title: Effect of olsalazine and mesalazine on intraluminal pH of the duodenum and proximal jejunum in healthy humans.
abstract: BACKGROUND
  Treatment of inflammatory bowel disease with olsalazine causes diarrhoea in 10% of patients. This is claimed to be caused by a drug effect on mucosal transport in the small intestine, which might be reflected in the intraluminal pH. We aimed to study the effect on jejunal pH of olsalazine (Dipentum) and an alternative preparation, slow-release mesalazine (Pentasa).
  
  
  METHODS
  Thirteen healthy volunteers, seven male and six female, participated in a randomized, crossover study. Steady-state conditions were obtained after ingestion of 2 g or 6 g mesalazine daily or 2 g olsalazine daily for 1 week. The pH of the duodenum and proximal jejunum was measured by using pH-sensitive, radiotransmitting capsules, the location of which was confirmed by fluoroscopy.
  
  
  RESULTS
  No effect of either drug on duodenal pH was detected. Mean duodenal pH ranged from 6.18 to 6.22. The mean pH of the pre-medication proximal jejunum was 6.02. Mesalazine had no significant effect, but olsalazine significantly increased the pH of the proximal jejunum (mean pH, 6.47).
  
  
  CONCLUSIONS
  Our results indicate that the effect of olsalazine on jejunal transport of electrolytes and water, observed in experimental studies, also applies to human subjects in steady-state conditions, and adaptation does not occur within 6 days.
authors.affiliation: Dept. of Medical Gastroenterology, Aalborg Hospital, Denmark.
authors.forename: J
authors.initials: J
authors.lastname: Fallingborg
authors.forename: L A
authors.initials: LA
authors.lastname: Christensen
authors.forename: B A
authors.initials: BA
authors.lastname: Jacobsen
authors.forename: M
authors.initials: M
authors.lastname: Ingeman-Nielsen
authors.forename: H H
authors.initials: HH
authors.lastname: Rasmussen
authors.forename: K
authors.initials: K
authors.lastname: Abildgaard
authors.forename: S N
authors.initials: SN
authors.lastname: Rasmussen
mesh_terms: D000293:Adolescent; D000328:Adult; D000636:Aminosalicylic Acids / Q000494:pharmacology*; D004386:Duodenum / Q000187:drug effects* / Q000378:metabolism*; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007583:Jejunum / Q000187:drug effects* / Q000378:metabolism*; D008297:Male; D019804:Mesalamine
chemical_list: D000636:Aminosalicylic Acids; D019804:Mesalamine; C032587:olsalazine