Efficacy and safety of thiopurinic immunomodulators (azathioprine and mercaptopurine) in steroid-dependent ulcerative colitis.

Background: The efficacy of azathioprine in the management of steroid-dependent ulcerative colitis is taken for granted. However, study populations frequently include together steroid-dependent and refractory patients.
Aim: To assess the efficacy and safety of thiopurinic immunomodulators in strictly defined steroid-dependent ulcerative colitis.
Methods: Survey of 34 patients with steroid-dependent ulcerative colitis, treated with azathioprine according to protocol. Therapeutical success: glucocorticoid withdrawal within 12 months, without steroid requirements during another year.
Results: Mean age was 39.1 +/- 17 years. Pancolitis and extensive colitis accounted for 50% of cases. Therapeutic success of immunomodulator treatment reached 70.6%, intention to treat analysis (confidence interval 95%: 52-84%) and 72.7%, as per protocol (confidence interval 95%: 54-86%). Mean time to steroid withdrawal was 4.6 months. In therapy successes, mean corpuscular volume and total serum bilirubin increased with treatment time (P = 0.0001). Fifteen adverse effects were observed in 13 patients (38%). Azathioprine was withdrawn in seven cases (20.6%); in four of them (with liver toxicity), treatment with mercaptopurine was indicated.
Conclusions: Therapy with thiopurinic immunomodulators (azathioprine) represents the first option in the management of steroid-dependent ulcerative colitis. Its efficacy (70%) and its acceptable safety support this view. Increasing mean corpuscular volume and serum bilirubin values may be a surrogate marker of a beneficial effect.