Medical therapy of inflammatory bowel disease for the 21st century

Abstract

Inflammatory bowel disease therapy can be considered in several subcategories, and this review is designed to provide selective updates for some of the most important therapeutic entities currently marketed or soon to be available for the medical management of IBD. Although conventional corticosteroids have been a major component of acute inflammatory bowel disease management, steroids have many serious disadvantages; and toxicity is heightened with chronic steroid therapy. Newer corticosteroids, particularly budesonide, may be less toxic than older agents such as prednisone. Budesonide may be used as an enema in active distal ulcerative colitis (UC) or as delayed release tablets in Crohn's disease (CD). However, budesonide is not completely free from steroid side effects, and may share in some of the toxicity of older corticosteroids, particularly when high dose budesonide is administered. Topical and oral aminosalicylates are widely utilized for the treatment of mild to moderate active UC and mild active CD, and they also are efficacious for maintenance of IBD remission. Recent data continue to support the concept that higher doses and prolonged use of mesalamine-based drugs are therapeutically superior to lower doses and short term treatment. In addition, the combination of oral and rectal aminosalicylate formulations often succeeds in patients refractory to either used alone. The immunomodulatory drugs azathioprine and 6-mercaptopurine are particularly effective in treating both CD and UC, and methotrexate has also shown some promise in CD therapy. Immunosuppressive therapy for inflammatory bowel disease initially met with strong physician resistance. However, views have shifted in response to positive data on the utility of immunosuppressive agents in many cases of IBD. Although cyclosporine may be used as a 'rescue' medication in some severe IBD cases, it has been associated with severe toxic reactions. Possible candidates for cyclosporine treatment should be offered such therapy only in academic centers highly experienced with the nuances of this modality. Clinical trials of the newer entities IL-10, IL-11, tacrolimus, and anti-TNFalpha, have demonstrated variable efficacy in refractory IBD patients. Anti-TNFalpha has been very impressive, particularly in the presence of fistulizing Crohn's disease. Many physicians have utilized various antibiotics empirically as part of their 'general' management of IBD. Only metronidazole has been adequately studied in controlled CD trials, but other antibiotic studies are pending. Further exploration of antimicrobial treatment for IBD is clearly warranted. Many other investigational agents in disparate pharmaceutical categories have been employed in IBD therapy; and some of these also show varying degrees of promise, including the aloe vera derivative acemannan, several formulations of heparin, and both transdermal and intra-rectal nicotine. Despite the growing list of medications and formulations promoted for the treatment of IBD, no single drug or recognized combination has yet been confirmed as dependably clinically effective. Many additional investigations of IBD medical therapy are needed, including permutations of conventional medications, along with newer agents that may be more precisely targeted to specific aspects of IBD pathophysiology. All physicians who care for UC and CD patients enthusiastically await more optimal regimens for these challenging disorders.