Treating inflammatory bowel disease during pregnancy: risks and safety of drug therapy

The safety of drug therapy for inflammatory bowel disease during pregnancy is an important clinical concern. Current available information is largely derived from animal studies and clinical experience among patients with inflammatory bowel disease and autoimmune disorders and organ transplant recipients. However, these data are confounded by various factors including difficulty projecting the results of animal studies to humans, methodological deficiencies of some studies, insufficient experience with certain agents, difficulty distinguishing the fetal effects of underlying disease from drug therapy and a need to consider the impact of background rates of adverse fetal outcomes which apply to all pregnancies. In inflammatory bowel disease, the effects of active inflammation on the fetus are believed to be more harmful than those of drug treatment, and therapy is often justified to induce or maintain remission during pregnancy. The choice of appropriate treatment is determined by the severity of the disease and the potential for drug toxicity. No causal relationship has been established between exposure to sulfasalazine or other 5-aminosalicylic acid drugs and the development of congenital malformations. These drugs may be used with relative safety during pregnancy and lactation. Considerable experience with corticosteroids have shown them to pose very small risk to the developing fetus. Current evidence indicates that maternal use of azathioprine is not associated with an increased risk of congenital malformations, though impaired fetal immunity, growth retardation or prematurity is occasionally observed. Preliminary evidence derived from patients with inflammatory bowel disease show no significant fetal toxicity following first trimester exposure to mercaptopurine, though its elective use in pregnancy is controversial. Cyclosporin is not teratogenic, but may be associated with growth retardation and prematurity. Pregnancy should be avoided in women treated with methotrexate because of its known abortifacient effects and risk of causing typical malformations. Although treatment with metronidazole or ciprofloxacin for short durations appear to be devoid of adverse fetal reactions, the effect of prolonged exposure as required in Crohn's disease remains unknown.

Systemic levels of free 5-aminosalicylic acid depend on the nature of the 5-aminosalicyclic acid derivative and not on disease activity or extent in patients with inflammatory bowel disease

INTRODUCTION

Several new derivatives of sulphasalazine that make use of its active moiety, 5-aminosalicylic acid (5-ASA), have been introduced for the treatment of inflammatory bowel disease (IBD). In rats short term intravenous administration of 5-ASA has been associated with nephrotoxicity. A number of cases of nephrotoxicity have been reported recently in IBD patients taking oral maintenance treatment with 5-ASA compounds.

OBJECTIVE

To study the urinary and serum levels of acetylated 5-ASA (Ac-5-ASA) and the unacetylated 5-ASA (5-ASA) in patients with IBD maintained on sulphasalazine, olsalazine and mesalazine (pH dependent release form). We also sought correlation between levels of 5-ASA, clinical disease activity and extent of disease.

METHODS

We studied 79 patients (male, n = 30; female, n = 49) with established IBD [ulcerative colitis (UC), n = 48; Crohn's disease (CD), n = 31], 72 maintained on 5-ASA compounds (sulphasalazine = 27; olsalazine = 28; mesalazine = 17) and 7 patients were receiving no medication. Urinary and serum analysis of 5-ASA was performed by high performance liquid chromatography (HPLC). Clinical disease activity was quantified using simple index of Harvey and Bradshaw.

RESULTS

Patients receiving mesalazine had significantly higher levels of serum free 5-ASA compared to those who were receiving olsalazine and sulphasalazine (mesalazine mean +/- SEM; range; 2.84 +/- 1.21 (0.00-16.00) vs olsalazine 0.45 +/- 0.18 (0.00-16.20); mumol/L; p < 0.04; sulphasalazine 0.37 +/- 0.25 (0.00-3.74); p < 0.03). Similarly levels of urinary free 5-ASA were significantly higher in patients maintained on mesalazine compared to those on olsalazine or sulphasalazine (mesalazine 219 +/- 80.43 (0.00-1050) vs olsalazine 33.3 +/- 17.23 (0.00-317) mumol/L; p < 0.01; and sulphasalazine 15 +/- 8.86 (0.00-192); p < 0.05). However, no significant difference was observed in the levels of urinary free 5-ASA between olsalazine and sulphasalazine. No significant difference was observed in the levels of free-5-ASA in UC patients with left sided disease and those with extensive disease. Furthermore, no significant difference was observed in the levels of serum and urinary 5-ASA in CD patients with ileo-colic disease and colonic disease. Urinary and serum free-5-ASA did not correlate with the clinical disease activity.

