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Evidence summaries

Oral 5-Aminosalicylic Acid for Maintenance of Remission in Ulcerative Colitis

The newer 5-ASA preparations are more effective than placebo in maintenance of remission in ulcerative colitis, but less effective than sulphasalazine (SASP). Level of evidence: "A"

A Cochrane review [Abstract] 1 included 41 studies comparing 5-ASA to placebo, with a total of 8928 subjects.

5-ASA was significantly superior to placebo for maintenance of clinical or endoscopic remission. 41% of 5-ASA patients relapsed compared to 58% of placebo patients (7 studies, 1298 patients; RR 0.69, 95% CI 0.62 to 0.77). There was a trend towards greater efficacy with higher doses of 5-ASA with a statistically significant benefit for the 1 to 1.9 g/day (RR 0.65; 95% CI 0.56 to 0.76) and the > 2 g/day subgroups (RR 0.73, 95% CI 0.60 to 0.89). SASP was significantly superior to 5-ASA for maintenance of remission. 48% of 5-ASA patients relapsed compared to 43% of SASP patients (12 studies, 1655 patients; RR 1.14, 95% CI 1.03 to 1.27).

No statistically significant differences in efficacy or adherence were found between once daily and conventionally dosed 5-ASA. 21% of once daily patients relapsed over 12 months compared to 31% of conventionally dosed patients (8 studies, 3127 patients; RR 0.91, 95% CI 0.82 to 1.01). 11% of patients in the once daily group failed to adhere to their medication regimen compared to 9% of patients in the conventional dosing group (6 studies, 1462 patients; RR 1.22, 95% CI 0.91 to 1.64).

There does not appear to be any difference in efficacy among the various 5-ASA formulations. Forty-four per cent of patients in the 5-ASA group relapsed compared to 41% of patients in the 5-ASA comparator group (6 studies, 707 patients; RR 1.08, 95% CI 0.91 to 1.28). Common adverse events included flatulence, abdominal pain, nausea, diarrhea, headache, dyspepsia, and nasopharyngitis. There were no statistically significant differences in the incidence of adverse events between 5-ASA and placebo, 5-ASA and SASP, once daily and conventionally dosed 5-ASA, 5-ASA and comparator 5-ASA formulations and 5-ASA dose ranging studies. The trials that compared 5-ASA and SASP may have been biased in favour of SASP because most trials enrolled patients known to be tolerant to SASP which may have minimized SASP-related adverse events.

    References

    • Wang Y, Parker CE, Feagan BG et al. Oral 5-aminosalicylic acid for maintenance of remission in ulcerative colitis. Cochrane Database Syst Rev 2016;(5):CD000544. [PubMed].

Primary/Secondary Keywords