Treatment of inflammatory bowel disease: safety and tolerability issues

An examination is needed of the potential adverse effects of the agents most commonly used to treat inflammatory bowel disease. Most of these therapies can be used safely to induce or maintain remissions, although some aspects of monitoring for toxicity are necessary. Aminosalicylates, including sulfasalazine and mesalamine delivery systems, are most commonly associated with sulfa-related effects (sulfasalazine) or intolerance, with rare instances of nephritis, pulmonitis, hepatitis, or worsening colitis. The immunomodulators are most commonly associated with bone marrow suppression, hepatitis, and the risk of opportunistic infections. Methotrexate is contraindicated in pregnancy. Antibiotics used for inflammatory bowel disease are generally safe and well tolerated, although metronidazole carries a long-term risk of peripheral neuropathy. The well-recognized multitude of adverse effects from corticosteroids are eliminated or minimized when rapidly metabolized steroids, such as budesonide, are used.

Drug utilization study in patients with Crohn's disease in Spain

OBJECTIVE

To discover the therapeutic strategies for Crohn's disease used in Spain and to analyse the factors associated with the use of each treatment.

DESIGN

Observational, cross-sectional study of patients with Crohn's disease who attended hospitals in Spain.

METHODS

Two structured questionnaires were used, one completed by gastroenterologists about demographic clinical data and disease activity, and the other a telephone interview with the patients to obtain epidemiological and drug utilization data.

RESULTS

A total of 635 patients from 39 hospitals were included. Aminosalicylates (77%) and corticosteroids (41%) were the most commonly used drugs. Monotherapy was used in 52% of the patients and was associated with less severe disease and relapse. Aminosalicylate use was associated with relapse and associated inversely with use of immunosuppressors. Corticosteroid use was associated with relapse, disease activity, and emergency visit frequency, and associated inversely with perianal disease. Use of immunosuppressors was associated with perianal disease, chronic active disease, and routine visit frequency, and associated inversely with aminosalicylate use. Antibiotic use was associated with relapse, perianal disease, chronic active disease and hospitalization.

CONCLUSION

Aminosalicylates, corticosteroids and a combination of both drugs are the drugs used most frequently against Crohn's disease in Spain. Gender, age, clinical pattern and location were not associated with the type of drug used either in monotherapy or in combined therapy.

Inflammatory bowel disease in pregnancy

Women and men with inflammatory bowel disease (IBD) frequently express concerns about fertility and pregnancy. The evidence suggests that women with IBD can expect to have a normal pregnancy outcome provided they have inactive disease. They have an increased risk of having a small or premature baby but the majority will have a normal outcome of pregnancy. The commonly used drugs appear to be safe and well tolerated in pregnancy. There remains a need for further studies in this area to help in the difficult decisions about the management of IBD around the time of conception and during pregnancy.

Balsalazide is superior to mesalamine in the time to improvement of signs and symptoms of acute mild-to-moderate ulcerative colitis

OBJECTIVE

Balsalazide is a novel azo-bonded 5-aminosalicylic acid treatment for mild-to-moderate ulcerative colitis. The study objective was to compare symptomatic remission rates with balsalazide and mesalamine while controlling for extent of disease and time since diagnosis in patients with active, mild-to-moderate ulcerative colitis.

METHODS

A total of 173 patients with sigmoidoscopically verified ulcerative colitis were randomized to 8 wk of double-blind treatment with balsalazide 6.75 g/day or mesalamine 2.4 g/day. Both treatments provided 2.4 g/day of oral 5-aminosalicylic acid. Patients maintained symptom diaries throughout the treatment period.

RESULTS

Overall, 46% of balsalazide- and 44% of mesalamine-treated patients achieved symptomatic remission. Higher response rates were noted in newly diagnosed patients with < or = 40 cm of disease (68% vs 61%) than in recently relapsed patients with >40 cm of disease (36% vs 25%). The median time to symptomatic remission was 12 days shorter with balsalazide (25 days) than with mesalamine (37 days). Significantly more balsalazide patients showed sigmoidoscopic (p = 0.002), stool frequency (p = 0.006), rectal bleeding (p = 0.006), and physician's global assessment score (p = 0.013) improvement by 14 days than did mesalamine patients. Similar proportions of patients reported adverse events (54% vs 64%), which were most commonly related to the gastrointestinal and central and peripheral nervous systems.

