Thiopurines & Ulcerative Colitis (UC)

Moreover, current guidelines also recommend thiopurines as corticosteroid-free maintenance therapy
Bressler et al. 2015 Gastroenterology 148:1035-58

Thiopurines are indicated for patients with steroid-refractory or steroid-dependent UC
Harbord et al. 2017 J Crohns Colitis 11: 769-84
Ko et al. 2019 Gastroenterology 156: 748-64

Thiopurines (such as azathioprine and 6-mercaptopurine) are widely used as immunosuppressive maintenance therapy for ulcerative colitis (UC), but neither the US FDA nor the EMA has officially granted a specific "approval" for their use in UC, despite their inclusion in treatment guidelines and frequent use in clinical practice.
Pugliese et al. 2018 Gastroenterology Research and Practice 2018: 4195968
Tominaga et al. 2021 Front Pharmacol 11: 582291