title: Two doses of botulinum toxin type A for the treatment of trigeminal neuralgia: observation of therapeutic effect from a randomized, double-blind, placebo-controlled trial.
abstract: BACKGROUND
  In the majority of cases, trigeminal neuralgia (TN) is a unilateral condition with ultra-short stabbing pain located along one or more branches of the trigeminal nerve. Although prophylactic pharmacological treatment is first choise, considering of insufficient effect or unacceptable side effects, neurosurgical treatment or lesion treatment should be considered. In addition to all these procedures mentioned above, one approach has been based on local intradermal and/or submucosal injections of Botulinum Toxin Type A (BTX-A).
  
  
  METHODS
  We conducted a randomized, double-blind, placebo-controlled since November 2012, and adopted local multi-point injection in 84 cases of classical TN with different doses of BTX-A. Eighty four patients were randomized into following groups: placebo (n = 28); BTX-A 25U (n = 27); BTX-A 75U (n = 29). Follow-up visits were conducted every week after the injection, and the overall duration of the study for each patient were 8 weeks to observe the pain severity, efficacy and adverse reactions at endpoint.
  
  
  RESULTS
  The visual analogue scale (VAS) scores of 25U and 75U groups reduced significantly compared to placebo as early as week 1, and sustained until week 8 throughout the study. There was no significant difference in VAS between 25U and 75U groups throughout the study. The response rates of 25U group (70.4%) and 75U group (86.2%) were significantly higher than placebo group (32.1%) at week 8, and there was no significant difference between 25U and 75U groups. Evaluation of the Patient Global Impression of Change (PGIC) demonstrated that 66.7% (25U group) and 75.9% (75U group) of the patients reported that their pain symptoms were 'much improved' or 'very much improved' versus 32.1% of the placebo group, and there was also no significant difference between 25U and 75U groups. All adverse reactions were graded as mild or moderate.
  
  
  CONCLUSIONS
  BTX-A injection in TN is safe and efficient. It is a useful treatment for refractory TN. Lower dose (25U) and high dose (75U) were similar in efficacy in short-term.
authors.forename: Haifeng
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Neurology, the First Affiliated Hospital, Zhengzhou University, 1 Jianshe East R, Zhengzhou City, HeNan Province 450052, People's Republic of China. lianyajun840317@163.com.
authors.forename: Yajun
authors.initials: Y
authors.lastname: Lian
authors.forename: Yunqing
authors.initials: Y
authors.lastname: Ma
authors.forename: Yuan
authors.initials: Y
authors.lastname: Chen
authors.forename: Caihong
authors.initials: C
authors.lastname: He
authors.forename: Nanchang
authors.initials: N
authors.lastname: Xie
authors.forename: Chuanjie
authors.initials: C
authors.lastname: Wu
mesh_terms: D000368:Aged; D019274:Botulinum Toxins, Type A / Q000008:administration & dosage* / Q000009:adverse effects / Q000494:pharmacology; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009465:Neuromuscular Agents / Q000008:administration & dosage* / Q000009:adverse effects / Q000494:pharmacology; D010147:Pain Measurement; D016896:Treatment Outcome; D014277:Trigeminal Neuralgia / Q000188:drug therapy*
chemical_list: D009465:Neuromuscular Agents; D019274:Botulinum Toxins, Type A