Azathioprine or methotrexate in the treatment of patients with steroid-dependent or steroid-resistant ulcerative colitis: results of an open-label study on efficacy and tolerability in inducing and maintaining remission

Background: The role of azathioprine and methotrexate in inducing and maintaining remission in patients with ulcerative colitis is still controversial. Aim: To evaluate the efficacy and tolerability of these two drugs in a series of patients with steroid-dependent or steroid-resistant active ulcerative colitis. Methods: Forty-two patients were treated with a daily dose of azathioprine (2 mg/kg) and, if intolerant or not responding, with methotrexate (12.5 mg/week intramuscularly), and their efficacy was established by clinical, endoscopic and histological examinations at 6 months. Patients achieving clinical remission continued with treatment and were followed up. Results: Of the 42 patients on azathioprine, 10 experienced early side-effects requiring withdrawal from treatment, 22 (69%) achieved complete remission, six (19%) achieved improvement and four (12%) obtained no substantial benefit. Methotrexate, administered to eight patients intolerant to and two patients resistant to azathioprine, induced complete remission in six patients (60%) and improvement in four (40%). During follow-up, a larger number of patients on azathioprine relapsed in comparison with patients on methotrexate [16/28 (57%) vs. 2/10 (20%), respectively; P < 0.05]. Only minor side-effects wereobserved on both treatments. Conclusions: Azathioprine is effective in patients with steroid-dependent or steroid-resistant ulcerative colitis. Methotrexate seems to be a good alternative in patients intolerant to or not responding to azathioprine.