Volume No 33 Issue No 2

Does Prolonged Botulinum Toxin A Treatment Decrease its Duration of Action?

Purpose: To find out the results of prolonged Botulinum toxin A on its duration of action in patients with blepharospasm and hemifacial spasm. Study Design: Prospective Case series. Place and Duration of Study: Yaqin Vision center from 2010 to Dec 2016. Material and Methods: All patients of both genders who were treated with Botulinum toxin for treatment of hemifacial spasm and blepharospasm were included in the study. Patients were divided into 2 groups, Group 1 included all patients who had 2-5 injection while group 2 included all patients who had 5-19 injections of botulinum toxin A. Patients with secondary blepharospasm due to drugs, ocular and neurological disorders were excluded from the study. Patients with blpharospasm were injected botulinum toxin A at 7 periocular sites on both sides while patients with hemifacial spasm were injected at 7 periocular and 6-7 perioral sites (orbicularis oris, levator labi, zygomaticus major, mentalis and platysma). Onset of effect of botulinum toxin A and duration of action was recorded for all patients. Results: Total 257 injections were given to 40 patients with an average of 6.43 injections (range 2-19). The mean age of patients was 51 12.1 years. Male to female ratio was 1:1.1. Mean onset of action in Group 1 was 3.81 2.6 days and in Group 2 was 3.92 3.4 days after injection. Average 51.13 units of botulinum toxin A were injected in each injection. Mean duration of botulinum toxin A efficacy in Group 1 was 3.43 1.5 months and in Group 2 was 3.26 1.6 months. Non-significant p-values of 0.41 for onset and 0.23 for duration were found. Conclusion: After prolong use of botulinum injection mean duration of action remains almost same. Keywords: Blepharospasm, Hemifacial spasm, Botulinum toxin

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