Azathioprine weekly pulse versus methotrexate for the treatment of chronic plaque psoriasis: A randomized controlled trial.

Background: Methotrexate is the most commonly used drug in the treatment of psoriasis with good efficacy and safety. Recently, weekly azathioprine pulse has been shown to be effective in this disease.

Aim: The aim of this study is to compare the effectiveness and safety of weekly pulse doses of azathioprine and methotrexate for the treatment of chronic plaque psoriasis.

Methods: In this randomized controlled trial, 80 patients with chronic plaque psoriasis were recruited. After detailed clinical and laboratory evaluation, patients were randomized to 2 groups to receive either weekly 300 mg azathioprine (n = 40) or 15 mg methotrexate every week (n = 40) for 20 weeks, following which the response to treatment and adverse effects were assessed. The patients were then followed up every 4 weeks for 3 months to determine any relapse.

Results: Overall, 48 (60%) patients achieved PASI 75, while 36 (45%) and 59 (73.8%) patients achieved PASI 100 and 50, respectively. On intention to treat analysis, PASI ≥ 75 was achieved in 47.5% (19/40) patients in group 1 compared to 85% (34/40) patients in group 2 (p < 0.001). However, on per protocol analysis, PASI ≥ 75 was achieved in 86% (19/22) patients in group 1 and 92% (34/37) patients in group 2 (p = 0.497). Minor clinical and biochemical adverse effects were noted in both the groups, which were comparable. One (7.7%) patient in group 1 and 4 (17.4%) in group 2 relapsed during follow-up.

Limitations: Limitations of study include small sample size and short follow-up.

Conclusion: Weekly azathioprine pulse appears to be beneficial in the management of chronic plaque psoriasis. However, it is less effective than weekly methotrexate. It can thus be of use as a therapeutic option in patients with contraindication to methotrexate or other similar agents in this disease.