CONCLUSION

Systemic absorption of 5-ASA from sulphasalazine and olsalazine is relatively low. However, pH-dependent mesalazine formulations may release their contents rapidly in the small intestine and proximal colon resulting in higher plasma and urinary concentrations of free 5-ASA. The effects of free 5-ASA on renal function in the human require further evaluation.

[Pregnancy outcome in inflammatory bowel diseases]

OBJECTIVE

To assess pregnancy outcome in relation to disease activity and maintenance therapy in patients with inflammatory bowel disease.

METHODS

A postal questionnaire was sent to every woman of child-bearing age followed for inflammatory bowel disease in three referral centers (Rothschild, Saint-Lazare, Saint-Louis). Response rate was 65%.

RESULTS

One hundred and forty-four pregnancies (153 fetuses) in 138 women (122 had Crohn's disease) were reported. Outcome of pregnancy was normal (baby > 2500 g, without malformation) in 115 cases (77%). There were 17 cases of preterm birth (11.5%), 3 cases of hypotrophy, and 14 pregnancy losses (9 miscarriages (6%), 4 therapeutic abortions for major malformation (2.8%)). Percentages of normal pregnancy outcome were not different between patients who continued maintenance therapy and those who stopped: respective percentages were 75 vs 73% in patients receiving mesalamine or olsalazine (n = 30), and 60 vs 75% in patients receiving azathioprine (n = 22).

CONCLUSION

In a selected series of women with inflammatory bowel disease, pregnancy outcome is approaching that observed in a normal population, except for an elevated rate of preterm births. There is no need to stop maintenance therapy with 5-aminosalicylates or azathioprine during pregnancy.

The systemic load and efficient delivery of active 5-aminosalicylic acid in patients with ulcerative colitis on treatment with olsalazine or mesalazine

BACKGROUND

There have been reports of nephrotoxic reactions in patients with ulcerative colitis treated with 5-aminosalicylic acid (5-ASA) preparations.

AIM

To compare the efficacy in delivery of active 5-ASA to the colon and the systemic load as the basis for potential long-term toxicity during treatment with olsalazine or mesalazine in patients with ulcerative colitis in remission.

PATIENTS AND METHODS

Fifteen patients with ulcerative colitis were treated with olsalazine or mesalazine, each for 7 days in an open, randomized, crossover design study. 5-ASA and acetyl-5-ASA (Ac-5-ASA) in plasma and urine were measured by high performance liquid chromatography.

RESULTS

The plasma concentration of 5-ASA was 1.2 +/- 0.1 micromol/L (mean +/- S.E.M.) for olsalazine and 8.0 +/- 1.9 micromol/L for mesalazine, while the plasma concentration of Ac-5-ASA was 2.8 +/- 0.2 micromol/L for olsalazine and 10.8 +/- 1.6 micromol/L for mesalazine. The amount of 5-ASA excreted in the urine was 68 +/- 30 micromol/24 h for olsalazine and 593 +/- 164 micromol/24 h for mesalazine. The amount of Ac-5-ASA in the urine was 1260 +/- 102 micromol/24 h for olsalazine and 3223 +/- 229 micromol/24 h for mesalazine. The urinary recovery of total 5-ASA plus Ac-5-ASA (as a percentage of the given dose) was 23 +/- 2.1% for olsalazine and 39 +/- 3.6% for mesalazine. The ratio between the plasma concentrations of mesalazine and olsalazine differed significantly both for 5-ASA (5.1) and Ac-5-ASA (3.6); for 5-ASA (9. 9) and Ac-5-ASA (2.6) in urine, and for the urinary recovery of total 5-ASA plus Ac-5-ASA (1.7). Moreover, in the mesalazine group there was a large variation in the individual plasma concentrations of 5-ASA and Ac-5-ASA, with maximal values 5-6-fold higher than that in the olsalazine group.

CONCLUSION

The systemic load of active 5-ASA is significantly higher for mesalazine than for olsalazine, when based on the dosages given and when calculated on an equimolar basis. Some of the patients in the mesalazine group showed unexpected high levels of plasma and urinary 5-ASA concentrations, a finding which may have long-term safety implications.

