title: Topical L-arginine gel lowers resting anal pressure: possible treatment for anal fissure.
abstract: OBJECTIVE
  Exogenous nitric oxide donors, such as glyceryl trinitrate, have been used as treatment for anal fissures; however, headaches develop in 60 percent of patients. Nitric oxide produced from the cellular metabolism of L-arginine mediates relaxation of the internal anal sphincter. This study investigated whether topical L-arginine gel reduces maximum anal resting pressure in volunteers.
  
  
  METHODS
  In a two-center study, volunteers received a single topical dose of L-arginine or placebo (Aquagel ). Anal manometry was performed for two hours after application of 400 mg of L-arginine gel or placebo gel to the anal verge in 25 volunteers. Side effects were recorded after single application and also after repeated dosing for three days.
  
  
  RESULTS
  L-Arginine reduced maximum anal resting pressure by 46 percent from a median of 65 cm of water to a minimal value of 35 cm of water ( P< 0.001, Wilcoxon's signed-rank test). The difference between L-arginine and placebo using repeated-measures testing was significant at P< 0.005. No side effects occurred with either gel; in particular, no episodes of headache were recorded.
  
  
  CONCLUSIONS
  Topical L-arginine gel significantly lowers maximum anal resting pressure; its onset of action is rapid, and duration is at least two hours ( P< 0.01). L-arginine may have therapeutic potential, but further evaluation is needed before it can be used as a possible alternative treatment for chronic anal fissure.
authors.affiliation: Department of Surgery, Queen's Medical Centre, Nottingham, United Kingdom.
authors.forename: N
authors.initials: N
authors.lastname: Griffin
authors.forename: D D E
authors.initials: DD
authors.lastname: Zimmerman
authors.forename: J W
authors.initials: JW
authors.lastname: Briel
authors.forename: H-J
authors.initials: HJ
authors.lastname: Gruss
authors.forename: M
authors.initials: M
authors.lastname: Jonas
authors.forename: A G
authors.initials: AG
authors.lastname: Acheson
authors.forename: K
authors.initials: K
authors.lastname: Neal
authors.forename: J H
authors.initials: JH
authors.lastname: Scholefield
authors.forename: W R
authors.initials: WR
authors.lastname: Schouten
mesh_terms: D000287:Administration, Topical; D000328:Adult; D001003:Anal Canal / Q000187:drug effects*; D001120:Arginine / Q000008:administration & dosage*; D005260:Female; D005401:Fissure in Ano / Q000188:drug therapy*; D005782:Gels; D006801:Humans; D008297:Male; D008365:Manometry; D008875:Middle Aged; D011312:Pressure; D016037:Single-Blind Method
chemical_list: D005782:Gels; D001120:Arginine