CONCLUSIONS

Balsalazide is an effective and safe treatment for mild-to-moderate ulcerative colitis. Improvement of symptoms occurs considerably earlier with balsalazide than with mesalamine.

Balsalazide: a review of its therapeutic use in mild-to-moderate ulcerative colitis

The aminosalicylate balsalazide is a prodrug which is metabolised by bacterial azo reductases in the colon to release its therapeutically active moiety mesalazine [mesalamine (US) or 5-aminosalicylic acid] and an inert carrier molecule. The systemic absorption of balsalazide and its metabolites is not required for the therapeutic efficacy of the drug, and has been demonstrated to be limited. Data from well designed trials with a duration of 8 to 12 weeks show that oral balsalazide 6.75 g/day is as effective as (two trials) or more effective than (one trial) oral delayed-release (pH-dependent) mesalazine 2.4 g/day and appears to be as effective as oral sulfasalazine 3 g/day in the treatment of active mild-to-moderate ulcerative colitis. In addition, balsalazide appears to have a faster onset of action than mesalazine. Furthermore, balsalazide was as effective as delayed-release mesalazine (dosages used were 1.2 and 1.5 g/day, where 1.6 g/day is recommended) and oral sulfasalazine 2 g/day (recommended dosage) in the prevention of relapse in ulcerative colitis in remission after 6 to 12 months of treatment; the balsalazide dosage was 3 g/day versus mesalazine and 2 g/day versus sulfasalazine. Although not well established, additional benefits may be achieved with balsalazide dosages up to 6 g/day. Data from well designed, 2- to 12-month trials show that balsalazide is well tolerated by patients with ulcerative colitis in both acute and maintenance indications, and is better tolerated than standard formulations of sulfasalazine at therapeutically relevant dosages.

CONCLUSION

Balsalazide is a well tolerated and effective first-line therapeutic option for patients with ulcerative colitis, both for the treatment of active mild-to-moderate disease and as maintenance therapy to prevent disease relapse.

A randomized, double blind, dose-response comparison of balsalazide (6.75 g), balsalazide (2.25 g), and mesalamine (2.4 g) in the treatment of active, mild-to-moderate ulcerative colitis

OBJECTIVE

Balsalazide is a new innovative, mesalamine-containing prodrug that is activated by bacteria in the colon. Balsalazide has been shown previously to be well tolerated and effective in the treatment of acute ulcerative colitis. The aim of this study was to determine the dose-response of balsalazide for efficacy and safety in active, mild-to-moderate ulcerative colitis and to compare this profile with that of mesalamine, pH-dependent, delayed-release tablets.

METHODS

A multicenter, randomized, active control, double-blind, double-dummy, dose-response, parallel-group study was performed comparing balsalazide (6.75 g daily), balsalazide (2.25 g daily), and mesalamine (2.4 g daily), administered for 8 wk to 154 patients with active, mild-to-moderate ulcerative colitis as verified by sigmoidoscopy.

RESULTS

Eight weeks of treatment with 6.75 g of balsalazide daily provided significantly greater improvement than did balsalazide (2.25 g daily) in rectal bleeding (64.7% [6.75-g balsalazide] vs 32.4% [2.25-g balsalazide], p < 0.006), stool frequency (58.8% vs 29.4%, p < 0.006), sigmoidoscopic score (78.9% vs 52.5%, p < 0.015), and Physician's Global Assessment (73.7% vs 51.3%, p < 0.03). The efficacy of balsalazide showed a significantly more rapid onset of action than that of mesalamine (2.4 g daily) (2-wk sigmoidocopic score improvement, 54.7% [6.75-g balsalazide] vs 29.4% [2.4-g mesalamine], p = 0.006) with numerically greater improvement at 8 wk in five of seven measured signs and symptoms. Balsalazide (6.75 g daily) was well tolerated, and the safety profile did not differ significantly from that of balsalazide (2.25 g daily) or mesalamine.

CONCLUSIONS

Eight weeks of treatment with balsalazide (6.75 g daily) is significantly more effective than balsalazide (2.25 g daily) and more rapid in onset than mesalamine (2.4 g daily) in improving signs and symptoms of acute ulcerative colitis. Balsalazide (6.75 g daily) is well tolerated, and the safety profile does not differ from that of balsalazide (2.25 g daily) and mesalamine (2.4 g daily).

