title: Alpha-1 adrenoceptor blockade: potential new treatment for anal fissures.
abstract: OBJECTIVE
  Patients with chronic anal fissures are known to have high resting anal pressures that return to normal after successful surgical treatment. Internal anal sphincter activity is increased by sympathetic excitatory innervation via alpha adrenoceptors. The objective of this study was to determine the effect of alpha-1 adrenoceptor blockade on anal sphincter pressure in patients with and without chronic anal fissures.
  
  
  METHODS
  The effect on the anal canal pressure profile of a single oral 20 mg dose of indoramin, an alpha-1 adrenoceptor antagonist, on seven patients with chronic anal fissure and six healthy patients without a fissure was investigated.
  
  
  RESULTS
  Indoramin reduced anal resting pressures in those with anal fissure by a mean of 35.8 percent, from 106.9 +/- 22.15 cm H2O to 68.6 +/- 20.35 cm H2O, and in those without anal fissure by a mean of 39.9 percent, from 84.17 +/- 27.46 cm H2O to 52.17 +/- 24.78 cm H2O, after one hour. This pressure reduction persisted at three hours, and its magnitude is comparable to that obtained after internal sphincterotomy. The pressure reduction occurred over the whole length of the anal canal.
  
  
  CONCLUSIONS
  It is proposed that alpha-1 adrenoceptor antagonists could be a suitable treatment for chronic anal fissure and other painful conditions where reduction in anal pressure is warranted.
authors.affiliation: University College London Medical School, United Kingdom.
authors.forename: J
authors.initials: J
authors.lastname: Pitt
authors.forename: M M
authors.initials: MM
authors.lastname: Craggs
authors.forename: M M
authors.initials: MM
authors.lastname: Henry
authors.forename: P B
authors.initials: PB
authors.lastname: Boulos
mesh_terms: D000317:Adrenergic alpha-Antagonists / Q000627:therapeutic use*; D000328:Adult; D002908:Chronic Disease; D005260:Female; D005401:Fissure in Ano / Q000188:drug therapy*; D006801:Humans; D007217:Indoramin / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D016896:Treatment Outcome
chemical_list: D000317:Adrenergic alpha-Antagonists; D007217:Indoramin