[Acute pancreatitis induced by drugs derived from 5-aminosalicylic acid: case report and review of the literature]

The pancreatic toxicity of oral 5-aminosalicylic acid (5ASA) derivatives used for the treatment of inflammatory bowel diseases remains controversial. A new case of mesalazine-induced acute pancreatitis (AP), with positive rechallenge, and an analysis of the previous published cases are presented. Twenty-nine patients (17 women, 12 men), aged 26.4 +/- 9.9 (12-43) years, were involved, receiving sulfasalazine (n = 11), mesalazine (n = 16), olsalazine (n = 1) or 5ASA without further informations (n = 1), for ulcerative colitis (n = 15), Crohn's disease (n = 13) or another indication (n = 1). The AP occurred in the first month of treatment in 71.4 per cent of the cases (n = 28). The clinical course was essentially benign in most of the cases. Recurrence of AP after rechallenge was observed in 17 of the 19 cases, even if the molecule, the dose or the form were modified. These results show that all 5ASA derivatives are potentially pancreatotoxic. An AP must be considered when an occurrence or increase of abdominal pain occurs during such therapy and warrants serum amylase assay and discontinuation of the drug.

Maintenance of remission of ulcerative colitis: a comparison between balsalazide 3 g daily and mesalazine 1.2 g daily over 12 months. ABACUS Investigator group

BACKGROUND

Despite widespread use of aminosalicylates as maintenance treatment for ulcerative colitis (UC), patients still report troublesome symptoms, often nocturnally.

AIM

To compare the efficacy and safety of balsalazide (Colazide) with mesalazine (Asacol) in maintaining UC remission.

METHODS

A randomized, double-blind comparison of balsalazide 3 g daily (1.04 g 5-ASA) and mesalazine 1.2 g daily for 12 months, in 99 (95 evaluable) patients in UC remission.

RESULTS

Balsalazide patients experienced more asymptomatic nights (90% vs. 77%, P=0.0011) and days (58% vs. 50%, N.S.) during the first 3 months. Balsalazide patients experienced more symptom-free nights per week (6.4+/-1.7 vs. 4.7+/-2.8; P=0.0006) and fewer nights per week with blood on their stools or on the toilet paper, mucus with their stools or with sleep disturbance resulting from symptoms or lavatory visits (each P < 0.05). Fewer balsalazide patients relapsed within 3 months (10% vs. 28%; P=0.0354). Remission at 12 months was 58%, in both groups. Similar proportions of patients reported adverse events (61% balsalazide vs. 65% mesalazine). There were five serious adverse events (two balsalazide, three mesalazine) and four withdrawals due to unacceptable adverse events (three balsalazide, one mesalazine), of which one in each group was also a serious adverse event.

CONCLUSIONS

Balsalazide 3 g/day and mesalazine 1.2 g/ day effectively maintain UC remission and are equally well tolerated over 12 months. At this dose balsalazide prevents more relapses during the first 3 months of treatment and controls nocturnal symptoms more effectively.

Olsalazine versus mesalazine in the treatment of mild to moderate ulcerative colitis

AIM

To compare the efficacy and tolerability of olsalazine sodium with enteric-coated mesalazine in inducing endoscopic remission in patients with mild to moderate active ulcerative colitis.

PATIENTS AND METHODS

Patients with mild to moderate active ulcerative colitis were randomized to receive either olsalazine sodium, 3 g/day (n = 88), or mesalazine, 3 g/day (n = 80), for up to 12 weeks.

RESULTS

Of the patients treated with olsalazine sodium, 52.2% achieved endoscopic remission, compared with 48.8% of patients treated with mesalazine. This difference was not significant (P = 0.67). There was a nonsignificant trend for patients with left-sided colitis or a more severe endoscopic grade to achieve remission if they were treated with olsalazine sodium than if they were treated with mesalazine. Both treatments were comparable with respect to clinical activity index and an investigator's global assessment. Seventy patients reported one or more adverse events; adverse events were seen in 45% of olsalazine sodium-treated patients and in 36% of mesalazine-treated patients. Eleven patients treated with olsalazine sodium and nine patients treated with mesalazine withdrew from the study because of adverse events. One patient treated with olsalazine sodium compared with two treated with mesalazine stopped treatment because of diarrhoea. Serious adverse events occurred in three patients treated with olsalazine sodium and in four treated with mesalazine.