Review article: monitoring for drug side-effects in inflammatory bowel disease

The side-effects suitable for monitoring in patients with inflammatory bowel disease being treated with the four main groups of drugs (5-aminosalicylic acid preparations, azathioprine and 6-mercaptopurine, methotrexate, and corticosteroids) are reviewed. On the basis of the reported frequency, severity and timing of side-effects, a practical scheme of monitoring is recommended. This includes a baseline measurement of full blood count, creatinine and liver function tests in all patients. In the absence of worrying symptoms, we recommend the following: (i) no monitoring for sulfasalazine; (ii) for other 5-aminosalicylic acid preparations, the measurement of creatinine at 6 and 12 months and then annually; (iii) for azathioprine/6-mercaptopurine, thiopurine methyltransferase genotype/phenotype determination has no role in treatment monitoring, but a full blood count at 2 weeks, 1 month, 3 months and then every 3 months should be performed; (iv) for methotrexate, a full blood count and liver function tests should be performed every 3 months; (v) for steroids, dual energy X-ray absorptiometry bone scanning should be performed at the start of therapy, every year in which steroids are used if the T score is < 0, and every 3-5 years if the T score is > 0.

Evaluation of renal function following treatment with 5-aminosalicylic acid derivatives in patients with ulcerative colitis

BACKGROUND

A number of cases of nephrotoxicity have been reported in patients with inflammatory bowel disease taking oral 5-aminosalicylic acid (5-ASA).

AIM

To evaluate the effects of 9 months of therapy with mesalazine or olsalazine on renal function in patients with ulcerative colitis in remission.

METHODS

Forty patients with ulcerative colitis in complete remission for 6 months were randomized to either olsalazine (n=20) or mesalazine (n=20 for nine months). Thirty-six of the 40 patients were on prior salicylate therapy. Disease activity was the measure ofclinical efficacy and was assessed by the Harvey-Bradshaw Index (HBI). Laboratory efficacy measurements included glomerular filtration rate (GFR), microalbuminuria, urinary gluthathione S-transferase (GST) and serum C-reactive protein (CRP). Safety analysis consisted of documentation of adverse events and laboratory values.

RESULTS

There was no significant reduction in the GFR overall on therapy. The levels of GFR adjusted for baseline were similar in the two treatment groups after 3, 6 and 9 months. A significantly higher percentage of mesalazine-treated patients experienced drug related adverse events, all of a minor nature. The incidence of adverse events causing early withdrawal was similar in the two treatment groups.

CONCLUSION

Treatment with mesalazine or olsalazine for 9 months had no significant impact on GFR.

A double-blind comparison of balsalazide, 6.75 g daily, and sulfasalazine, 3 g daily, in patients with newly diagnosed or relapsed active ulcerative colitis

BACKGROUND

Sulfasalazine is well established in the treatment of active ulcerative colitis. Intolerance to sulfasalazine, however, is a common problem. Balsalazide has been designed to deliver 5-aminosalicylic acid to the colon without the poor tolerability of sulfasalazine.

AIM

To compare the safety and efficacy of balsalazide, 6.75 g daily, with sulfasalazine, 3 g daily, in the treatment of active ulcerative colitis of all grades of severity.

METHODS

Balsalazide and sulfasalazine were compared in a multicentre, double-blind, parallel group study over 12 weeks. Patients were stratified for disease severity and topical and/or oral steroids were co-administered where clinically necessary.

RESULTS

Fifty-seven patients were randomized: 28 to receive balsalazide and 29 to receive sulfasalazine. Significantly fewer patients withdrew from the balsalazide group due to adverse events (2/28 vs. 9/29, P=0.041). These data confirm that balsalazide is better tolerated than sulfasalazine. In patients able to tolerate the treatment, similar improvements were recorded in clinical, sigmoidoscopic and histological assessments in both treatment groups.

CONCLUSIONS

This study confirms the better tolerability of balsalazide compared to sulfasalazine, and supports the use of balsalazide in ulcerative colitis of all grades of severity.

A double-blind comparison of balsalazide, 6.75 g, and sulfasalazine, 3 g, as sole therapy in the management of ulcerative colitis

BACKGROUND

Sulfasalazine is accepted therapy for active ulcerative colitis, but side-effects and intolerance are common. Balsalazide is an azo-bonded pro-drug which also releases 5-aminosalicylic acid into the colon, but uses an inert carrier molecule.

