title: Efficacy and safety of comfrey root extract ointment in the treatment of acute upper or lower back pain: results of a double-blind, randomised, placebo controlled, multicentre trial.
abstract: OBJECTIVE
  The objective was to show the superiority of comfrey root extract ointment to placebo ointment in patients with acute upper or lower back pain.
  
  
  METHODS
  The study was conducted as a double-blind, multicentre, randomised clinical trial with parallel group design over a period of 5 days (SD 1). The patients (n = 120, mean age 36.9 years) were treated with verum or placebo ointment three times a day, 4 g ointment per application. The trial included four visits.
  
  
  METHODS
  The primary efficacy variable was the area under the curve (AUC) of the visual analogue scale (VAS) on active standardised movement values at visits 1 to 4. The secondary efficacy variables were back pain at rest using assessment by the patient on VAS, pressure algometry (pain-time curve; AUC over 5 days), global assessment of efficacy by the patient and the investigator, consumption of analgesic medication and functional impairment measured using the Oswestry disability index.
  
  
  RESULTS
  There was a significant treatment difference between comfrey extract and placebo regarding the primary variable. In the course of the trial the pain intensity on active standardised movement decreased on average (median) approximately 95.2% in the verum group and 37.8% in the placebo group.
  
  
  CONCLUSIONS
  The results of this clinical trial were clear-cut and consistent across all primary and secondary efficacy variables. Comfrey root extract showed a remarkably potent and clinically relevant effect in reducing acute back pain. For the first time a fast-acting effect of the ointment (1 h) was also witnessed.
authors.affiliation: CRM Pharmaberatung GmbH, Rheinbach, Germany.
authors.forename: B M
authors.initials: BM
authors.lastname: Giannetti
authors.forename: C
authors.initials: C
authors.lastname: Staiger
authors.forename: M
authors.initials: M
authors.lastname: Bulitta
authors.forename: H-G
authors.initials: HG
authors.lastname: Predel
mesh_terms: D000208:Acute Disease; D000328:Adult; D020844:Comfrey; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D009824:Ointments; D008517:Phytotherapy / Q000379:methods*; D010936:Plant Extracts / Q000627:therapeutic use*; D018517:Plant Roots; D016896:Treatment Outcome
chemical_list: D009824:Ointments; D010936:Plant Extracts