Treatment of mildandmoderateforms of ulcerativecolitis: the possibilities of mesalazine

The article indicates the specific niche and principles for choosing mesalazine formulations, and the selection of a dose for the treatment of mild to moderate extensive (left-sided and total) ulcerative colitis (UC). It doesn’t consider any approaches to the treatment of more severe UC or distal UC (proctitis). The current concepts on the use of 5-aminosalicylic acid (5-ASA) formulations to induce and maintain remission in mild to moderate active UC are discussed. The principles for drug administration and a comparative analysis of domestic and international mesalazine dosing recommendations are provided. The guidelines place special emphasis on the importance of high-dose mesalazine therapy (≥4 g/day), which allows to achieve the targets set by the Treat-to-target (T2T) strategy and to reach the clinical and endoscopic remission. The evidence from meta-analyses and comparative studies demonstrating the same efficacy of different forms of mesalazine in the treatment of UC are presented. Attention is drawn to the choice of the optimal drug with enteric coating that consists of two types of Eudragit (Eudragit L and Eudragit S) in contrast to mesalazine formulations with one and the same type of coating (only L or only S). The double Eudragit (L + S) pH-dependent coating of mesalazine tablets dissolves in the terminal ileum, cecum and partially in the right half of the colon at pH 6–7.5, while formulations coated with only L or S dissolve at a narrower pH range. The clinical efficacy of mesalazine directly depends on its intraluminal concentration that is determined by the amount of the released drug according to the pH level in the intestinal lumen. The double Eudragit coating allows to cover the entire pH range in the ileum and colon. The paper presents evidence from the domestic clinical practice that confirms the Cochrane meta-analysis statements on the comparable efficacy of different mesalazine formulations concerning the targets to reach remission and reduce the level of fecal calprotectin. In addition, a high incidence of clinical remissions (more than 80% at 48 weeks of treatment) on double coated (L + S) mesalazine is demonstrated.