AIM

To compare the safety and efficacy of sul- fasalazine, 3 g, with balsalazide, 6.75 g, in the initial daily treatment of mild to moderate ulcerative colitis.

METHODS

A randomized, multicentre, double-blind, parallel group study was performed, with a treatment duration of 8 weeks. Patients on previous maintenance treatment were excluded. The trial medication was the sole treatment for the colitis. Efficacy was assessed by patient diaries, symptom assessment, sigmoidoscopic appearance and histology.

RESULTS

Fifty patients were recruited: 26 allocated to the balsalazide group and 24 to the sulfasalazine group. More patients withdrew due to adverse events in the sulfasalazine group (nine patients vs. one patient in the balsalazide group, P=0.004). Improvement occurred in both groups, with a tendency to a faster response with balsalazide. Of the patients taking balsalazide, 61% achieved clinical and sigmoidoscopic remission.

CONCLUSIONS

Balsalazide, 6.75 g, is effective as the sole treatment for patients with mild to moderately active ulcerative colitis, with significantly fewer withdrawals due to side-effects than in a similar group of patients taking sulfasalazine, 3 g.

Maintenance drugs for inflammatory bowel disease

Ulcerative colitis and Crohn's disease are chronic relapsing inflammatory disorders of the bowel that affect 2-4 per 1,000 people in Northern Europe. The course of these diseases is difficult to predict and relapses can occur many years after presentation. Various drugs (and/or surgery in Crohn's disease) are used to induce remission, and maintenance drug therapy is commonly given to prevent relapse once remission is achieved. Here, we consider maintenance drug treatment, in particular the size and duration of benefit and potential short-term and long-term risks associated with such therapy.

Low dose balsalazide (1.5 g twice daily) and mesalazine (0.5 g three times daily) maintained remission of ulcerative colitis but high dose balsalazide (3.0 g twice daily) was superior in preventing relapses

BACKGROUND

Balsalazide is a new 5-aminosalicylic acid (5-ASA) containing prodrug. Its efficacy in comparison with standard mesalazine therapy and the optimum dose for maintaining remission of ulcerative colitis are still unclear.

AIMS

To compare the relapse preventing effect and safety profile of two doses of balsalazide and a standard dose of Eudragit coated mesalazine.

METHODS

A total of 133 patients with ulcerative colitis in remission were recruited to participate in a double blind, multicentre, randomised trial: 49 patients received balsalazide 1.5 g twice daily, 40 received balsalazide 3.0 g twice daily, and 44 received mesalazine 0.5 g three times daily. Efficacy assessments were clinical activity index (CAI) and endoscopic score according to Rachmilewitz, and a histological score. In addition, laboratory tests were performed and urinary excretion of 5-ASA and its metabolite N-Ac-5-ASA was analysed. The study lasted for 26 weeks.

RESULTS

Balsalazide 3.0 g twice daily resulted in a significantly higher clinical remission rate (77.5%) than balsalazide 1.5 g twice daily (43.8%) and mesalazine 0.5 g three times daily (56.8%) (p=0.006). The respective times to relapse were 161 days, 131 days (p=0.003), and 144 days (NS). Accordingly, pairwise contrasts of the final endoscopic score demonstrated a significant difference (p=0.005) between the two balsalazide treatment groups while differences between either of these two groups and mesalazine were not statistically significant. Patients treated with balsalazide excreted less 5-ASA and N-Ac-5-ASA than patients receiving mesalazine but these differences were not statistically significant. Discontinuation of the trial because of adverse effects occurred in nine patients: three in the balsalazide 1.5 g twice daily group, two in the balsalazide 3.0 g twice daily group, and four in the mesalazine 0.5 g three times daily group. No clinically important new drug safety related findings were identified in this study.

CONCLUSIONS

High dose balsalazide (3.0 g twice daily) was superior in maintaining remission in patients with ulcerative colitis compared with a low dose (1.5 g twice daily) or a standard dose of mesalazine (0.5 g three times daily). All three treatments were safe and well tolerated.

Leucopenia resulting from a drug interaction between azathioprine or 6-mercaptopurine and mesalamine, sulphasalazine, or balsalazide

AIM

We evaluated the effect of coadministration of sulphasalazine, mesalamine, and balsalazide on the pharmacokinetics and pharmacodynamics of azathioprine and 6-mercaptopurine.

