Adverse Events Related to Azathioprine Use in Patients With Inflammatory Bowel Disease: A Real-World Cohort Study

Azathioprine is one of the commonly used maintenance therapies in patients with inflammatory bowel disease (IBD), specifically in low- and middle-income countries. However, the use of thiopurines is questioned due to safety concerns. We aimed to assess the adverse event (AE) profile of azathioprine in IBD patients.

This was a single-centre retrospective study. All the consecutive patients treated with azathioprine were considered for this study. Data were collected from prospectively maintained IBD files. The primary objective was to assess the adverse events arising due to azathioprine use. The AEs were defined as per standard definitions. The relation between the AE and dose and duration of azathioprine use was assessed.

Among 48 patients [UC: 20 (41.7%) and CD: 28 (58.3%)] included, 30 (62.5%) were male. The mean age and the disease duration were 41.2 ± 15.7 years and 15 (5-40.5) months, respectively. The initiation and maximum dose of azathioprine were 0.91 ± 0.15 and 2.04 ± 0.58 mg/kg. The median thiopurine treatment duration was 6.5 (2.25-15), 11.5 (3.5-23.5) and 5.75 (2-12.5) months, respectively, in the whole cohort, UC and CD. A total of 25 (52.1%) patients developed adverse events [8 (40.0%) in UC and 17 (60.7%) in CD]. The commonest AEs were leukopenia in 15 (31.2%), GI intolerance in 5 (10.4%), arthralgia in 4 (8.3%), hepatitis in 3 (6.2%) and hair fall in 2 (4.1%) patients. No infection or acute pancreatitis episode or malignancy was reported. A total of 16 (33.3%) patients stopped azathioprine. AEs were the most common cause of azathioprine withdrawal in 12 (25.0%). No serious adverse event was reported.

Adverse events are common and lead to therapy discontinuation in one fourth of the IBD patients on azathioprine. The commonest adverse events are leukopenia, GI intolerance, arthralgia, hepatitis, and hair fall.