Olsalazine is a compound consisting of two 5-amino
salicylate (5-ASA) molecules linked by an azo bond, which, administered orally, is split by colonic bacteria to liberate 5-ASA. It lacks the
sulfapyridine moiety found in
sulfasalazine. Using a specific protocol, we conducted a randomized, double-blind, placebo-controlled trial of
olsalazine in patients with symptomatic
ulcerative colitis. Inclusion criteria included mild to moderate disease with involvement of more than 15 cm of colon, visible blood in stools, and the discontinuation of all other medications prior to and during the study. Patients were given oral
olsalazine 3.0 g/day or placebo for 4 wk. Patients were evaluated clinically, by laboratory analysis and by colonoscopic evaluation, at entry and at 4 wk. Additional clinical and laboratory evaluations were performed at 2 wk. Fifteen patients entered the study. Of the seven patients randomized to
olsalazine, four (57%) improved clinically and by colonoscopic scoring, one showed no improvement in either, and two (29%) withdrew after developing severe watery
diarrhea. Of the eight patients treated with placebo, two (25%) improved clinically but were without colonscopic improvement and six (75%) worsened, of whom four withdrew early because of worsening symptoms of
colitis. Seven of eight placebo patients were then treated with
olsalazine on an open basis. Of these seven, five (71%) improved clinically and colonoscopically and two (29%) withdrew because of severe watery
diarrhea. Overall, of 14 patients treated with
Olsalazine, nine (64%) improved, one showed no improvement, and four (29%) discontinued because of persistent watery
diarrhea. No other serious side effects were noted. Minor side effects included transient
diarrhea, flares of
acne, and anxiety attacks which resolved despite continuation of the
drug.