Ulcerative colitis medication, Mezavant XL, in packaging. Mezavant is a brand name for tablets of mesalazine (or mesalamine in the United States). Mesalazine is an anti-inflammatory drug that is metabolized in the gut. It is used to reduce inflammation in the intestines due to a condition called ulcerative colitis, which typically arises in the rectum and often extends to involve part of, or most of, the large intestine.