METHODS

Thirty four patients with Crohn's disease receiving azathioprine or 6-mercaptopurine were enrolled in an eight week non-randomised parallel group drug interaction study and treated with mesalamine 4 g/day, sulphasalazine 4 g/day, or balsalazide 6.75 g/day. The primary outcome measure was the occurrence of clinically important leucopenia during the study, defined separately as total leucocyte counts < 3.0 x 10(9)/l and < or = 3.5 x 10(9)/l. Whole blood 6-thioguanine nucleotide concentrations were determined.

RESULTS

Three patients could not be evaluated for the primary outcome measure. In the remaining 31 patients, the frequency of total leucocyte counts < 3.0 and < or = 3.5 were: 1/10 and 5/10 in the mesalamine group; 1/11 and 6/11 in the sulphasalazine group; and 0/10 and 2/10 in the balsalazide group. There were significant increases in mean whole blood 6-thioguanine nucleotide concentrations from baseline at most time points in the mesalamine and sulphasalazine groups but not in the balsalazide group.

CONCLUSIONS

In patients with Crohn's disease receiving azathioprine or 6-mercaptopurine, coadministration of mesalamine, sulphasalazine, and possibly balsalazide results in an increase in whole blood 6-thioguanine nucleotide concentrations and a high frequency of leucopenia.

Review article: balsalazide therapy in ulcerative colitis

Balsalazide is a 5-aminosalicylic acid (mesalazine) pro-drug which has an inert carrier molecule instead of the sulfapyridine moiety of sulfasalazine. It is designed to deliver 5-aminosalicylic acid to the colonic mucosa without the sulfapyridine-associated side-effects encountered with sulfasalazine. Several studies have confirmed the efficacy and patient tolerance of balsalazide. When compared to mesalazine at equivalent doses, it induced symptomatic and complete remission of acute ulcerative colitis in a greater proportion of patients. In particular, patients with resistant left-sided disease were shown to have a higher probability of achieving remission. Balsalazide was beneficial in patients with troublesome nocturnal symptoms. It has a similar efficacy in maintaining remission when compared to sulfasalazine and mesalazine. The advantage of balsalazide over other 5-aminosalicylic acid compounds is its superior patient tolerability with minimal side-effects.

Tolerability of aminosalicylates in inflammatory bowel disease

Since its synthesis in the 1930s and subsequent introduction, sulfasalazine has been an effective treatment for inflammatory bowel disease. However, up to one-third of patients are unable to take the drug because of severe intolerance. The finding in 1977 that the anticolitic effect of sulfasalazine lay in its 5-aminosalicylic [(5-ASA); mesalazine] moiety led to the development of new generations of 5-ASA agents. These new agents include a slow continuous release formulation, pH-dependent release formulations, formulations using alternative carrier molecules and rectally administered formulations. Newer 5-ASA formulations are more effective than placebo in maintaining remission of ulcerative colitis. They have also been used for the treatment of active Crohn's disease as well as maintenance treatment of ileocolonic Crohn's disease, although their role in isolated small bowel disease is controversial. In general terms, all of the newer 5-ASA preparations are much better tolerated than sulfasalazine. The use of standard dosages of mesalazine in pregnancy appears to be tolerated; however, continuing surveillance of pregnancy outcome is recommended. While there is evidence that mesalazine can cause nephrotoxic reactions, these reactions can occur with all 5-ASA-containing preparations, particularly in individuals with existing renal disease. Blood dyscrasias can also occur with all aminosalicylates.

Minimal renal dysfunction in inflammatory bowel disease is related to disease activity but not to 5-ASA use

BACKGROUND

Conflicting data exist about proteinuria in inflammatory bowel diseases. It is still unclear whether the occurrence of proteinuria in inflammatory bowel disease patients is an extra-intestinal manifestation of disease or the result of adverse effects to medication, especially to aminosalicylates (ASA).

METHODS

A total of 95 patients (51 with Crohn's disease and 44 with ulcerative colitis) were enrolled in the study. Disease activity was assessed by Crohn's Disease Activity Index (CDAI) or the Truelove index, respectively. Urine was collected over 24 h and protein excretion of specific marker proteins for tubular (alpha 1-microglobulin-alpha 1-MG) and glomerular (albumin-Alb, Immunoglobulin G-IgG) dysfunction was measured using a highly sensitive immunoluminometric assay.

