THE MODE OF ACTION OF THE AMINOSALICYLATES IN INFLAMMATORY BOWEL-DISEASE

Sulphasalazine and other 5-aminosalicylic acid (5-ASA)-containing drug s are used in the treatment of acute inflammatory bowel disease and in the maintenance of clinical remission. Despite their use for over 50 years, the mechanism of action of this class of drugs remains uncertai n, although a number of possibilities are discussed in this review. It seems likely that the aminosalicylates are important free radical sca vengers, can reduce leukotriene production and can inhibit the cellula r release of interleukin-1, all of which are likely to be important in reducing the acute inflammatory response in inflammatory bowel diseas e. The effects of these drugs on prostaglandin production are more con tentious, but it appears that 10(-5) to 10(-4) M concentrations stimul ate production of prostaglandins which may be cytoprotective, while hi gher doses of these drugs inhibit prostaglandin production. The aminos alicylates may maintain remission in inflammatory bowel disease by pre venting leucocyte recruitment into the bowel wall. The drugs inhibit t he chemotactic response to leukotriene B4, reduce the synthesis of pla telet activating factor and also inhibit leucocyte adhesion molecule u pregulation.