CONCLUSION

Therapeutic effectiveness and tolerance to the treatment did not differ between olsalazine sodium, 3 g/day, and mesalazine, 3 g/day, in inducing endoscopic remission in patients with mild to moderate active ulcerative colitis within 12 weeks of treatment.

Balsalazide is more effective and better tolerated than mesalamine in the treatment of acute ulcerative colitis. The Abacus Investigator Group

BACKGROUND & AIMS

Aminosalicylates are widely used in the treatment of ulcerative colitis (UC). Balsalazide is a novel mesalamine prodrug, activated by colonic bacteria. The aim of this study was to compare the efficacy and safety of balsalazide with that of a pH-dependent formulation of mesalamine in active UC.

METHODS

A randomized, double-blind study was performed comparing balasalazide, 6.75 g daily, with mesalamine, 2.4 g daily, administered for 4, 8, or 12 weeks to 101 (99 evaluable) patients with symptomatic, sigmoidoscopically verified UC.

RESULTS

More patients treated with balsalazide achieved symptomatic remission after 2 (64% [balsalazide] vs. 43% [mesalamine]), 4 (70% vs. 51%), 8 (78% vs. 45%), and 12 weeks (88% vs. 57%) and complete remission (none/mild symptoms, sigmoidoscopy grade 0/1, no rectal steroid use within 4 days) after 4 (38% vs. 12%), 8 (54% vs. 22%), and 12 weeks (62% vs. 37%). Patients taking balsalazide experienced more asymptomatic days (4 weeks, 24% vs. 14%) and achieved the first asymptomatic day more rapidly (median, 10 vs. 25 days). Fewer patients in the balsalazide group reported adverse events (48% vs. 71%); four serious adverse events occurred in the mesalamine group.

CONCLUSIONS

Balsalazide is more effective and better tolerated than mesalamine as treatment for acute UC.

Olsalazine and 6-mercaptopurine-related bone marrow suppression: a possible drug-drug interaction

A patient with refractory Crohn's disease had two separate episodes of bone marrow suppression while receiving 50 to 75 mg 6-mercaptopurine a day and 1000 to 1750 mg olsalazine a day. This adverse reaction necessitated dose reduction of 6-mercaptopurine on the first occasion and withdrawal of 6-mercaptopurine and olsalazine on the second occasion. The patient's red blood cell thiopurine methyltransferase (TPMT) activity was 1.2 U per milliliter red blood cells (low normal range) and her TPMT genotype was wild-type sequence for all known alleles of TPMT that result in low TPMT enzyme activity. In vitro enzyme kinetic studies confirmed the hypothesis that olsalazine and olsalazine-O-sulfate are potent noncompetitive inhibitors of recombinant human TPMT. We suggest that the patient's relatively low baseline level of TPMT activity was inhibited by olsalazine and olsalazine-O-sulfate, leading to decreased clearance of 6-mercaptopurine and its accumulation. This ultimately increased intracellular 6-thiopurine nucleotide levels to toxic concentrations, which caused bone marrow suppression.

[New therapeutic possibilities in chronic inflammatory bowel diseases]

New therapeutic measures in inflammatory bowel diseases (IBD) are either based on actual data on disease pathogenesis or on new pharmaceutic preparations of known drugs. An overshooting immune response with T cell activation in the local gut associated immune system seems to be central in the etiopathogenesis of IBD. Modulation of the antigenic load in the gut lumen by parenteral or enteral nutrition or antibiotic treatment can alter disease activity. Immunosuppressive drugs are able to decrease the overshooting immune response. Azathioprin has its clear value in chronic active steroid dependent disease courses of Crohn's disease. According to recent studies, Methotrexate seems to be active as well, however, more studies are necessary. Several studies were not able to prove that Cyclosporine is of value in the treatment of Crohn's disease. Newer preparations of aminosalicylates have shown effectiveness in both active disease and prolongation of remission in Crohn's disease in high doses. Local release formulations of steroids with high first-pass-effect as Budesonide will have their indication in subgroups of IBD patients. However, systemic steroid application is still the gold standard in active disease.

Renal tubular dysfunction in patients with inflammatory bowel disease treated with aminosalicylate

BACKGROUND

An increasing number of case reports indicate potential nephrotoxicity of 5-aminosalicylic acid (5-ASA), which shares similarities with the chemical structures of both phenacetin and acetylsalicylic acid.

AIM

In a point prevalence study the occurrence of sensitive indices indicative of early kidney malfunction was assessed in outpatients with inflammatory bowel disease.

