Review article: induction therapy for patients with active ulcerative colitis.

5-aminosalicylic acid (mesalazine) is considered first-line therapy for active mild-moderate, left-sided or extensive ulcerative colitis. With modern delayed-release formulations, conventional doses are very well tolerated, and there is accumulating evidence that increasing the dose, to >4 g/day, leads to higher response rates and earlier symptom relief in patients with ulcerative colitis. There is evidence that combining oral and rectal (enema) formulations of 5-aminosalicylic acid leads to faster and higher remission rates. Despite the fact that clinical trials in ulcerative colitis have often used different endpoints, making it difficult to make objective comparisons, the evidence now strongly suggests that it is appropriate to start patients with mild or moderately active ulcerative colitis on doses of 5-aminosalicylic acid of at least 4 g/day. For those with extensive disease, adding rectal 5-aminosalicylic acid improves remission rates; the same seems likely to be true for limited disease, but robust evidence is lacking. Rectal 5-aminosalicylic acid may in fact be sufficient on its own for patients with active proctitis. Patients with mild-moderate ulcerative colitis who do not improve within 2 weeks of high-dose 5-aminosalicylic acid should have treatment augmented by oral steroids.