RESULTS

Out of 51 Crohn's disease patients, 20 showed elevated urinary alpha 1-MG. The amount of alpha 1-MGuria was strongly correlated to the CDAI (r=0.6, P < 0.001). Only four Crohn's disease patients showed slightly elevated values for glomerular proteins in urine. Similar results were obtained for ulcerative colitis: whereas only two ulcerative colitis patients showed albuminuria, tubular proteinuria was detected in 28 out of 44 ulcerative colitis patients. Proteinuria was strongly dependent on disease activity (P < 0.01) but was not related to ASA treatment.

CONCLUSIONS

Proteinuria of tubular marker proteins occurs in the majority of inflammatory bowel disease patients and is related to disease activity rather than to ASA treatment. Tubular proteinuria seems to reflect a renal extra-intestinal manifestation of inflammatory bowel disease and may serve as a new relevant marker of disease activity.

Glomerular and tubular renal functions after long-term medication of sulphasalazine, olsalazine, and mesalazine in patients with ulcerative colitis

To date there are only few reports evaluating the potential nephrotoxic reactions of the new 5-aminosalicylic acid (5-ASA) preparations in patients with ulcerative colitis (UC). The aim of this study was to screen the tubular and glomerular functions in patients with UC in maintenance treatment with either 5-ASA azo-compounds (sulphasalazine and olsalazine) or mesalazine. Patients with UC in clinical remission treated with either sulphasalazine, olsalazine, or mesalazine for more than 1 year were included in an open, single-blind retrospective Norwegian multicenter study. Serum and urine creatinine, serum and urine beta2-microglobulin, urine N-acetyl-beta-glucoseamidase (NAG), urine alkaline phosphatase, urine microalbumin, urine alanine amino peptidase, and urine beta2-microglobulin were measured. Fifty-two females and 75 males (n = 127), ages 20-69, were evaluated. Thirty-six patients were treated with sulphasalazine (mean treatment time 10.1+/-6.6 years [mean +/- SD]), 32 patients were treated with olsalazine (2.3+/-1.4 years), and 59 patients with mesalazine (3.2+/-2.0 years). At inclusion, there were no significant differences in the serum or urine values between the groups. In 17 patients (1 patient [3%] in the sulphasalazine group, 4 patients [13%] in the olsalazine group, and 12 patients [20%] in the mesalazine group), at least one abnormal serum and/or urine value was detected. After 10 years of treatment, only one abnormal value was found among the 19 patients in the sulphasalazine group. The abnormal values observed in the other groups indicated minor glomerular or tubular renal damage. In conclusion, long term sulphasalazine treatment appears to be safe and free of nephrotoxic side effects, whereas minor glomerular and tubular impairment are observed in a few patients treated with olsalazine and mesalazine.

Acute pancreatitis in a child with idiopathic ulcerative colitis on long-term 5-aminosalicylic acid therapy

Acute pancreatitis is a rare but known complication of inflammatory bowel disease in adults. In children, only a few cases with this complication have been reported. We describe a 10-year-old boy with ulcerative colitis who developed acute pancreatitis while on long-term treatment with 5-aminosalicylic acid.

The role of aminosalicylates at the beginning of the new millennium in the treatment of chronic inflammatory bowel disease

OBJECTIVE

To discuss the pharmacological properties of aminosalicylates and their potential value in the treatment of chronic inflammatory bowel disease (IBD).

METHODS

A review of clinical studies on the pharmacokinetics and mode of action of aminosalicylates is provided. In addition, the clinical efficacy and safety of aminosalicylates in the treatment of IBD, according to several recent meta-analyses, is summarised.

RESULTS

Whereas aminosalicylates represent drugs of first choice in the acute treatment of ulcerative colitis and also for maintaining those patients in remission, their value for patients with Crohn's disease, either for achieving or maintaining remission, is at best modest. There is a large variability in the clinical results, especially in Crohn's disease, which is probably due to the variable extent and severity of IBD, different instruments in the evaluation of therapeutic outcome, and also at least partly caused by the different preparations and dosages of aminosalicylates used, as well as the high variation in drug disposition and topical availability of the active drug. The popular use of aminosalicylates is most likely due to the low incidence of side effects and the good overall safety records of mesalazine (mesalamine).

CONCLUSIONS

Apparently, the full therapeutic potential of aminosalicylates has not yet been evaluated (e.g. upper dosage range, combination therapy, responding subgroups). Consequently, the imperfect treatment might be improved in the new millennium by novel insights in the complex mode of action of mesalazine as well as in the etiopathogenesis of IBD.