Low dose methotrexate in inflammatory bowel disease: current status and future directions.

Despite many recent advances, some notable limitations exist in the medical management of patients with inflammatory bowel disease. Glucocorticoids suppress active inflammation very effectively, but their long term use is associated with high rates of relapse and unacceptable toxicity. 6-Mercaptopurine and its prodrug azathioprine are effective in inducing and maintaining remission; however, a significant number of patients are resistant or intolerant to thiopurines. Low dose methotrexate, an anti-inflammatory drug, is a well established medication for rheumatoid arthritis and psoriasis. After an initial report in 1989, several clinical trials and analyses of clinical notes have examined the role of methotrexate in patients with ulcerative colitis and Crohn's disease. This review was conducted to summarize the current knowledge about the underlying basic anti-inflammatory mechanisms of methotrexate as well as the pharmacology and toxicology of this drug with particular emphasis on inflammatory bowel disease. It also critically evaluates all existing trials not only in the induction of remission but also in maintenance therapy. We conclude that low dose methotrexate is an effective and safe treatment in glucocorticoid-dependent and thiopurine intolerant patients with Crohn's disease but not ulcerative colitis. It remains to be seen whether low dose methotrexate may also be useful in long term maintenance therapy in patients with inflammatory bowel disease.