Colonic Prostaglandin E₂ Levels and Olsalazine Metabolism in Relapsing Ulcerative Colitis: Implications for Controlled Trials in the Long Term

Abstract

To examine the tolerance and pharmacokinetics of long-term olsalazine administration, increasing doses of the drug were given to 31 patients with ulcerative colitis. All patients were refractory to or intolerant of sulphasalazine. Complete azo-reduction occurred in most cases. Concentrations of 5-ASA, but not acetyl-5-ASA, in faecal dialysates increased dose-dependently. Estimates of efficacy were more favourable among those intolerant of sulphasalazine. Patients with high prostaglandin E₂ levels determined by equilibrium in vivo dialysis of rectum were less likely to benefit from treatment. In conclusion, olsalazine is a highly effective means of delivering 5-ASA to the colonic mucosa. Long-term use of olsalazine in controlled trials may be considered safe, even in high doses.

Key Words:

• Olsalazine
• pharmacokinetics
• prostaglandin E₂
• sulphasalazine intolerance
• ulcerative colitis