Effect of Olsalazine and Mesalazine on Intraluminal pH of the Duodenum and Proximal Jejunum in Healthy Humans

Abstract

Fallingborg J, Christensen LA. Jacobsen BA, Ingeman-Nielsen M, Rasmussen HH, Abildgaard K, Rasmussen SN. Effect of olsalazine and mesalazine on intraluminal pH of the duodenum and proximal jejunum in healthy humans. Scand J Gastroenterol 1994;29:498-500.

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, radio-transmitting 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.

Key Words:

• Duodenum
• Jejunum
• Mesalazine
• Olsalazine
• pH