, are specific for each of the marketed products. Given that the manufacturing process (from the Clostridium strain to purification and biological assessments) is different from one manufacturer to another, the different BoNTA preparations (made using completely different processes) and their doses are not equivalent (Hellman and Torres-Russotto, 2015). Therefore, their benefits, side effects and treatment indications are not interchangeable.…”

Di̇ş Heki̇mli̇ği̇nde Botoks: Derleme

“…Diğer btx-a ürünlerinden daha az immünojeniktir 2 . Ayrıca diğer btx formları dolapta saklanabilirken oda ısısında saklanabilen tek formdur 25 . Prosigne ise piyasada henüz yeni bir üründür ve Botox"la bazı terapotik kullanımlarda benzer özel-liklere sahiptir ancak klinik çalıĢmalara ihtiyaç vardır 26 .…”

“…2001"de, FDA tarafından sadece servikal distoni ve hemifasiyal spazmların tedavisinde kullanım için onaylanmıştır 2 . Göz kapağı düĢüklüğü olan vakalarda, bazı kırıĢıklıklar için ve kozmetik nöroblokaj için btx-a ürünlerine direnci olan hastalarda alternatif olarak kullanılabilir 2,25 . Myobloc flakonlarında dozlar sulandırılmıĢ olarak 25 ng (2500 U)/0.5 cc, 50 ng (5000 U)/1.0 cc, 100 ng (10.000 U)/2.0 cc olacak Ģekilde %0.05 albüminle birlikte bulunur.…”