Which of the following statement(s) is/are true concerning drug therapy for Crohn’s disease?

c. Azathioprine, an immunosuppressant, has been shown to be effective in maintaining remission of Crohn’s disease

Systemic corticosteroids have been used to treat Crohn’s disease since the 1940s. Although the exact mechanism of action is not clear, nonspecific immunosuppression is the likely effect. Several well designed trials have demonstrated that Prednisone (or its equivalent) is effective in the treatment of acute exacerbations. Patients with quiescent disease, or patients who have received remission through medical or surgical therapy, however, do not benefit from long-term continued corticosteroids. Sulfasalazine consisting of a sulfonamide linked to an aspirin analogue (5-ASA) is more effective than placebo in the treatment of acute disease. This agent, however, is most effective in patients with predominantly colonic disease and is less effective than corticosteroids in treating patients with small bowel disease. Asymptomatic patients do not appear to benefit from prophylactic treatment. The immunosuppressive agent azathioprine, which acts to inhibit nucleic acid metabolism, has been demonstrated to be highly effective in long-term use. The use of azathioprine has a steroid-sparing effect with reduction of steroid dose or discontinuation of therapy. In chronic treatment, azathioprine is effective in decreasing disease activity, steroid requirements, and complications leading to surgery, therefore, in contrast to corticosteroids and sulfasalazine, azathioprine appears effective in maintaining remission. Side-effects, however, can be significant including bone marrow suppression and acute pancreatitis. Finally, cyclosporine, an immunosuppressant, has undergone extensive review with the conclusion that low-dose oral cyclosporine treatment confers no therapeutic benefit for patients with low or high disease activity and in no reduction in the need for other forms of therapy.