METHODS

Routine indices of kidney function (creatinine clearance, urinary protein content, pH, electrolytes, and microscopy) were investigated in 223 patients with inflammatory bowel disease as well as sensitive markers of glomerular or tubular dysfunction (microproteinuria by SDS polyacrylamide gel electrophoresis (SDS-PAGE), urinary concentrations of N-acetyl-beta-D-glucosaminidase, alpha 1-microglobulin, gamma-glutamyltransferase (GGT), alkaline phosphatase (AP), and albumin). Histories of exposure to 5-ASA were assessed by questionnaire.

RESULTS

Patients receiving high amounts of 5-ASA, both actual as well as on a lifetime basis, showed an increased prevalence of tubular proteinuria by SDS-PAGE. Raised values for urinary AP and GGT indicate proximal tubular epithelial cells as the source. All other kidney function tests were normal. Analysis of covariates indicated strong associations between disease activity and size of 5-ASA doses as well as alterations in kidney tubular function.

CONCLUSION

The possibility exists that high doses of 5-ASA may be associated with proximal tubular proteinuria. This point prevalence study cannot dissect the possible impact of chronic inflammation from high dose 5-ASA treatment and further prospective studies are warranted.

[Pneumonitis caused by mesalazine]

5-aminosalicylic acid (5-ASA) has been used to treat inflammatory bowel disease satisfactorily. Lung disease related to 5-ASA administration has been described only rarely. We report a case of alveolitis related to 5-ASA treatment in a woman with Crohn's disease. We review the literature and describe clinical, biological and radiological manifestations, along with the clinical course of this complication.

5-Aminosalicylates, sulfasalazine, steroid use, and complications in patients with ulcerative colitis

OBJECTIVES

The choice between sulfasalazine and 5-aminosalicylate (5-ASA) drugs in the management of patients with ulcerative colitis often depends on idiosyncrasies of drug tolerance and control of the disease in individual patients. We sought to evaluate whether there were population differences in the effect of 5-ASA and sulfasalazine on the occurrence of clinically recognized adverse events. We also attempted to determine whether there were differences in the use of concomitant steroids and in the rates of hospitalization.

METHODS

We reviewed a large computerized database drawn from general practices in the United Kingdom. There we found records of 2894 patients in whom general practitioners had diagnosed ulcerative colitis, and who were receiving ongoing medical therapy specific to ulcerative colitis. The period of data availability ran from the beginning of 1990 to the latter part of 1993. The average duration of observation was 2.1 yr per patient. Patient histories were categorized into distinct periods according to the dose of 5-ASAs and sulfasalazine, steroids, and immunosuppressants, and were further separated according to the activity of ulcerative colitis. Within these categories, we examined the initiation and discontinuation of steroids, incidence of new hospitalizations for ulcerative colitis, and clinical mention of adverse events.

RESULTS

New clinical mentions of hepatic, pancreatic, renal, and hematological events other than anemia were similar among the 5-ASAs and were very infrequent overall. Hospitalizations for ulcerative colitis occurred with similar frequency (about 15 hospitalizations per 100 patients per year) among users of those drugs. Patients receiving sulfasalazine had lower rates of initiation of prednisolone than did patients receiving 5-ASA, but sulfasalazine was used proportionately less often in patients who had been recently hospitalized, and it may be that sulfasalazine patients were somewhat less sick, overall, than were 5-ASA-using patients. The choice of drug did not affect discontinuation rates for prednisolone among established users.

CONCLUSIONS

In the United Kingdom, during the period of this study, serious adverse reactions to drugs were not an important aspect of the management of patients with ulcerative colitis. Renal and pancreatic complications of sulfasalazine and 5-ASA therapy were extremely rare. Sulfasalazine and 5-ASA drugs have similar steroid-sparing properties. Disease-specific hospitalizations are approximately 100 times more common in ulcerative colitis patients than are serious adverse drug effects. Considerations of drug efficacy should therefore dominate the choice between therapeutic agents.

Efficacy and tolerance of mesalazine suppositories vs. hydrocortisone foam in proctitis

BACKGROUND

Topical treatments with steroids or mesalazine are the most effective treatments for idiopathic proctitis.

AIM

To compare the efficacy and tolerance of mesalazine suppositories vs. hydrocortisone acetate foam in the treatment of acute proctitis.

