title: Long-term efficacy of botulinum toxin A in treatment of various movement disorders over a 10-year period.
abstract: Although botulinum toxin A (BTX) has been licensed in Canada for treatment of various movement disorders since 1990, few clinical studies regarding its long-term efficacy and side effects have been reported. We conducted a retrospective analysis of 235 patients who received BTX from our movement disorders clinic over a 10-year period (January 1990 to December 1999). A total of 2,616 treatment cycles (multiple injections) were administered to 235 patients with cervical dystonia (CD), hemifacial spasm (HS), blepharospasm (BP), and other movement disorders. Substantial benefit at 5 years was seen in most patients (90% in BP, 88% in HS, 63% in CD, 100% in jaw closing and lower limb dystonia, and 56% in writer's cramp). Benefit was maintained for up to 10 years in CD, HS, and BP data, with a 75.8% benefit reported. Twenty-eight percent of patients discontinued treatment during the follow-up period due to a variety of reasons. Of these, 9.1% of patients developed primary resistance, and 7.5% of patients secondary resistance. Adverse effects, mostly minor, developed in 27% of patients at any one time, occurring over 4.5% of treatment cycles. These were most frequently reported in blepharospasm (22 of 36 patients in 40 cycles), followed by hemifacial spasm (21 of 70 patients in 46 cycles), and cervical dystonia (17 of 106 in 28 cycles). Only 1.3% of patients discontinued therapy due intolerable adverse effects. The results show that BTX is a safe and effective treatment of various types of movement disorders, and most side effects are well tolerated. Discontinuation for any reason was also low after 5 years. Efficacy was maintained after long periods of treatment with high degree of patient satisfaction.
authors.affiliation: Movement Disorders Clinic, Department of Clinical Neurosciences at University of Calgary, Alberta, Canada.
authors.forename: G-Y R
authors.initials: GY
authors.lastname: Hsiung
authors.forename: S K
authors.initials: SK
authors.lastname: Das
authors.forename: R
authors.initials: R
authors.lastname: Ranawaya
authors.forename: A-L
authors.initials: AL
authors.lastname: Lafontaine
authors.forename: O
authors.initials: O
authors.lastname: Suchowersky
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019274:Botulinum Toxins, Type A / Q000008:administration & dosage* / Q000009:adverse effects; D001955:British Columbia; D004305:Dose-Response Relationship, Drug; D004351:Drug Resistance; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007273:Injections, Intramuscular; D008134:Long-Term Care; D008297:Male; D008875:Middle Aged; D009069:Movement Disorders / Q000188:drug therapy* / Q000209:etiology; D017060:Patient Satisfaction; D012189:Retrospective Studies; D016896:Treatment Outcome
chemical_list: D019274:Botulinum Toxins, Type A