Abstract

Hemifacial spasm (HFS) is a disease causing abnormal movement of the face. Treatment with a botulinum toxin injection is effective. Original botulinum toxin is expensive, particularly in developing countries. We evaluated clinical efficacy and safety of generic botulinum toxin in HFS patients. A 16-week, open labeled, prospective study to evaluate Neuronox^® treatment at HFS clinic, Khon Kaen University hospital, Thailand was carried out. Peak improvement (PI), time to PI (TPI), and duration of response period (D) were reported by patients every 4 weeks. In total, 50 HFS patients participated in the study; 30 new and 20 previously diagnosed patients. Two patients did not response to Neuronox^® treatment; one in each group. For those who responded to Neuronox^® treatment, the mean PI, TPI, and D was 73.44%, 9.44 weeks, and 15 weeks, respectively. The PI, TPI, and D were not statistically different between new and previously diagnosed patients. Ptosis and facial paresis were the common side effects and mostly occurred in the first 4 weeks. Treatment of HFS by generic Neuronox^® botulinum toxin is an effective alternative treatment with similar rate of side effects to original botulinum toxin. It may be preferable in countries with limited healthcare resources.

Key words: Hemifacial spasm, Neuronox^®, botulinum toxin, efficacy, side effects.