PATIENTS AND METHODS

242 patients with active idiopathic proctitis were randomized to receive once daily either one Pentasa suppository (mesalazine 1 g) or 100 mg hydrocortisone (Colofoam) for 14-21 days (until remission). Disease activity and tolerance of the treatments were assessed using a daily questionnaire, by physician assessment, and endoscopy score.

RESULTS

Both treatments induced a significant reduction in disease activity. Mesalazine suppositories were significantly more effective than hydrocortisone on rectal blood loss (P = 0.002) and mucus (P = 0.02) parameters, and on the degree of the decrease in endoscopy score (P = 0.02). No significant difference was observed between treatments concerning histology or tolerance.

CONCLUSION

Mesalazine suppositories were as well-tolerated as hydrocortisone foam, but were more effective for some parameters of disease activity.

A randomized, placebo-controlled, double-blind trial of mesalamine in the maintenance of remission of Crohn's disease. The Canadian Mesalamine for Remission of Crohn's Disease Study Group

BACKGROUND & AIMS

The efficacy of mesalamine for the maintenance of remission in patients with Crohn's disease is controversial. The aim of this study was to conduct a double-blind, placebo-controlled study of mesalamine (750 mg four times a day for 48 weeks) in maintaining remission in 293 patients with Crohn's disease. Patients were stratified according to the method of induction of remission (medical or surgical).

METHODS

Patients were assessed at weeks 4, 12, 24, 36, and 48. Relapse was defined as a Crohn's Disease Activity Index of >150 (+60 points over baseline).

RESULTS

Of the 293 patients, 246 (84%) returned for at least 4 weeks of follow-up and were included in the final analysis. Thirty of the 118 (25%) who received mesalamine had a relapse compared with 47 of 128 (36%) receiving placebo (P = 0.056). Among those with relapse, the time to relapse was 119 days for the mesalamine-treated patients compared with 109 days for placebo-treated patients (P = NS). However, 25% of mesalamine-treated patients had relapsed by 249 days of follow-up compared with 154 days for placebo-treated patients. Subgroup analysis showed that patients with ileocecal-colonic disease or patients who were women had fewer relapses on mesalamine therapy than placebo-treated patients (21% vs. 41%, P = 0.018; and 19% vs. 41%, P = 0.003, respectively).

CONCLUSIONS

Mesalamine treatment reduced relapse compared with placebo treatment, although conventional statistical significance was not achieved.

[Drug therapy of ulcerative colitis]

The lethality of the severe ulcerative colitis has been markedly reduced in the last decades by drug and surgical therapy. The activity and extent of the disease is of immense importance for the drug therapy. In the last 30-40 years numerous controlled clinical trials provided treatment options for the active ulcerative colitis and maintenance of remission. This paper should give a short overview of the standard therapy.

A trial of zileuton versus mesalazine or placebo in the maintenance of remission of ulcerative colitis. The European Zileuton Study Group For Ulcerative Colitis

BACKGROUND & AIMS

Leukotriene B4 is a major neutrophil chemoattractant detected during relapse of inflammatory bowel disease and represents a potentional therapeutic target. The aim of this study was to compare the efficacy of zileuton, an active 5-lipoxygenase inhibitor, with mesalazine and placebo in the maintenance of remission in ulcerative colitis.

METHODS

A double-blind, parallel-group, multicenter, and multinational trial was conducted during a 6-month period in hospital-based patients with inflammatory bowel disease. Three hundred five evaluable patients with ulcerative colitis in remission at the start of the trial were randomized into groups to undergo oral treatment with zileuton (600 mg qid; n = 113), mesalazine (400 mg qid; n = 99), or placebo (n = 111). The primary efficacy outcome was maintenance of remission for 6 months. A multivariate analysis was used to investigate determinants of relapse. Safety was assessed by treatment discontinuation, adverse events, vital signs, and laboratory parameters.

RESULTS

After 6 months, 54% of patients receiving zileuton remained in remission compared with 43% receiving placebo (P = 0.094) and 63% on mesalazine (P = 0.266). Relapse rates on mesalazine were significantly lower than those for placebo (P = 0.017). All treatments were well tolerated.

CONCLUSIONS

Zileuton (600 mg qid) was not significantly better than placebo in the maintenance of remission of ulcerative colitis in this trial and may have limited potential in the treatment of this condition.